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750 mighty demon

 
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PostPosted: Thu Jan 17, 2013 10:30 am    Post subject: 750 mighty demon  Reply with quote

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 #1       04-07-2006, 08:01 PM  
Gary Geiger  
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750 mighty demon

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Hi Tuner;
I have another question took home my lab scope last night to look at plug wires ( not the best way but just to compare cylinders) . What did you see in the o2 pattern that made you suspect IGN. issues was it the spikes or the hash just so I know in the future. By the way thanks for the help I think you hit the nail on the head.
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 #2       04-07-2006, 08:14 PM  
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The little skinny spikes that look like the Empire State Building. Fuel related lean spikes usually flare at the bottom like the Eiffel Tower. Generally, (with a carburetor) the mixture can't change fast enough not to leave a trail of crumbs showing it's deviation on one or both sides of the spike.

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Last edited by Tuner; 04-07-2006 at 08:32 PM.
 

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 #3       04-12-2006, 06:15 PM  
Gary Geiger  
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750 mighty demon

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Hi tuner

Spent a couple hours building new plug wires this past weekend all cyl. show good fire. Took car out for a spin with same carb tune as last post nothing changed still lean miss. Looked in the corner at the trash can then at the carb then back at the trash can (just kiding). Sometimes it's best to take a break and think what is the motor telling me . Next step went up with IFR (from .031 to .034) that took care of most the lean miss at tip in did some more pump arm adjutment feels better by the seat-o-meter. still a bit rich at idle. Other changes went back to stock IAB .070 & HSAB .040. I will try going up with IAB to see if that helps have not had much luck messing with the bleeds with past tune on carb. Do you have a suggestion on this rich problem . any way here is the log from last knight.
Attached Files session 13.6.log (123.9 KB, 514 views)

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 #4       04-12-2006, 08:42 PM  
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Try the HSAB in the .025 to .028 area. Did the scope show a bad wire? That last post has fewer noise looking blips in it, but still a few. It is suspect when there is a spike on more than one channel and the throttle position wasn't changed. Can you rig a MAP sensor?
 

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 #5       04-12-2006, 10:30 PM  
Gary Geiger  
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750 mighty demon

--------------------------------------------------------------------------------

Actualy the scope showed 2 bad but one was laying against the header and arcing to it must have been sleeping after running the valves the last time. I have the 5v reg. wired to the battery & grd. to the block the signal wire goes across the fire wall right above the dist. in the original plastic conduet the 70 chevy's came with. The tps doesnt seem to show real lite throttle pressure not sure how to fix that yet did sweep it with the dvom last night after fixing the 5v.reg wire broke got a o-3.30 volt reading on dvom. I have a 1 bar map and the 5v.reg wired up sitting on the bench but have been chasing my tail on this lean miss at tip in and havent put it on the car yet. Are you talking pri & sec. hsab or just one or the other. If I go from a.040 hsab to a .025-.028 won't that make it richer? or am I missing something in the log. Will try that after work to night if weather holds out if not maybe I can get the map. on the car
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 #6       04-12-2006, 10:48 PM  
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Change them both to keep the carb balanced at WOT. The smaller bleed in the main should make it leaner at the tip-in and richer at WOT. I think you are having the problem nearly all of these possessed carbs have. They have a rich overlap of the idle and the main at just off idle. When it misses, rich or lean, the WB sees the unburned air and files a lean report. Screw in bleeds, right? What's to loose? You have to make big enough changes to get in the ball park before you can place hit.
 

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 #7       04-13-2006, 03:32 AM  
81 Trans Am  
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Looks like a squirter problem to me. Does it still have the pink cam and 31 squirter it came with. I have a Speed Demon on a 383 SBC and I had to increase it to the white cam and a 35 squirter. I use a 37 squirter on the rear. I also use a BG one to one linkage on the secondaries. It opens them up at 18% throttle, unlike the standard one that opens them at 48%.
 

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 #8       04-13-2006, 04:31 PM  
Gary Geiger  
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750 mighty demon

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HI
weather held out last night got map sensor on the car but can not get the config. worked out need some help with that . I'm sure it's wired right ( per wiring diag.) have read logworks till my head hurt then just desided to move on. as the saying goes (you just can't fix stupid).Installed .028 hsab seemed to flat line afr under wot still a little rich at idle not as responsive as say 13.8.1 was. To answer 81 trans am question it has black pump cam and .031 squirter on the pri and pink with .031 on sec. have'nt worked alot on pump shot yet do to lean ifr. Another question for you is holley;s 1-1 link the same as BG? I think I might have one in the garage somewhere. Again I can't say this enough thanks for time and patience to every one . Here is last nights log see what you think.
Attached Files session 13.7.log (154.3 KB, 357 views)

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 #9       04-13-2006, 04:37 PM  
Gary Geiger  
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750 mighty demon

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HI
weather held out last night got map sensor on the car but can not get the config. worked out need some help with that . I'm sure it's wired right ( per wiring diag.) have read logworks till my head hurt then just desided to move on. as the saying goes (you just can't fix stupid).Installed .028 hsab seemed to flat line afr under wot still a little rich at idle not as responsive as say 13.8.1 was. To answer 81 trans am question it has black pump cam and .031 squirter on the pri and pink with .031 on sec. have'nt worked alot on pump shot yet do to lean ifr. Another question for you is holley;s 1-1 link the same as BG? I think I might have one in the garage somewhere. Again I can't say this enough thanks for time and patience to every one . Here is last nights log see what you think.
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 #10       04-14-2006, 04:44 AM  
81 Trans Am  
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Have to take a look at a black cam, have one at the shop.Your TPS doesn't look right. Doesn't do much at low throttle. Have not seen a Holley link, but the BG is slightly longer than the stock one and it mounts in the hole just below the stock one. Here is a log with TPS, MAP, Fuel Press, RPM and AFR. Haven't had much time for tuning, just got the tranny back in. I'm rich everywhere, need to lean it out a bit. I also get spikes in the AFR like yours if my sensor wires are too close too my spark plug wires. Is the car a standard. I looked at at car last year that acted the same and it was a standard. Didn't have time to do anything with it.
Attached Files Mar 11-06 3rd.log (69.0 KB, 344 views)


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Last edited by 81 Trans Am; 04-14-2006 at 04:58 AM.
 

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 #11       04-14-2006, 06:57 AM  
Andereck  
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Gary it is an ignition miss and doesn't appear to be related to load. You might check and replace your plugs, you may have cracked the porcelin on one of them. I'd bet its the same hole every time. Then again it could be a weird intake manifold distribution thing but I'd bet its a plug. The 1:1 link is pretty undriveable on the street. I tried it myself too and yes the links are all the same. The moroso piece fits a holley and a bg. You may have to drill out the hole to fit the peice in there if you're set on trying it. Sometimes you just gotta try for yourself ya know?

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 #12       04-14-2006, 04:44 PM  
Gary Geiger  
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750 mighty demon

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HI
On the subject of the spike's where do you have your 5volt reg at ? I have been wondering about that. both of my reg. are out in the engine compartment basicaly taped up & tie stapped together pretty close to the dist. Another question I have I noticed last night that the fuej pressure gauge was dropping to 3 psi at wot should not be below 5 psi should I see that in the o2 leaning out or not. Trying to figure out if I should piont the finger at the pump or the fuel reg or gauge. Car pulled hard all the way up its power curve and I did'nt see any thing in the data. I should add this is a mech. pump and areomotive reg. forgot to get the log off of my laptop this morning to post. Your question if it is a standard or not is this in referance to the trans ? Running turbo 350 3000 stall. Next question how are you loging your fuel pressure with a carb or is this a computer contoled motor ? WiLL have to take home our IGN. scope and get agood look at what cylinder that might be the one acting up don't feel it at any time during test drive. That leads me to my next question is there a way a guy using the RPM converter can trigger off of #1 cyld. and figure out what cyld is causing the problem. The TPS has never been real sensitive under light pressure but after looking at your log and how your TPS is config. in the set up I'll play around and see what happens still have to figure out map setup struggeling with that one for some reason. Thanks for all the help
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 #13       04-14-2006, 10:03 PM  
81 Trans Am  
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I have a 750 Speed Demon. I use a Auto Meter sender PN.2245. A Little expensive ($100 at Summit). I just bought 2 sensor off billjones for $20 each.They look very much like the Auto Meter sensor. If you give me your e-mail address I can forward his e-mail on to you. When configuring your TPS do you us (set to current Voltage). I use a Map sensor I got off a GM car at the junk yard, but these sensors from Bill do vacuum as well as pressure. I have a Turbo 350 with a 3500 stall and I like the 1 to 1 link, but I guess it's all a matter of personnal preferrance. Like Andereck said sometimes you just gotta try for yourself.

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Last edited by 81 Trans Am; 04-14-2006 at 10:12 PM.
 

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 #14       04-15-2006, 04:09 PM  
Gary Geiger  
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750 mightydemon

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HI 81 trans am

What is the sender screwed into? I have GM 1 bar on car just can't seem to get it config. so it will read on the laptop ( my brain can't soak up the direction) . Where do I find the (set to current voltage) not seeing it in channels setup menu. e-mail is ggeiger@hhcorp.org Did you have to change the tune on the carb for the 1-1 or have you not used the progresive link ?
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 #15       04-20-2006, 06:08 PM  
Gary Geiger  
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750 MightyDemon

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HI Tuner

Well after a week of messing with the spikes in the O2 pattern from the IGN there still here. Have tried many different things but no luck and since I'm not feeling any misfire its time to move on. Here is a list rewired TPS, O2, MAP and moved away from dist new plug wires & plugs dist cap & rotor. took home IGN. scope (sun sleuth one had to dig it out and dust it off) patterns on scope look good with no sign of a misfire. On to tuning a carb as you will see we have a map working now. Here are some logs and of course more question.
#1 In session 1 this is a third gear pull you will notice a spike right as my foot is getting acquainted with the floor any thoughts to the source of the spike.
#2 In the same session cruising down interstate at mid 13 AFR can I expect any better or should I be satisfied?
#3 in session #2 O2 pattern is choppy until min. 1.25 is this an effect of the cam or is the carb. just not right yet?
#4 in session #3 between second 50 & 55 I was going up a hill notice how the O2 pattern starts to lean a bit than corrects itself right before you see the TPS & pumpshot any reason why?
#5 what do you think about the pump shot? more work?
Attached Files session 14.6.log (90.1 KB, 357 views)

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 #16       04-21-2006, 08:42 AM  
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It’s odd that it stays so close to the same AFR most of the time except for when you have recently changed the throttle position, it hangs near 13/1 a lot. That is richer than it needs to be in the 50% load area. It’s rich at WOT so no danger there but it should be in the 16/1 area at mid load if it will run acceptably. What do your plugs look like? Kind of dark, I’ll bet. Are you watching what is going on with 471_magnum’s Mopar? Do you see how his leans progressively as he applies more load until the power valve opens and then swings to the WOT mixture? Your carb looks like a catalytic converter carb that is jetted rich, it doesn’t change AFR when the load changes. How did you get it to do that?

“#4 in session #3 between second 50 & 55 I was going up a hill notice how the O2 pattern starts to lean a bit than corrects itself right before you see the TPS & pumpshot any reason why?”

Before an answer is offered for that, can you calibrate the vacuum data with a gauge and can you configure your throttle position in the set-up to read 0% at closed throttle and 100% at WOT?

It isn’t correcting itself if your numbers are right unless you have a power valve that opens at 13”hg.

It should gradually get leaner with increasing load until the power valve opens and the mixture switches from economy to power.

I don’t know what to say about the spikes. You fixed the plug wires and they are still there. Check the wires with an ohmmeter? An open plug wire can hurt the coil. Have you got an oil filled coil lying on its side? Make sure the carbon button in the cap is touching the blade on the rotor. You saw what 471_ magnum went through to finally end up with pretty good-looking plots? Re-route some wires, twist the pairs and maybe add a filter cap like he did. It’s only easy for those two guys on HP TV.
 

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 #17       04-21-2006, 06:27 PM  
Gary Geiger  
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750 MightyDemon

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Hi tuner

I will get the TPS changes made not sure what you mean on MAP are you talking test drive with a gauge and use those readings? I used a mighty vac for my voltage settings but MAP & gauge don't match. You win the bet on the plugs. I have been following with great interest the best I can on 471 magnum thread looks like he is getting pretty close to being dialed in.
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 #18       04-26-2006, 07:47 AM  
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Hi Gary,
I’m sorry I didn’t respond after your last post. No excuse, but I was in damage control mode with the Gen7 thing. The car was like a little kid, always another excuse not to go home. I got lost in the forum maze, too. In the maze in a daze for days.

What I meant by the MAP comment was just to compare it with a gauge like you did with the mighty vac. 471_magnum had similar problems with his data in the beginning but he got it sorted out pretty good. He has some tips I’ll bet.

You must have figured out by now that it is my opinion that the possessed carburetors have “air bleed issues”. I think Andereck has a plan afoot that may include an exorcism or a de-clawing, which in this case is very similar. You can get on the bus with him (if he does it) or wait and see how his turns out. 471_magnum’s metering blocks are the original crispy recipe so his tune-up was fairly straightforward. In any case, common hand tools are all that is necessary to do any of this.
 

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 #19       04-26-2006, 04:40 PM  
Gary Geiger  
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750 MightyDemon

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Hi tuner , 471_magnum

I have been working on some other problems & waiting on the filter cap to come in for the MSD. Not sure thats going to work seeing how it fits between battery Pos & neg and the 6AL box but have to try. I am on the bus for sure if he goes that direction. So here is my next question when preforming a metering block exorcism my guess is you tap the e-hole and install a set screw or airbleed ( screw in style) right? Do you leave the existing .031 hole in the bottom of the e-hole? The MAP senor is off by about 4 inch. has to be how it's config. was looking at 471_magnum's config. on his MAP going to try that next should be a couple of day's for parts to show up. By the way if you don't mind me asking how do you store all this info in your head and keep it from exploding ? Any help on this MAP that 471 can give would be appreciat'ed

Thanks again.
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 #20       04-27-2006, 02:44 AM  
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In the hydraulic analog of electricity, voltage is pressure. In this application think of the cap. as an accumulator. It is absorbing and damping voltage spikes like an accusump does pressure spikes in an oil system.

Quote:
when performing a metering block exorcism my guess is you tap the e-hole and install a set screw or airbleed ( screw in style) right? Do you leave the existing .031 hole in the bottom of the e-hole?  

Yes, exactly. 6-32 x 3/16” brass set screws. I have done it both ways and didn’t notice any difference. I’m basically lazy so I just leave the original hole. You will need starting and bottoming taps to get the hole to fit the setscrew. Use WD-40 and patience. A headband magnifier makes it easier. Before you start to drill a hole (like to size for the tap) slip a drill bit that fits into it to eye-gauge the angle of the original to get an aiming reference.

Quote:
how do you store all this info in your head and keep it from exploding ?  

Is thaaaat why my crown fits so tight? On the other hand, curiosity is fun!
 

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 #21       04-27-2006, 05:33 AM  
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All I did on my MAP was to plug the nipple with JB weld, then drill a .028" hole to act as a damping orifice. I also put a 10 uF on the output. Vacuum source is the carb base.

I grounded the sensor and the 7805 to the LMA-2, then grounded the LMA-2 to the body to try and reduce any ground offset. I also grounded the battery direct to the body in addition to grounding it to the block. This eliminated much of the noise. My block to body ground was suspect.

I also had to fiddle with the channel configuration in logworks. I believe I put in two reference points. Don't check off "limit to programmed range". That seems to stimulate a glitch in the ranging. You want to "expand to 0-5V"

Honestly, I'm not sure what one single thing I did to get it cleared up.

The first TPS I used was bad. For some reason the output voltage would fall off. Fortunately I had grabbed an extra one from the junk yard.
 

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 #22       04-28-2006, 11:37 PM  
Gary Geiger  
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750 MightyDemon

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Hi gents

Tried putting a air bleed in vacumn hose last night (.028 .030 .040) made low reading higher & high readings lower but still did"nt match gauge readings. Just happened to fall into this by mistake when I was config MAP channel mistakenly put in 26.68in. instead of 29.68in. thing is dead nuts on my vacumn gauge now don"t know if it will stay or not. Thanks 471 magnum for the help. Installed filter cap last night and made a test loop maybe a littel cleaner patterns ? Stopped and got the bottoming taps today for the so called (exorcism) of the metering blocks . Which gets us to the questions what size of orfice do i want in each e-hole when finished and what about the sipone break? any suggestions tuner.
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 #23       04-29-2006, 01:00 AM  
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Good on the data tune up! What size restriction did you finally use in the MAP? Use the smallest one that will still show the MAP change as fast as the throttle is moved. The restriction should be at the sensor end of the hose.

Quote:
Originally Posted by G2
Which gets us to the questions what size of orfice do i want in each e-hole when finished and what about the siphon break?

.026” is where to start (and probably finish). Plug the low hole, the one below the power valve channel. Put some threads in the passage at the bottom of the idle well, where it intersects with the passage from the main well below the power valve, so you have the option of moving the idle jet to that location. Make both ends of the carb symmetrical to start with. Use .026” or .028” in the MAB. The information I have shows the “siphon break” to be .028”. If that is what yours is, that’s good. The old (40 yrs. ago) Holley nomenclature for that was “kill-bleed”.
Did you get some brass set screws?
 

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 #24       04-29-2006, 04:10 PM  
Gary Geiger  
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Quote:
Originally Posted by Tuner
What size restriction did you finally use in the MAP?
I tried the restriction thing by putting some air bleeds in the hose up by the MAP but it threw the readings off on both ends. I was'nt very clear yesterday sometimes the thought goes thru the brain but does'nt make it to the e-mail so lets try this again. What I did by mistake when setting up the MAP config the baro reading for the day was 29.68 inhg somehow I entered 26.68 inhg (must be getting old eyes don't see as good sometimes) took it out for a hot lap and my readings were right on my gauge readings will see how long it lasts. Walked out and forgot laptop this morning but will make a post of the hot lap later today.



Plug the low hole, the one below the power valve channel.

Are you talking emulsion hole that would be #3 position or lowest pos. in metering block?



Put some threads in the passage at the bottom of the idle well, where it intersects with the passage from the main well below the power valve, so you have the option of moving the idle jet to that location.

I want make sure I understand this correctly . We want to make provisions to move the idle jet from the top of the idle well to the bottom of it ?




Make both ends of the carb symmetrical to start with. Use .026” or .028” in the MAB.

I have .028 MAB in the pri & sec already.


The information I have shows the “siphon break” to be .028”. If that is what yours is, that’s good.

Yes that is what it measured with drill bits

The old (40 yrs. ago) Holley nomenclature for that was “kill-bleed”.
Did you get some brass set screws?

Have to go to lowes or sears hardware today and see about those but I do have a couple bags of BG air bleeds and IFR would like to find set screws with alenhead.
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 #25       04-29-2006, 06:39 PM  
Gary Geiger  
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750 Mighty Demon

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HI tuner

Your probably saying WTH ! my apologies on the last post as you can see have'nt got the hang of the quote thing yet.
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 #26       04-29-2006, 08:48 PM  
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Look at the way the text pops up when you start with the edit function. The text ends with [/quote] , right? That ends or breaks a quote. The start or re-start of the quote function is accomplished with [quote] . To quote someone in particular enter [quote=whoever?] . For example I quoted you as “G2” by typing [quote=G2] . I had to explain it in reverse order because it makes a quote of everything between [quote] and [quote] with the / added without displaying them when [quote] comes first and that with the / added follows. You can use the edit functions at the top of your screen, click and drag to highlight with the mouse and then cut, copy or paste to your taste. You can do it in Word first and then copy and paste it in here. The text will copy and paste back and forth.
You just have to reverse engineer this alien technology. I think it was Arthur C. Clarke that said. “The difference between any sufficiently advanced technology and majik is indistinguishable.” Or something like that.
It took me a while. I’m new in town at Internet communication but I’ve been to the corner of carb & spark street a few times.

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Last edited by Tuner; 04-29-2006 at 10:02 PM.
 

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 #27       04-30-2006, 01:47 AM  
Gary Geiger  
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750 MightyDemon

--------------------------------------------------------------------------------

Hi

well struck out today on the brass set screws but found steel ones will have to be 8-32x 3/16 looks like emulsion holes are already to big for the 6-32 . The cups in the top of the metering block that seal off the main well & idle well I figure I can drill them and put a screw in them to pull out so to clean wells after drilling whats the hot setup for sealing them back up in the metering block when done? Ok enough questions you are probably getting tired of them ! Here are the logs from last night as you will see Dr.arc&spark and his son spike are still present (maybe not as bad).
Attached Files session 15.2.log (58.9 KB, 210 views)

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 #28       04-30-2006, 04:21 AM  
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Easy there! You don’t have to drill into the well except to enlarge the power valve restriction. You don’t have to do anything that will prevent the carb from being re-possessed if it ever needs to be, with the exception of a larger PVCR. You don’t have to pull the cups out of the top of the wells and if you do you don’t have to drill any holes in them if you want to take them out. With the right tool you can get them out and re-use them without much trouble.

We need to get on the same page about what we are calling the different orifices in these carbs. The main air bleeds are in the main body along side the bowl vent pipe and are already 10-32 and have threaded brass jets in them now, right?

The “e-holes” are simple drilled holes that enter the main well from “dog-leg” shaped channel in the face of the metering block. They are the .031” (in the reference I have) holes at the bottom of a larger hole, I forget the exact size, but it is .080” to .090”? You will have to use a #36 (.106”) drill to size the hole for the 6-32 tap, but you don’t have to drill any further than the existing step where the .031” hole is now. You do not have to drill into the main well.

It is a little tricky to tap the aluminum the metering block is made of. It tries to stick to the tap, so go easy and use WD-40 or something like it for lube.

Let’s get this entire procedure straight before you start plundering. I would feel bad if a misunderstanding of something I posted here caused the outcome of this to go sideways. I’m sorry I don’t have a camera. I’m still shopping for one that will do good close-ups and doesn’t cost an arm and a leg.

Your logs look much better. The TPS is functioning in session 3 but ? in the others.
 

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 #29       04-30-2006, 12:13 PM  
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If my last post looked a little out of context that's because it was. I missed the reply that was in the green. Sorry.

Quote:
Originally Posted by Gary Geiger
I tried the restriction thing by putting some air bleeds in the hose up by the MAP but it threw the readings off on both ends. I was'nt very clear yesterday sometimes the thought goes thru the brain but does'nt make it to the e-mail so lets try this again. What I did by mistake when setting up the MAP config the baro reading for the day was 29.68 inhg somehow I entered 26.68 inhg (must be getting old eyes don't see as good sometimes) took it out for a hot lap and my readings were right on my gauge readings will see how long it lasts. Walked out and forgot laptop this morning but will make a post of the hot lap later today.

The restriction can’t change the number like a regulator but it will slow down the pressure change and hopefully will dampen the manifold pulsations. As long as the indicated manifold vacuum change follows the TPS change accurately all is good.

Plug the low hole, the one below the power valve channel.

Quote:
Are you talking emulsion hole that would be #3 position or lowest pos. in metering block?  

Yes.

Put some threads in the passage at the bottom of the idle well, where it intersects with the passage from the main well below the power valve, so you have the option of moving the idle jet to that location.

Quote:
I want make sure I understand this correctly . We want to make provisions to move the idle jet from the top of the idle well to the bottom of it ?  

Yes.

Make both ends of the carb symmetrical to start with. Use .026” or .028” in the MAB.

Quote:
I have .028 MAB in the pri & sec already.  

What did you notice when you changed that? What size was the MAB originally?

The information I have shows the “siphon break” to be .028”. If that is what yours is, that’s good.

Quote:
Yes that is what it measured with drill bits  

Good.

The old (40 yrs. ago) Holley nomenclature for that was “kill-bleed”.
Did you get some brass set screws?


Quote:
Have to go to lowes or sears hardware today and see about those but I do have a couple bags of BG air bleeds and IFR would like to find set screws with alenhead.  

I have a plot afoot re. the socket set screws.



Quote:
Originally Posted by G2
HI tuner

Your probably saying WTH ! my apologies on the last post as you can see have'nt got the hang of the quote thing yet.
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 #30       04-30-2006, 05:57 PM  
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Quote:
Originally Posted by Tuner
Easy there! You don’t have to drill into the well except to enlarge the power valve restriction. You don’t have to do anything that will prevent the carb from being re-possessed if it ever needs to be, with the exception of a larger PVCR. You don’t have to pull the cups out of the top of the wells and if you do you don’t have to drill any holes in them if you want to take them out. With the right tool you can get them out and re-use them without much trouble.

Not going to break out the drill bits till I am positive we are on the same page. Being a mechanic I'm curious about this cup tool you can never have enough tools. Can I make one or buy one?



Quote:
Originally Posted by tuner
The main air bleeds are in the main body along side the bowl vent pipe and are already 10-32 and have threaded brass jets in them now, right?

Yes


Quote:
Originally Posted by tuner
The “e-holes” are simple drilled holes that enter the main well from “dog-leg” shaped channel in the face of the metering block. They are the .031” (in the reference I have) holes at the bottom of a larger hole, I forget the exact size, but it is .080” to .090”? You will have to use a #36 (.106”) drill to size the hole for the 6-32 tap, but you don’t have to drill any further than the existing step where the .031” hole is now. You do not have to drill into the main well.

I thought my IFR blanks were 6-32 (will have to check that). When looking at the metering blocks "e-holes" that are still stock demensions the IFR blank just fall into the hole and bottom out on the .031 hole. What I'm trying to say is they are to small.

We have a decent camera at work I will get some pictures of the metering block so we are on the same page . Try to get one of the young littel wipper-snappers to show me some tricks on this computer.
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 #31       05-01-2006, 05:00 AM  
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Hi tuner

Did some measuring today on the emulsion bores that lead to the .031 orfice seems bigger is still better. The measurements were taken with a dial indicator best I can tell the bore is .127 Looked up 6-32 set screw measurement and come up with 7/64 or .109 correct drill tap size looks like it will be 8-32 unless you have a trick up your sleeve.
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 #32       05-01-2006, 09:11 AM  
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Huh? The 6-32’s fit the one (mightily possessed} I have here and it needed to be drilled for tapping. Do you know when yours was manufactured? Is it new enough to have the idle adj. under the air cleaner stud? I guess they have the right to change specifications……ect… The 6-32 set screws I have measure .1335” o.d. of the threads and the 8-32 calls for #29 (.136”) drill for 75% threads so maybe you are ready to tap already. Make sure, I’ll bet you know what will happen if the holes are too small for the tap. The ones I have done seemed to be a grade of aluminum that stuck to the taps and drill bits. I didn’t use actual aluminum tap lube, though. It worked O-K with WD-40. I have a sleeve but the trick that makes holes smaller isn’t in it until the threads are installed. 8-32’s should be fine, they would work with the one I am looking at if it had needed them. I mean there would be no problem with the gasket sealing the wells from each other.
When you get the camera action up and running we shall see.

The puller for the well cup plugs is a tapered spiral flute easy out. The one I modified to do this has on it, “No 3 use 5/32 drill”. It’s an old U.S. made, I don’t know what brand. You grind the tip off flat, a little at a time until it is the correct diameter to just start into the cup and screw itself in. The spiral flute gets an angular thread like grip in the inner wall of the cup and you can twist it and pull it out. Make it to fit the Holley cups, they are a little smaller i.d. If you grind it too short making it fit the thin walled cups it won’t fit the Holley cups. Use it in a small T-handle tap wrench. Sometimes the cups are stubborn about it and hot water or a propane torch will be part of the plan. To re-expand the plug a little to tighten the re-installation, the appropriate size ball bearing or something similar tapped into the open cup will spread the rim a bit.

--------------------------------------------------------------------------------
Last edited by Tuner; 05-01-2006 at 09:35 AM.
 

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 #33       05-02-2006, 02:09 AM  
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Hi Tuner

The cursed Demon is about year or so old and has the idle adj. in the air cleaner stud. I'm curious on the (.136") drill for 75% threads statement were did you get this for I do not want to crack this metering block and go on the list (of many I'm sure) metering block molesters. My measurements for 8/32 came from my tap & die set and please let me know if you have something differant for a 6-32 what I have is #35 7/64 drill tap size. You probably saved my but on 8/32 set screw (picked up a .136 bit today). The cup tool works great had one in my tool box that I could grind on (you know I had to try it just the kid in me.) Took out one of the idle passage cups easy to get to and easy to place back in.Enough of the rambling here is the picture of the metering block so we can get on the same page. #1 arrow is the emulsion holes that will be 8/32 I think I'm clear on that. What I'm not sure of is #2 arrow it is pointed to the hole that leads to the idle well from the main jet is this the hole that needs drilled and tapped?
Attached Images new_red_arrow_block.jpg (193.8 KB, 477 views)

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 #34       05-02-2006, 02:43 AM  
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Yes, #2 marks the spot for the idle jet auxiliary position.


Quote:
I'm curious on the (.136") drill for 75% threads statement were did you get this  

Off of the guide in the drill index. I doubt the block would crack, but the tap might break off in the hole.

6-32 is done with a .106”. Do you have a drill index with #1 through #60?

The tool is a cute trick. Old school. I laugh (cry) every time I see a magazine hero that says to “Drill a hole in it and …….”?????!!
 

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 #35       05-03-2006, 03:57 PM  
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Hi

Update holes are drilled & taped found brass set screws should be here in a few days .
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 #36       05-06-2006, 12:40 AM  
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Hi tuner

Well recieved brass set screws today and checked fit everything looks good. I still have to drill set screw orfices .026 (hope to have that done tonight). Need to get this thing back on the road has been a week with no hot laps (driving me nuts.) Anyhow here is how the metering block turned out.
Attached Images new_image_resize_new_meteringblock.jpg (21.5 KB, 431 views)

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 #37       05-06-2006, 09:11 PM  
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Good job. You got the lower idle jet location threaded too, right? I looked in some of my old notes and see that some of the possessed got 8-32’s in the e-holes. If this means short-term memory is going to include 3 or 4 years,,,,,,, what were we talking about????

I forgot your exact engine combo. Could you put the pertinent details in your next post?
 

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 #38       05-07-2006, 09:39 PM  
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Quote:
Originally Posted by Tuner
You got the lower idle jet location threaded too, right?

Yes only 6-32 in size no need to go bigger in that location.


Quote:
I forgot your exact engine combo. Could you put the pertinent details in your next post?  

355 sbc
9.5.1
-8 pro brodix
comp cam
duration @.50 int.246 exh.250 lift int.507 exh.532 108 deg.center line
airgap intake
1 5/8 headers
turbo 350 3000 stall
4.11 gears

Here is the logs from yesterday with the new set up on the metering blocks .026 on top two emulsion holes & the bottom one plugged. Being new to this I thought I would see a big change in the data with the change we made to the metering blocks. The only thing I see differant is the o2 does'nt seem to make a big of a transition when you get on the gas or off the gas but maybe I'm missing something.
Attached Files session 15.4.log (60.7 KB, 228 views)

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 #39       05-08-2006, 08:14 AM  
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Hi Gary,

What did you expect? Are you looking at the same data you are posting? I didn’t expect it to make as big a change as it did. The cruise AFR at 2200 RPM has gone from 13.5/1 to 15/1. You haven’t changed anything but the air bleeds yet, have you? You did both metering blocks, right? They should be substantially identical except for the secondary having no power valve. Part of the purpose of the changes was to reduce the AFR extremes when the throttle is transitioned from one position to another.

Have you, in one sitting, gone through all your posts to get it in mind all at once just what has changed so far? You’re keeping notes with the changes and results, right? The effort so far is to prepare for the changes that will put it where you want it. The air bleed modifications will result in the fuel coming out of the nozzle in a steadier flow rather than in spurts and globs.

What I see is a carb in early April that ran pretty close to 13/1 most of the time, maybe 13.5 at a cruise and 12.5 at WOT. The only times the mixture deviated form that area was during and shortly after transients. In post #15 you said,
Quote:
#2 In the same session cruising down interstate at mid 13 AFR can I expect any better or should I be satisfied?  

Yes, you can expect better, and no, you shouldn’t be satisfied. I asked you if the plugs were dark and you said they were. Your carb is (was) too rich at small throttle openings and light loads.

The plan here is to get your carb to cruise at an economical mixture and also deliver the mixture for best power at WOT. Right now, I think the main jet is too large and the PVCR is too small. The jet is too large for the cruise and the mixture doesn’t change (richen) enough when the power valve opens. Have you followed 471_Magnum’s experience from the beginning and read all the posts and looked at the data plots? Your experience should be similar.

If you can, get the TPS bugs worked out. You can see how important that was in 471_Magnum’s tune up. It isn’t likely you are cruising down the Interstate at 0.8% or 1.2% throttle opening.

When you record the data for the cruising and fuel economy part of this tuning drive the same route, the same way, every time if you can. A mix of neighborhood streets and a little freeway would be good, if you can do it easily. My data experience until the I***e systems became available was with racecars on tracks where every lap or pass was the same in the operation of the engine. I never realized how much easier it is to visualize what is happening in that environment than in the totally random use that street driving entails. I like the challenge. This experience should make it easier to do track tuning.
 

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 #40       05-08-2006, 04:13 PM  
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Quote:
Originally Posted by Tuner
What did you expect? Are you looking at the same data you are posting?

The change we made to the metering block was a pretty big one in my mind. If I would make that kind of change in a air bleed the carb would turn stupid. The car does start a lot quicker when warmed up & the plugs are looking much better.


Quote:
You haven’t changed anything but the air bleeds yet, have you?  

No!



Quote:
You did both metering blocks, right?  

Yes!




Quote:
Have you, in one sitting, gone through all your posts to get it in mind all at once just what has changed so far?  

Yes every night!


Quote:
You’re keeping notes with the changes and results, right?  

Yes!



Quote:
If you can, get the TPS bugs worked out.  

Will work on the tps tonight.
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 #41       05-10-2006, 04:01 PM  
Gary Geiger  
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750 Mighty Demon

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Hi tuner

Here is the new TPS config. looks much better . Also installed .031 orfice in MAP hose right under knipple for MAP. Session #1 is a little intown & country roads #2 & #3 are interstate. Please excuse the big spike in the TPS in #3 its funny what body parts pucker & twitch when you see 18 wheels and 100'000 pounds in your rear view mirror coming at you at 80 mph. Session #4 is in town may have to change that part of the test drive alot of stop and go. Here are the logs.
Attached Files session 15.8.log (132.1 KB, 261 views)

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 #42       05-12-2006, 01:03 AM  
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Hi Gary,

Way to go, the TPS is working excellent. Eye gauge the location of the edge of the butterfly to the top of the transition slot and the % of TPS for reference in this discussion. It looks like the richness at the top of the t-slot issue, if you actually have it, is at a higher % of TPS than 471_Mopar’s occurred. There is bound to be a difference in your two set-ups. What are the jet sizes and PVCR diameter in your carb? Have you tried a smaller primary main jet yet? I think is it smart to tune the low power running and gas mileage area first and leave the WOT for later. These changes can include some “crowds” of the primary to heavier load without the secondary and WOT shots too, but the main focus will be on the cruise and light acceleration? Is that the way you want to focus on it? What # power valve?
I guess if all your body parts are still attached, puckered or painted, it’s good.
 

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 #43       05-12-2006, 02:26 AM  
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750 Mighty Demon

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Hi tuner


Quote:
What are the jet sizes and PVCR diameter in your carb?  

JETS
PRI #76 SEC #85 PVCR .059 all still the way they came out of box.


Quote:
Have you tried a smaller primary main jet yet?  

No! think I should step down 1 or 2 sizes to start with?



Quote:
I think is it smart to tune the low power running and gas mileage area first and leave the WOT for later.  

sounds like a good plan to me maybe it will stabilize the needle in the fuel gauge.



Quote:
Is that the way you want to focus on it? What # power valve?  

Yes! It has a 6.5inhg in the pri & sec is pluged

The big 2.5 mile track here opened last sunday where the 500 takes place so it is rainy season again calling for rain next 5 days. Hopefuly weather man is wrong again.
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 #44       05-12-2006, 05:38 AM  
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Quote:
Originally Posted by G2
think I should step down 1 or 2 sizes to start with?

Yes, at least. For the light load stuff you want to take fuel away from it until it turns stubborn and pouts about it. You can’t hurt it if it gets too lean at a light load unless you force it to do something when it is being stubborn. At heavier loads, pulling a trailer or racing, sustaining a lean condition for long periods is not good. The little time it will spend “out of tune” while you are experimenting to get it “in tune” is harmless. It’s worse for it to run so rich it’s fouling the oil and washing oil off the cylinder walls. Didn’t your oil get black pretty quick after an oil change?

Your air-gap manifold is a single-plane or dual-plane?
 

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 #45       05-12-2006, 03:59 PM  
Gary Geiger  
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Hi tuner


Quote:
Your air-gap manifold is a single-plane or dual-plane?  

dual-plane

I want to make sure we are on the same page with the t-slot issue. You said to eye gauge the location of the edge of butterfly to the top of the t-slot & the % of tps for referance. If I understand this correctly I'm looking down the throttle bore from the top to eye gauge the t-slot so we know when the butterfly is past the t-slot on my logs right? Got the jet change made last night steped down to #74 on primary but no test run.
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 #46       05-12-2006, 04:09 PM  
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Yes, the plan is to have a general idea of the range in the TPS% of the t-slot influence. 471_Magnum's rich spot was in the 5% to 8% area. Yours seems to be higher than that. The difference in the two set ups is most likely the reason. The two carbs are quite different. The 870 has larger butterflies and shorter t-slots than the 750 daemon.

--------------------------------------------------------------------------------
Last edited by Tuner; 05-12-2006 at 10:33 PM.
 

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 #47       05-13-2006, 01:52 AM  
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Hi tuner & 471_magnum

Did someone say jealous! Heck yeah I'd like to have the extra stroke on the crank and another 100-150 HP not to mention 16 mpg. Here is two pictures the first one is in early april (can you say rich) and the second one is today's setup. Please excuse the differant sizes still trying to figure out how to shrink pictures.
Attached Images spark 1.jpg (231.2 KB, 389 views)
spark 2.jpg (19.8 KB, 374 views)

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 #48       05-15-2006, 04:34 PM  
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Hi Tuner

Got a break in the rain yesterday to get the car out temp for the day was cool 48 deg. To bring you up to date #74 jet on primary side no other changes. Car was good on highway (logs 1&2) . Log 3 is country roads and a little in town car not to bad can feel a slight surge in the 2000 to 2300 range not all the time and comes out of it pretty easy with just a littel movement in the pedal. Log 4 is in town car is not happy in the 1500 to 1900 rpm range surges bad with afr in the 15.4 to 16.5 range look at log 4 between min 3:30 & 3:55 . The butterfly to the top of t-slote is 16% the way I came up with this is to stick a 90 deg pick in the top of the t-slote and open the throttel till it made contact. The secondary opens at 56% just for referance later. You may have missed my last post take a look at the plugs in that post what a differance. What is your thought on the surge at low speed cruise? (airbleed?)
Attached Files session 15.9.log (136.0 KB, 176 views)

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 #49       05-16-2006, 03:14 AM  
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Hi Gary,


Quote:
Originally Posted by G2
What is your thought on the surge at low speed cruise? (airbleed?)

Yeah, maybe. It looks a little lean at the t-slot when the vacuum is low, like after a shift when you have left your foot steady and the vacuum drops with the RPM change. You might only need to go up a flat or two on the needle & seat adj. nut. I put some comments in your session 4 and here it is back at ya.

A part of what we are facing here is the air-gap manifolds are not famous for their excellent mixture distribution. I couldn’t think of a nice way to say what I really mean. One cylinder can be the one that is getting less fuel and you have to put enough fuel in to keep it firing and the others end up richer than they need to be and that wastes fuel.

If you could take a 2x4 x 6” long, drill ¼” holes in two rows of 4 for a plug board, you can look at them in the position they are in the engine all at once and get an idea of how close they are to running with the same mixture. A manifold with exhaust heat will get better mileage because of the distribution improvement. In the heat of the summer it might not be a big deal. It will be interesting to see how the plugs compare.


Quote:
Log 3 is country roads and a little in town car not to bad can feel a slight surge in the 2000 to 2300 range not all the time and comes out of it pretty easy with just a littel movement in the pedal. Log 4 is in town car is not happy in the 1500 to 1900 rpm range surges bad with afr in the 15.4 to 16.5 range look at log 4 between min 3:30 & 3:55  

I think when you get the low load area to be a little richer, if it is by manipulating the float level and/or the idle jet/air bleed combination, it will clear it up.

If you can safely do a session with a few moments of WOT the relationship of the jet to the PVCR could be examined.
Attached Files G Geiger 5-15-06.log (137.2 KB, 201 views)

 

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 #50       05-16-2006, 04:30 PM  
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Hi Tuner


Quote:
It looks a little lean at the t-slot when the vacuum is low, like after a shift when you have left your foot steady and the vacuum drops with the RPM change.  

Yes it was lean at the t-slote do to idle mixture screw adjustment got in a hurry trying to beat the rain. Added some more fuel with the mixture screw has taken the surge out at 1500 to 1900 rpm range. Going to step down one more size in pri. jet to see what happens.


Quote:
You might only need to go up a flat or two on the needle & seat adj. nut.  

Already 1/4 way up sight glasson primary side.
.


Quote:
A part of what we are facing here is the air-gap manifolds are not famous for their excellent mixture distribution. I couldn’t think of a nice way to say what I really mean.  

Well you can't always be the nice guy and I do appreciate the honesty.( Andereck said something about ditribution early on in this discussion thums up to him) I might add you are correct again #6 cyl is the culprite pulled all the plugs two days ago all look like the second picture in my post of the plugs except #6 .
I will try to get some pictures of all them in a lineup to post. Now to the questions what intakes do you prefer for a setup like this?


Quote:
If you can safely do a session with a few moments of WOT the relationship of the jet to the PVCR could be examined.  

The weather is supose to be better this weekend will get some WOT runs then .
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 #51       05-16-2006, 06:58 PM  
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Gary,

1/4 of the window is usually a good starting point on the float levels, but you can go much higher if need be. Most Drag race cars will be about 1/2 window, and Oval Track cars will be about 3/4 of the window.
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 #52       05-24-2006, 06:22 PM  
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Hi Tuner

The sun has decided to come out and play here at least for a couple of day's. Have been playing with IFR juggling between .031 & .034 motor likes .033 right now with the pump shot problem. After doing many more logs & adjustments on the pump cams I finally stuck my head and the laptop under the hood to see what was going on. It's amazing what happens when you open your freakin eye's and look down the carb to watch the pump shot instead of just looking at log's. What I'm seeing is at about 2% to 4% of the TPS is fuel bubbles coming out of pump nozzle at 5% I start getting fuel. The pump arm to adjustment bolt is set at .015 @ WOT and the arm moves as soon as you move the throttle linkage. Have tried white, orange, Blue & green cams. My thought is I should be seeing the shot sooner but being a first timer at this I'm not sure. Can you give some advice on this? I have read a couple of other post you talk about using a file to change the profile of the cam. What kind of file are you using? My new metal file won't even touch this stuff. In your last post you wanted to see some WOT shots. I have just been working on the cruise & pump shot issue but hopefully those will be logged soon. I would like to say thanks again for all of your help on this demon. Myself and many others in this forum are extreme'ly lucky to be recieving this info for free. The word thank you is not used enough anymore so TUNER thank you!!!!
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 #53       05-24-2006, 08:20 PM  
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having the exact same issue with my 850 mighty demon, ive tuned out all but a slight hesitation under light acceleration. been fooling around with cams and nozzles and noticed the same thing i get nothing but bubbles in the area of throttle position where the hesitation is despite the fact that i the pump arm moves as soon as the throttle does(no play). i know if i could get the pumpshot a little sooner it would clean up the hesitation.

i found one other thing that really helped with the lean spike i had when i floored it, i filed off one side of the screw that holds the nozzle in place to allow more fuel to pass and also notice on that the the little round black gaskets for the bottom of the nozzle seem too large(the ones that came with the carb) the inside diameter really hugged the screw i had some spare gaskets from another set squirters and they matched the I.D. of the squirters on the carb better. i also took a drill bit and by hand put a very slight chamfer on the the inlet of the squirter.

so between filing the screw,the gasket and the chamfer i have a lot better flow to the squirter nozzle because thats what you want determining the metering of the fuel.

i made only those changes and it was like night and day, the bog was gone.......just thought i would share that cause it worked for me.

now to fix the hesitation..................

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 #54       05-25-2006, 07:14 AM  
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Gary, it’s good you got some time between showers. Glad to hear from you. Thanks for the complement, but you guys who are doing the work are the ones who deserve the credit. Look at what you’re learning and how you’re sharing it.

I don’t know if it was the sound of distant thunder or the slaps of the hand to the forehead when I read hemitodd’s post. What a lesson in taking things for granted. In the last few years many of the gaskets for the acc.pump disch. nozzles that show up in the various carb kits have been like he described. I have been routinely using old gaskets and scrounging the old Holley thin paper ones from the bone pile. Some if those gaskets are the laminated some kind of stuff that looks like crinkly rubber on a metal washer. Those things will swell into the hole with some fuels. Good trick on the small relief on the threads to allow more flow with the larger nozzles, too.

hemitodd, start a thread, if you like, we’ll discuss your hesitation. Have you got data?

Gary, it should discharge as soon as you move the throttle. You shouldn’t have to modify any cams to get it to do that. A cam like the blue #427 one that has a sharp corner to lift the pump lever initially should squirt pretty good if the lever is at the correct angle when at the idle. Some times you have to blacksmith the lever a little to get the angle so the cam picks it up closest to the fulcrum first, at the far edge of the cam from the throttle shaft. I don’t recall saying anything about filing pump cams, I think that was in a dialog with Dr. Mike. They are tough little buggers. The only time I grind on them is when I need a 50cc pump that isn’t quite 50cc’s but more than you can get with the small cams. Some times circle or road racing, where the throttle is always picked up at high rpm’s, I’ve ground on them to get rid of all but enough pump shot to start the engine with and get out of the pits. You don’t need a lot of pump if you are already at 4500 RPM.
 

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 #55       05-25-2006, 04:51 PM  
Gary Geiger  
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750 Mighty Demon

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Hi Tuner

Last night after reading hemitodds post it got me thinking so I stoped and pick up a #40 squirter kit. What a differance that made along with #336 pump cam (I think that was the number slept sence then). I have to say thank you to hemitodd great tip! I noticed that the kit not only cam with metal washers but the bolt was drilled threw the center and the spuirter was chamfered on the end (bottom side). Going to try a couple different pump cams with this squirter to see what works best . I have a log now with WOT so we can look at PVCR to jet relation but I forgot it this morning (dummy) have freaking meetings all day so I will post it tomorrow. The changes I have made are went up with IFR from .031 to .033 also went down with IAB from .070 to .066 (original jet was 76 went down to 74) I think that is to big of a jump because its rich at idle and cruise is in the low 14afr but no drill sizes between .069 and .066 (bummer). Here is the part I know you just love (ha. ha) can you or better yet will you please explain the math in figuring out the correct jet to bleed size one of my books has it in it but I'm just not getting it. I will try going back up to .069 IAB and a piece of wire or two maybe just to see but I need the knowledge of the math for the next time. thanks again tuner! & you to hemitodd!!
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 #56       05-26-2006, 04:46 AM  
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no problem gary, just reminded me of some issues i had with my mighty demon so i thought i would share,
im going to try experiment a bit more with cams this weekend. im getting closer and closer with this carb thanx to this forum and people like tuner.

i'll keep reading along to see how you make out and if i make any headway i will let you know

tj
 

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 #57       05-26-2006, 04:10 PM  
Gary Geiger  
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Hi tuner

Here are the logs I said I would post. The second log is were I am at now. Changes are #40 squirter and #336 cam. What do you think? Session 16.4 info is in sessions
Attached Files session 16.4.log (149.6 KB, 199 views)
session 17.2.log (145.1 KB, 178 views)

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 #58       05-26-2006, 06:02 PM  
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Any time you're going up to or over a .040" squirter nozzle you should go to one of the Hollow squirter screws.
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 #59       05-26-2006, 07:46 PM  
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I think Farfegnugen! (Klaus, help me with the spelling, please.) Big Oil wants you to put it back the way you found it. What does the driver think?

What did you do that richened it up so much in the second set of sessions? What you had going in 2016 will give better mileage than the changes that made 2017 so much richer. Was that just a test to see if anybody’s paying attention?

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 #60       05-26-2006, 08:50 PM  
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Fahrvergnuegen = The Joy of Driving
 

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 #61       05-26-2006, 09:29 PM  
Gary Geiger  
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High Tuner

Just two changes up with IFR & down with IAB. Thinking about trying smaller IFR when I get pump shot blacksmithed into place. Not trying to test anyone or see if they are paying attention just trying to get out of the 15 & 16 AFR range motor does'nt like it.
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 #62       05-26-2006, 10:18 PM  
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I agree, you have to make it run smooth. The area of load where I am talking about lean mixtures for economy is when you “crowd” the throttle from the level road load of what ever will run well to lower vacuum, 12” or 10” hg down (this is the main jet area) to the power valve opening point where it should swing back rich to the WOT AFR. The higher vacuum of cruising dilutes the mix with exhaust gas and it needs to be rich enough to fire regularly. How lean an engine will run at level road load depends on the valve timing, the amount of overlap. If you can get it to go to 16/1 or so at 10” to 8” hg. it will save fuel. The PVCR richens it back up for WOT. Visualize it like this, 12.5 to 13.5 (what ever runs smooth) for idle and very light load and high vacuum, gradually leaning to 16/1 (or leaner if the valve timing allows it) at about 60% or 70% load and higher RPMs (over 2500?), 12.5/1 for heavy load and max power. The lean mixture will want more timing (vacuum advance).

You asked a while back what manifold I like for mileage. I don’t know what to say, the aftermarket units are not engineered with the rigor the stock manifolds were. The gains in air flow at WOT are the focus, I think. The regular performers with exhaust heat and the others like them are probably better than an unheated manifold. I have noticed the distribution thing with the air-gaps I have dealt with. Seems it was #6, too. I don’t remember specifically, but it was on that side of the engine. (ZZ4 crate eng. with a 750 Holley and headers.) The performer RPM is lean in 8 and rich in 5 at WOT. They are on the same venturi so fixing that is a trick.

Tech@BG can answer that question with the 8 LC-1’s?
 

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 #63       05-26-2006, 11:20 PM  
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Hi tuner

[quote]You asked a while back what manifold I like for mileage.

What I was trying to ask was what single plain intake has good distribution? The gas mileage is important and I want it as good as I can get it but this is not a daily driver. I have to wonder how good a 70 nova with 4:10 gears 3000 stall and no overdrive can get. I am thinking about buying a new one for the next motor I'm starting to piece together
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 #64       05-26-2006, 11:24 PM  
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Quote:
Originally Posted by Tuner
I agree, you have to make it run smooth. The area of load where I am talking about lean mixtures for economy is when you “crowd” the throttle from the level road load of what ever will run well to lower vacuum, 12” or 10” hg down (this is the main jet area) to the power valve opening point where it should swing back rich to the WOT AFR. The higher vacuum of cruising dilutes the mix with exhaust gas and it needs to be rich enough to fire regularly. How lean an engine will run at level road load depends on the valve timing, the amount of overlap. If you can get it to go to 16/1 or so at 10” to 8” hg. it will save fuel. The PVCR richens it back up for WOT. Visualize it like this, 12.5 to 13.5 (what ever runs smooth) for idle and very light load and high vacuum, gradually leaning to 16/1 (or leaner if the valve timing allows it) at about 60% or 70% load and higher RPMs (over 2500?), 12.5/1 for heavy load and max power. The lean mixture will want more timing (vacuum advance).

You asked a while back what manifold I like for mileage. I don’t know what to say, the aftermarket units are not engineered with the rigor the stock manifolds were. The gains in air flow at WOT are the focus, I think. The regular performers with exhaust heat and the others like them are probably better than an unheated manifold. I have noticed the distribution thing with the air-gaps I have dealt with. Seems it was #6, too. I don’t remember specifically, but it was on that side of the engine. (ZZ4 crate eng. with a 750 Holley and headers.) The performer RPM is lean in 8 and rich in 5 at WOT. They are on the same venturi so fixing that is a trick.

Tech@BG can answer that question with the 8 LC-1’s?

As far as the "Best" intake for fuel mileage an active intake moving the runners would probably be the hot ticket.

Tunner, not sure what question your exactly asking.
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 #65       05-26-2006, 11:46 PM  
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Quote:
Originally Posted by Tech @ BG
As far as the "Best" intake for fuel mileage an active intake moving the runners would probably be the hot ticket.



Like a slinky with a flexible covering moving up and down?
 

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 #66       05-26-2006, 11:57 PM  
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Quote:
Originally Posted by Andereck
Like a slinky with a flexible covering moving up and down?


That's probably the simplest way to picture one.
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 #67       05-27-2006, 09:21 PM  
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Quote:
Originally Posted by G2
Here is the part I know you just love (ha. ha) can you or better yet will you please explain the math in figuring out the correct jet to bleed size one of my books has it in it but I'm just not getting it.

The only mathematical relationship between jets and air bleeds I recall is in Weber (and similar) carbs for the main to the air corrector and then only as a suggestion for starting up an unknown combination. Because those are usually an IR application (one venturi per cylinder, no plenum) and the L/D ratios of their flow paths are different, nothing about that jet/air bleed math applies to what we are discussing. What book is it you are referring to?

As far as I know, the only way to do it is experimentally. The idle/low speed circuit just has to be solved like a puzzle, but for the MAB in the Holley types there is a “line in the sand” (for me anyway) that makes things crazy. There is an empirical sort of “hunch” that a certain combination is in the ballpark for similar engines, but every once in a while my hunch is wrong. The lessons learned on changes made to the same engine, manifolds, headers, port volume, etc. and how they can jerk a fine running carb into drooling and slobbering and being sneezy are pleasant memories that make me wonder if the next one will even start. The scary part is so many things are counter-intuitive. Engines and carbs are just like the people who made them and use them, they exhibit group behavior but they still need to be treated as individuals.
 

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 #68       05-27-2006, 11:15 PM  
Gary Geiger  
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Hi Tuner

I probably have it wrong on the math question. Let me find the holley book I was reading a while back and see exactly what it say's. I did'nt mean to put you on the spot with the intake question but I think the BG tech answered it in another post. Just finished installing a new fuel pump just a minute ago seems fuel pressure is dropping to 3psi at 4000rpm will see what that does. Changed the carb back last night for the fuel gods with any luck will have some wot logs tomorrow.
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 #69       05-28-2006, 12:42 AM  
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I don’t feel like you put me on the spot about the intake question. If fuel economy is even a slight consideration, exhaust heat is a must, whatever type of manifold. What did you conclude from BG tech’s answer?

There is math that solves for air flow and fuel flow in many sources such as the C. F. Taylor MIT Press publication. It can be used to postulate a jet size for an airflow and venturi diameter. Basically, the Bernoulli theorem with corrections for viscosity and compressibility. I’ve written a spreadsheet that uses it (the math). It was a good mental exercise but isn’t of much practical use. You still have to change jets until the engine is happy, then change the weather or the headers or (?) and do it again……or someone else will kiss the trophy girl.

Because everything in physics has some degree of inefficiency, there is a need for coefficients in the math to correct for losses like compressibility, friction and viscosity. In fluid physics, the coefficients vary in a non-linear manner with the pressure drop, particularly within the range of pressures that carburetors function, 0” to 5” h2o, and usually below 40” or 50”. The orifice (jet) coefficients are extremely sensitive to entry design, square edged, angle of chamfer and length/diameter ratio. Because of the non-linearity of the coefficients, the math falls apart at small flows and orifices such as those in idle systems. The (lack of) quality control in things like transition slots makes it even more difficult.
 

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 #70       05-29-2006, 07:16 AM  
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Quote:
What did you conclude from BG tech’s answer?  

Basically it depends on your set up is what I got out of it. The reason I ask the intake question was it sounds like youself and a few other people in this forum get to spend some time on dyno's. I'm starting to gather up parts for a 383 . Got any good combinations on 383? The math question was suposed to be about the relationship between PVCR and jet but I think we will cover that at some point.Here are the WOT pulls from today there seems to be a lot of noise in the upper RPM range.I left some notes in session #1. The other two sessions are just around town meesing with pumpshot .
Attached Files session 17.6.log (115.3 KB, 199 views)

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 #71       05-29-2006, 11:12 AM  
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Hi Gary,

The noise coming back is a bummer, you had it cleaned up pretty good. Something so obvious it’s invisible is probably the cause. You don’t have another crazy plug wire? Is the rotor blade touching the carbon button in the cap? How much plug gap are you using? Have you tried the filter caps. that 471 Magnum used? I wonder if there should be a filter cap on the 12v supply for these devices?

I don’t have any particular favorite intakes or combinations for a 383, sorry. For street use a Q-Jet is my personal choice but I usually just tune whatever shows up and make the best I can of it. I have noticed that dual-plane manifolds that have the divider down to open up cross talk between the halves usually have distribution issues. The L-88 Chev needed a 4 jet split on one end of the carb and 2 jets on the other. The Performer RPM has a klanger with 5 rich & 8 lean when used with a 600 Holley with a ½” thick open gasket under it. It isn’t so bad with a 4-hole gasket and it may not be that way with other carburetors.

On the jet-PVCR relationship deal, some authors have suggested paying attention to the Area Ratio changes in the context of if you change one, change the other to compensate in order to keep the WOT the same. In the pre-I***e days that made some sense but it is a leap of faith to assume the WOT is right in the first place, as we have all seen in the logs posted in the forum here. Keeping track of A/R changes in your notes makes things make more sense. Carbs with metering rods you have to treat that way if you change jets and want to keep one or the other (econ. or power) mixture the same.

On your logs: It looks like you have the richer jetting in there? The noise in the WOT is ?? but the bottom of the spikes is a fairly flat line for what that’s worth? Sometimes, the pump looks like it is too big a shot initially and then doesn’t have enough duration. A smaller pump shooter will discharge less for longer so? If the throttle response is good, that’s what matters. This paragraph has a lot of ???? in it??!!

By the way, I meant to tell you, the trick with the 90deg. pick to find the throttle position at the top of the t-slot, I like that. I’ll give you credit when I use it.

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 #72       05-29-2006, 05:20 PM  
Gary Geiger  
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hi tuner


Quote:
You don’t have another crazy plug wire?  

Nothing touching headers and I don't feel a miss.


Quote:
Is the rotor blade touching the carbon button in the cap?  

I will check that again it was last time the dist.cap was off.


Quote:
How much plug gap are you using?  

.032


Quote:
Have you tried the filter caps.  

I installed one from MSD between the battery & MSD box. Is there any others that need to be installed?


Quote:
The L-88 Chev needed a 4 jet split on one end of the carb and 2 jets on the other.  

So your saying you were running 4 differant jets? Being new to this tuning thing is this how you take care of some distrabution problems?




Quote:
On your logs: It looks like you have the richer jetting in there?  

74 in the front. We have not discussed the secondary at all so it still has 84 in it.


Quote:
Sometimes, the pump looks like it is too big a shot initially and then doesn’t have enough duration. A smaller pump shooter will discharge less for longer so?  

Still playing with the primary pump shot that is a #336 cam in it now with the #40 squirter screw & a .031 squirter. I hope the secondary pump shot is a littel easier (who am I trying to kid).



Quote:
This paragraph has a lot of ???? in it??!!  

Turn about is fair play in this part of the country!


Quote:
By the way, I meant to tell you, the trick with the 90deg. pick to find the throttle position at the top of the t-slot, I like that. I’ll give you credit when I use it.  

Thank you


Quote:
How was the Indy 500, did you go?  

No did'nt go I grew up in speedway and as I get older I can't stand the crowds so I watch the race on delay from my recliner in the airconditioning ha ha !
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 #73       06-10-2006, 12:57 PM  
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Hi G2


Quote:
So your saying you were running 4 differant jets? Being new to this tuning thing is this how you take care of some distrabution problems?  

The 850 vac.sec. carb on L-88 Chevys used a 78 and an 82 jet in the front and a 82 and an 80 in the rear. This was used with a manifold that had the center divider cut down to within about 3/8" of the floor of the upper runners. Kind of like the Air Gap manifolds are now. At WOT the mixture was even enough to hold at WOT pretty much indefinitely. Part throttle at around 3000 was a funky deal.
 

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 #74       06-10-2006, 06:34 PM  
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I mentioned this in another thread so sorry if its redundant.

I had similar noise spikes and installed a line filter on the LM-1 power input and fixed the problem. I made my own pi filter with 2 caps and a choke (coil). power comes in, across the top of the first cap (bottom of cap tied to ground), through the choke, then across the second cap and out. All parts were shelf stuff at Radio Shack.

I've beat on it pretty good since installing the filter and no noise at all.
 

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 #75       06-12-2006, 09:41 PM  
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Hi eric68

[quote] I had similar noise spikes and installed a line filter on the LM-1 power input and fixed the problem. I made my own pi filter with 2 caps and a choke (coil). power comes in, across the top of the first cap (bottom of cap tied to ground), through the choke, then across the second cap and out. All parts were shelf stuff at Radio Shack.[quote/]


I have a couple of question and bear with me on this because I'm not a electrical wizard.
#1 How are you wired for power? ( are you using what was supplied with the LM-1)

#2 Is this correct I'm looking for a line filter two caps & a choke at radio shack?

Thanks for the info
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 #76       06-12-2006, 09:48 PM  
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I use the standard cord that come from I***e witrh the cig lighter plug on the end. I bought a femal cig lighter and wired it to my fuse block so I can use the I***e cord without any mods (I may want to use it in other peoples cars eventually).

Here is what you want from R.S.

A generic circuit board (blank you can solder to)
Two capacitors
One choke. (its a coil of wire wrapped around an iron core)
I also added a diode on the input

Hope that helps

Eric
 

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 #77       06-21-2006, 08:23 PM  
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Hi Tuner

All the discussion on spark plugs thought I would post some pics. The first one is in february the carb right out of the box. The second one is from a month ago. I would like to say keep the info and links to differant sites coming to those of you posting them the info is great. Any comments on the pics I posted would be appreciated.
Attached Images Img2006-06-21 08352273_22.jpg (43.1 KB, 324 views)
Img2006-06-21 08352657_26.jpg (59.5 KB, 328 views)

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 #78       06-21-2006, 09:04 PM  
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Of course I am not Tuner and know nothing about reading plugs because I have a Demon carb  but I have to say there is a major improvement between the before and after.

I will say though on the after pic cylinders 3, 5, 7 and 2 look richer than the rest.
 

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 #79       06-21-2006, 09:48 PM  
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Good pics Gary. You guys that are reading the side electrodes tell us what you see there?

Erick, in the written word here you can't see the gleam in my eye and get the body language so I should be more careful. In the remark I made in the other spark plug reading thread you are referring to I meant that if a guy only possessed a carb that made plugs look like Gary's first pic and had little experience with engines that were tuned correctly he could conclude that soot on the shell was a sign of something about WOT. It was a joke but I told it to myself, I guess. I did not mean to imply people who have those carbs are less fortunate as individuals except to have to put up with a carb that fouls plugs, dilutes the oil with gas, gets horrible mileage and in DartGT's case (for one example) burns the electrodes off of plugs. On the other hand, it is understood that tuning is necessary because every circumstance is different.
 

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 #80       06-22-2006, 03:43 AM  
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Oh don't worry Tuner . . . I got the joke  I'm just giving you a little back . . .

On your other question I have to say a couple things .. .

1) its very hard to read a plug accurately from a pic on the net -- especially one that isn't a real close up. You cannot rotate the plug picture (well I suppose you can rotate the monitor but it doesn't help see the other side of the plug) and you can't hold the plug up in the bright sunlight.

2) Its also very hard to read a plug (at least for me) that has seen lots of usage. What you are reading after a few miles is mostly a combination of idle and cruise -- not really any significant WOT time. I like to install a fresh plug (yes just one) then make a WOT blast and shut down the motor. Then read the plug to see what AF mix looks like.

3) With the first two things in mind I think that the 1st plugs show rich (real rich) at cruise and idle. Cannot tell muich about WOT.

4) the second plugs show much closer to ideal over all, but still, we're looking at an "average" of whatever kind of driving was done.

5) To answer your question, the mark on the strap (if I see what I think I see) shows an aneal mark past the bend closer to the base indicating a plug that is on the hot side or too much timing, or both. (and I am looking at cylinder # 4)

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 #81       06-23-2006, 07:53 PM  
Gary Geiger  
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Here are a couple more spark plug pics. This plug has 1 pass on it.
Attached Images spark plug14.JPG (11.2 KB, 406 views)
spark plug-297.JPG (14.6 KB, 308 views)
spark plug-38.JPG (13.5 KB, 339 views)

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 #82       06-23-2006, 11:27 PM  
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Hi Gary,

Again, nice pics. Too much work, though. I like an illuminated magnifier. I guess I’m just lazy.

The plug is too hot. Brodix, on their web site, recommends an NGK 8 heat range and that sounds like a good choice to me. For the street, maybe a 6 or a 7, but the plugs in your pics are all too hot.

Good show of the little ring at the base of the ceramic. It’s a little further down than I prefer, but it’s probably because the plug is too hot. If your data confirms a good WOT A/F that’s the case.
 

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 #83       06-24-2006, 12:04 AM  
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I will try the nkg plugs but how do I tell this plug is to hot (for future referance). Data is showing 12.0 AFR I need to bring that up a touch. I see that you have a camera now. Nice pic's on the 340 Tri-power
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 #84       06-24-2006, 12:43 AM  
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In your first pics in post # 77 I could read the number on the plug. That and the look of the deposits all white and chalky, go together to suggest too much heat. It is hard to see because the picture of the cleaner plugs isn’t close up enough but the center electrodes look as if they have lost some of the sharp off of their edges. To compare the edges to a brand new plug of the same number is an important clue. I didn’t think you were too lean because of having seen your data and knowing your tuning was getting dialed in. As rich as you are, a plug that looks like those and the one in post # 81 is too hot. With that rich an AFR the ring should be further toward the tip if the heat range is closer to what it should be for the use. The old spark plug catalogs used to say on the bottom of every page, “Use one step colder for trailer towing.” Those are some nice looking plugs from your original (out of the box) carb calibration. “Big Oil” likes those.

If you can get the light right, you can take close-up pictures through a magnifying glass of your plugs and see all the way down in the shell. I haven’t tried it with a still camera yet, but I’ve done it with a video camera. The camera I’m using is nice but it’s borrowed, darn. I didn’t take the pic of the `Cuda carbs or it would show the wire connecting the throttle to the TPS. (digdig-hehe)
 

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 #85       06-24-2006, 01:18 AM  
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Hi tuner

The last set of pictures were taken with a digital camera through a microscope at work. So what you are saying with 12.1 AFR at WOT and the correct heat range the ring will work it's way up the porcelain. The first set of pic's are champion plugs & the second are AC R43LTSM. Just picked up a NGK plug book last week will have to try some.
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 #86       06-24-2006, 01:37 AM  
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Hi Gary,

Yes, the ring will move closer to the tip but also the tip is moving closer to the ring. The ring will move up from the radius at the bottom to a location on the side of the ceramic above the radius.
 

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 #87       01-29-2007, 06:28 AM  
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How About an update?

--------------------------------------------------------------------------------

Hi Gary,
Just read this thread, thoroughly enjoyed it! Lots of good info. Was wondering what the latest was with your tune-up, any current logs, fuel mileage, ET's? How about your LM1 system, did you ever get the spikes out of your logs? Did you install the line filter that Eric68 mentioned? I have a Bracket Car I'm tuning 1st and trying to learn the ropes, lot's to learn, but lot's of fun learning. I can't wait to start tuning my street car, it's a 69 Nova with a 427 and a 200-4R transmission with 4.10 gears.
Thanks to you and Tuner for all the info.
 

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 #88       01-29-2007, 06:52 AM  
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Hi Slowpoke
The tune up is pretty good as far as driveability. I never have checked gas mileage but I can tell it has probably doubled from where I started. The car is mostly driven to cruise ins and a little strip duty so gas milage wasnt my main concern. I have not got ride of the spikes in my logs and still need to figure out what line filters are. You have a 69 BB nova? Novas are very cool in my book have you ever checked out www.stevesnovasite.com? Lots of good info on Novas their. If there is anything I can help you with don't hesitate to ask.
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 #89       01-29-2007, 07:56 AM  
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Hi Gary,
Thanks, what kind of car is this in? Any pics?
 

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 #90       01-29-2007, 02:47 PM  
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Here are a couple!
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 #91       01-30-2007, 08:25 AM  
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Nice clean Nova! I'll see if I can find some pics of my 69.
 

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 #92       04-20-2007, 05:47 AM  
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Hello gents

I have been lurking on and off the last couple of months just tring to keep up with whats been going on around here. I have been pretty busy at work mosquito seasons just around the corner,lots of equipment to get ready. Enough of the B/S back to tuning carbs.
It is finaly warm enough to get the car out again. So after looking things over and some fresh gas I decided last week to take her for a spin. She felt kind of lean at cruise but I didnt think to much about it becase of the temp 50 deg. that day. Only out for maybe 15 min. and put her back in th garage.
Tonight changd the oil and pulled a couple plugs on th drivers side head. The plugs look ok maybe a little rich from idle I,m guessing. So I take it out to my secret test track and make a test run and things are not looking real good for some reason.
I have not touched the carb since the last time it was at the track in october. The car has sat most of the winter except to start it every couple of weeks to splash the oil around.
The first log is from last year at the track and the second log is from today. I dont understand how it can be so lean. Why does the AFR follow the RPM so closely now when it was'nt as bad in october? What do you guys think? where should I start my search?
Attached Files IRP 10-10-06 74 & 81 jets.log (180.3 KB, 152 views)
4-18-07 new O2 sensor (drivers side exhaust).log (225.9 KB, 131 views)

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 #93       04-20-2007, 06:49 AM  
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Hello Gary,

What kind of fuel was in it when it sat and have you looked at the fuel filter?
 

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 #94       04-20-2007, 07:05 AM  
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Quote:
Originally Posted by Tuner  
Hello Gary,

What kind of fuel was in it when it sat and have you looked at the fuel filter?

I think a mixture of BP 93 octane unleaded and some Cam 2 110 octane.

No I have not looked at the fuel filter. Will look at filter after work.

Thanks Tuner, how have you been? Any new projects you cae to share?
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 #95       04-20-2007, 05:07 PM  
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hello Gary; I notice the old log has a lot of miss fires under load and the new one doesn't.
What have you changed to do that?
Could you be using a better battery now?
Its better combustion from the miss fire point of view now so don't knock it, maybe you should consider the possibility that some of your rich AFR in the old log was from partially burnt fuels from weak ignition. Perhaps this is the true tune.  
 

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 #96       04-20-2007, 11:30 PM  
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Quote:
Originally Posted by shrinker  
hello Gary; I notice the old log has a lot of miss fires under load and the new one doesn't.
What have you changed to do that?
Could you be using a better battery now?
Its better combustion from the miss fire point of view now so don't knock it, maybe you should consider the possibility that some of your rich AFR in the old log was from partially burnt fuels from weak ignition. Perhaps this is the true tune.  

Hello Shrinker; The only changes to the car over the winter have been a new alternator and a new O2 sensor. The battery is still the same that was in the car last year. The missfire in the logs from last year seem to come and go. What I mean is sometimes their is more of them than at other times when logging.
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 #97       04-20-2007, 11:39 PM  
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Hi Gary,

I’ve seen “blends” of race fuels (which are usually blended with fairly large percentages of aromatics, toluene, xylene, etc.) and pump fuel (which is likely oxygenated?) make some interesting gum formations in fuel systems when the mixture sits for a few months. You might take a peek in the carb to see?
 

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 #98       04-20-2007, 11:55 PM  
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Quote:
Originally Posted by Tuner  
Hello Gary,

What kind of fuel was in it when it sat and have you looked at the fuel filter?

Hello Tuner; Check fuel filter at lunch every thing looks clean. Think my next step might be to take the carb apart and see if every thing looks clean inside. I know that there was good fuel pressure at the gauge on the last log, but I have no way to check fuel volume correctly. My gut feeling says the fuel pump so we will see.
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 #99       04-21-2007, 12:15 AM  
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If you've got pressure it's OK unless it's restricted downstream of the gauge.
 

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 #100       04-21-2007, 06:16 AM  
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Hi Tuner
Well after work I pulled the carb apart and had a look inside but didnt see anything out of the ordinary. All passages are clean and nothing seems to be gummed up. I decided to put every thing back together and go for another test drive.
My eye site must be going south about like the fuel pressure gauge needle is. I guess last night I wasnt paying enough attension to the gauge at the upper rpm range.
This is what I had for fuel pressure tonight.

RPM Fuel pressure

3000 5psi
4000 4psi
4500 3.5psi and still falling when I let off of the pedal.
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 #101       04-21-2007, 07:45 AM  
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OOPSIE on the pressure then eh!
 

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 #102       04-23-2007, 12:58 AM  
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Hello gents
Weather has been just about perfect here this weekend unlike the fuel system on the nova. I installed a new fuel pump yesterday afternoon. I attatched the logs also.
Session #1 is the old pump you have to go to 3.5 to 3.25 to veiw the WOT pull.
Session #2 is the new pump it seem to feel better by the seat-o-meter, the log looks maybe just a little better.
Session #3 is the carb after new jets. Left some notes in the logs. The jets in the first two logs are pri # 74 and sec # 81. the last log I went up on the jets they are pri #75 sec # 83.
Attached Files 4-18-07 new O2 sensor (drivers side exhaust).log (187.1 KB, 137 views)

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 #103       04-23-2007, 01:57 AM  
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Hi Gary,

Ah-hah….The old bigger jets make it run leaner trick. Must be a restriction in the fuel system somewhere? Dirty trick is when there’s an air leak on the suction side of the pump that’s above tank level and so doesn’t leak fuel (so you’d know it was a leak). Is it still the original tank and line, I forgot? Sock in the tank? Fuel cell foam in the phlogiston separator?
 

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 #104       04-23-2007, 02:15 AM  
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Hi Tuner
The tank is original but I replaced the 5/16 line. I replaced the original sending unit with one that has a 3/8 feed line along with all the hard line ( 3/Cool to the fuel pump. Yes there is a sock on the end of feed line in the tank. I have a piece of rubber fuel line (about 8" long) running from the sending unit to the hardline by the gas tank. Everything in the engine compartment is steelbraided line and -6AN fittings.
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 #105       04-23-2007, 02:29 AM  
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Hi Gary,

The rubber line at the top of the tank is a known offender. IN the 70’s when the gas changed it was a common problem. Leaks air in but not fuel out because it’s on top. It would depend if the hose you used were resistant to the stuff that’s been through it. Some race fuels with high percentages of aromatics are hard on regular black rubber auto parts store hose. Had a piece between the pump and carb on my own highway rig a few years ago that was only about a year old, pump gas only, smelled fuel and found it looking like a soaker hose leaking from little pin holes all over it.

Don’t just conclude this is your problem. You may have a fitting with too small a hole through it or a line pinched somewhere?
 

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 #106       04-27-2007, 05:32 PM  
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haha.

Good to see you guys back at it again!

It's hotrod season again!!!

Good luck Gary - hate to hear of problems "appearing" - but that's what usually happens to me too!  

My demon is still giving me trouble, too. I've toyed with putting the old Holley 750 Vac back on to see if it makes life "easier."
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 #107       04-27-2007, 11:27 PM  
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Quote:
Originally Posted by hotrodf1  
haha.

Good to see you guys back at it again!

It's hotrod season again!!!

Good luck Gary - hate to hear of problems "appearing" - but that's what usually happens to me too!  

My demon is still giving me trouble, too. I've toyed with putting the old Holley 750 Vac back on to see if it makes life "easier."

Hi hotrodf1: Yes still at it, just another problem to fix. Looks like a new fuel system time for the nova. what are you running for a fuel system on the camaro?
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 #108       06-04-2007, 04:06 AM  
Gary Geiger  
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New fuel system

--------------------------------------------------------------------------------

Hey guys

Well I went and did it now. I had a sump welded in the stock tank.Then ran all new fuel lines from back to front along with a new magnafuel pump. The new system is kind of overkill for this motor but I only want to do this once (hopefully). I now have a steady fuel pressure of 7psi thru all gears up to 6000rpm.
Here are a couple logs with the new fuel system.
Attached Files new magnafuel pump.log (429.2 KB, 132 views)

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 #109       06-11-2007, 05:47 PM  
hotrodf1  
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Quote:
Originally Posted by Gary Geiger  
Hi hotrodf1: Yes still at it, just another problem to fix. Looks like a new fuel system time for the nova. what are you running for a fuel system on the camaro?

I'm running the Mallory Comp 140 pump and bypass style regulator, 1/2" lines both to the motor and back, sumped fuel cell, Summit canister fuel filter before the regulator, Earl's screen type filter before the pump. I never have fuel problems with this setup. Rock solid always.  

Just got back from the Hot Rod Power Tour!  
Whew! It was great! HIghly recommended.  
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 #110       06-14-2007, 05:55 AM  
Gary Geiger  
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Hello everyone
I have been to the track 2 times this year just playing with the carb and the new drag radials. Last season the car ran a best of 13.41 at 103 on street tires, all the rest of the passes were in the 13.50 to 13.60 range.
This year has been very good so far. Last week the car went 13.17 and a couple 13.23 passes. Last night the car went 13.06 and a 13.07 not to bad for what the motor is. I would like to get this thing into the 12.9 range.
I need some help with the afr in these logs. The afr seems to act like a stair step,with each shift the afr leans more and more. I have tried going from .026 to .028 with the emulsion orfices with no luck. Then in session #3 of these logs I tried going from .026 to .025 on the HSAB, that seemed to do a little but I would still like to see this carb richer in second and third gear.
What am I missing on my setup? Where in the carb do I need to look to fix this.
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 #111       06-14-2007, 06:06 AM  
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Boy my memory is getting bad. I cant even remember something like post the freakin logs at the end of your post Here are the logs from last night.
Attached Files IRP 6-12-07.log (99.2 KB, 110 views)

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 #112       06-14-2007, 07:14 AM  
Tuner  
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Hi Gary,

Huh? It looked like the fuel pump and tank work helped a lot in your post 10 days ago. I compared it to an earlier log and it was richer at the high RPM with the new pump. Is it for sure that you have ethanol in the pump gas? Is it possible you have ethanol blended fuel one time and not the next? Is the weather hot so as to aggravate the tendency to vapor lock? Ethanol blended fuel has nearly a winter fuel distillation curve which is a bummer for a carb in hot weather. FI cars it doesn’t matter as much. Can you reiterate your bleed and E-hole set-up or remind me which post it’s in? Your old alternator was probably the source of most of the hash your logs had before. Did you happen to measure it for AC voltage it might have had in its output? The air to the carb is under-hood air through a regular open element filter, or?
 

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 #113       06-14-2007, 04:01 PM  
Gary Geiger  
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Hi Tuner,


Quote:
Is it for sure that you have ethanol in the pump gas?
Is it possible you have ethanol blended fuel one time and not the next?  

Yes I believe we have been out of attianment here and as of january 07 we have ethanol blended fuel.


Quote:
Is the weather hot so as to aggravate the tendency to vapor lock?  

The temps were in the upper 80's and pretty humid here.


Quote:
Can you reiterate your bleed and E-hole set-up or remind me which post it’s in?  

The e-hole in these logs are .028 (they have been .026 in all other logs)
The HSAB are .026
The IAB are .070


Quote:
Did you happen to measure it for AC voltage it might have had in its output?  

If my memmory is correct I think there was 32vac output.


Quote:
The air to the carb is under-hood air through a regular open element filter, or?  

Yes this is correct. The top of the air cleaner is a KN open element if that makes any since.
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 #114       06-14-2007, 05:36 PM  
hotrodf1  
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Quote:
Originally Posted by Gary Geiger  
Hello everyone
I have been to the track 2 times this year just playing with the carb and the new drag radials. Last season the car ran a best of 13.41 at 103 on street tires, all the rest of the passes were in the 13.50 to 13.60 range.
This year has been very good so far. Last week the car went 13.17 and a couple 13.23 passes. Last night the car went 13.06 and a 13.07 not to bad for what the motor is. I would like to get this thing into the 12.9 range.
I need some help with the afr in these logs. The afr seems to act like a stair step,with each shift the afr leans more and more. I have tried going from .026 to .028 with the emulsion orfices with no luck. Then in session #3 of these logs I tried going from .026 to .025 on the HSAB, that seemed to do a little but I would still like to see this carb richer in second and third gear.
What am I missing on my setup? Where in the carb do I need to look to fix this.


I used to have that problem as well, until I changed my fuel system over to the pump and bypass style regulator I mentioned. Did you use a deadhead style regulator or bypass?

For some reason, the bypass style on my car made a good difference in fuel pressure stability. But you stated earlier that you had solid fuel pressure, so that's probably not the issue. Tuner is probably in line with some partial vapor lock or something. I always wondered if I was seeing some of that as well when my AFR would flip to the high 14's all of a sudden - but it hasn't done that in a long time.

Good luck
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 #115       06-14-2007, 08:24 PM  
Gary Geiger  
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Quote:
Originally Posted by hotrodf1  
I used to have that problem as well, until I changed my fuel system over to the pump and bypass style regulator I mentioned. Did you use a deadhead style regulator or bypass?

For some reason, the bypass style on my car made a good difference in fuel pressure stability. But you stated earlier that you had solid fuel pressure, so that's probably not the issue. Tuner is probably in line with some partial vapor lock or something. I always wondered if I was seeing some of that as well when my AFR would flip to the high 14's all of a sudden - but it hasn't done that in a long time.

Good luck

Hi hotrod1
The pump and regulater are magnafuel (reg is a deadhead style). I do have steady fuel pressure at WOT or idle (6.5psi.).The one thing I have noticed At cruise say at around 40mph the pressure will toggle between 6psi and 7psi. I am not sure if this is a problem and have e-mailed magnafuel on this issue. I have done a little reading on a differant site on the return style reg. and that seems to be the preferance for the blowthru guys. From what I have read it looks like a good setup and I might end up switching to this in the future. What regulater are you runnig ?
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 #116       06-15-2007, 12:55 AM  
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Greetings Gary,

Had an experience on the dyno last week where turning up the fuel pressure made it leaner. This was a single 4bbl at 750hp with .120 Viton N&S. The AFR didn’t richen at the maximum RPM when the MJ was enlarged. The mid range was richer but the top didn’t change. Raising the FP from 7 to 9 lbs. made it worse. .130 steel N&S at 6.5-7 lbs richened the top to be in line with the mid. This was with (probably 10% ethanol, but I don’t know for sure) pump gas so vapor pressure of the fuel was ??? The dyno room environment was 70º fresh air and the carb wasn’t particularly hot like as if it were under a hood. The bowls measured 68º with a temp. pistol.
 

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 #117       06-15-2007, 05:49 PM  
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Quote:
Originally Posted by Gary Geiger  
Hi hotrod1
The pump and regulater are magnafuel (reg is a deadhead style). I do have steady fuel pressure at WOT or idle (6.5psi.).The one thing I have noticed At cruise say at around 40mph the pressure will toggle between 6psi and 7psi. I am not sure if this is a problem and have e-mailed magnafuel on this issue. I have done a little reading on a differant site on the return style reg. and that seems to be the preferance for the blowthru guys. From what I have read it looks like a good setup and I might end up switching to this in the future. What regulater are you runnig ?

Gary,

It sounds like the 6-7 psi that you are experiencing is pretty normal. It's basically the deadhead style regulator letting fuel in, then closing, then letting more fuel in, then closing, etc. when the engine is at low loads because of the low requirement for fuel. When you need more fuel (at WOT) it seems that the flow is more steady which makes for a more steady appearing fuel pressure.

I am running the Mallory return regulator #4309 see it here.
http://www.malloryperformance.com/Pr...minselection=4
**it even has the ability to vary fuel pressure based on vacuum/boost if need be. I haven't tried it yet, but it could be interesting. Not sure what conditions would make it work best as my motor is NA.

I think the bypass style is the way to go no matter what. The pump is no longer cavitating on that fuel when you are at low load / cruising conditions. With the bypass system, I think it's easier on pumps, keeps the fuel cooler, and supposedly provides better performance in a drag racing setup where you are forced to fight the G-forces at launce. The deadhead system had to get all that fuel moving at once after you launch whereas the bypass style system already has the fuel moving and ready to fill the carb as needed. And the fuel doesn't stay up in the hot engine compartment for long either.

With that said, I'm sure your deadhead system will work fine. Just keep an eye on things if you do extended cruising.
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 #118       06-16-2007, 06:18 AM  
shrinker  
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Hello Gary; I agree with hotrod f1, the bypass system design is the only way I go. The electrical load is greatly reduced, the pressure stability is far superior, the fuel doesnt heat up and vapor lock in the pump. When you launch with a bypass system the g-force in the return line matches the flow line and there is ideally no change in pressure at the carbs. You pump is large for this engine so it should have no problem keeping the return line full. When the return line is not full its not as accurate but if the bypass valve is located at the forward most point of the fuel system of the car then it can still shut off and reg the pressure quite good even with a pathetic pump.
Any problems people have with bypass design is poor regulator function or low flow pumps or too small return lines.
 

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 #119       06-18-2007, 06:53 AM  
Gary Geiger  
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Hey Guys,

I took some time to play with the carb today and found something strange to me. I have not been doing this long enough to know if this is a carb issue or a motor issue. I am going to set these logs up with the orfice sizes that are in the carb.
CARB
Jets Pri 73
sec 80
IAB Pri .070
sec .070
HSAB pri .026
sec .026
IFR pri .032
sec .032
E-hole #1 .026
#2 .026
#3 Plug
The first log is with the o2 in the right side exhaust pipe,and the second is in the left side. The fuel in the car is the same in both runs. The runs are about 1/2 hour apart. What do you guys think? Any ideas or help would be great.
Attached Files 6-16-07 test right & left side exhaust.log (134.0 KB, 143 views)

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 #120       06-18-2007, 01:14 PM  
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Hi Garry,

My first thought is exhaust leak. Was dealing with exactly this on a dyno last week. The collector leaked on one side (1357) and it was reading lean about like yours. Sprayed a little carb cleaner at the leak and it sucked it in and richened the reading

Your plug pics in post #77 look like there might be more rich cylinders on the 1357 side, but a closer look at new plugs would be a good idea. Can you make some WOT passes on a set of new plugs and read them?

I forgot which intake you have. RPM Air Gap? Is it the one with the center divider cut down between the upper and lower halves? If it is (and you don’t have any exhaust leaks causing the left & right sides to be different) it’s likely that stagger jetting is going to be necessary. A spivy can be used to steer fuel into a lean cylinder. Like Robin Hood, take from the rich and give to the lean. The trick is to figure out which cylinder is going hungry and which is being greedy.

A pal of mine has an RPM Air Gap on a ZZ4 crate motor with a 750 Holley and I remember it was plug-fouling rich in one cylinder on the right side, either 4 or 6, I think. I recall it was a middle hole on the even side, but I don’t remember which for sure. In that pic, yours looks rich in 2, but new plugs with a higher ratio of WOT time would be more revealing.
 

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 #121       06-18-2007, 02:47 PM  
Gary Geiger  
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Quote:
Originally Posted by Tuner  
Hi Garry,

My first thought is exhaust leak. Was dealing with exactly this on a dyno last week. The collector leaked on one side (1357) and it was reading lean about like yours. Sprayed a little carb cleaner at the leak and it sucked it in and richened the reading

Your plug pics in post #77 look like there might be more rich cylinders on the 1357 side, but a closer look at new plugs would be a good idea. Can you make some WOT passes on a set of new plugs and read them?

I forgot which intake you have. RPM Air Gap? Is it the one with the center divider cut down between the upper and lower halves? If it is (and you don’t have any exhaust leaks causing the left & right sides to be different) it’s likely that stagger jetting is going to be necessary. A spivy can be used to steer fuel into a lean cylinder. Like Robin Hood, take from the rich and give to the lean. The trick is to figure out which cylinder is going hungry and which is being greedy.

A pal of mine has an RPM Air Gap on a ZZ4 crate motor with a 750 Holley and I remember it was plug-fouling rich in one cylinder on the right side, either 4 or 6, I think. I recall it was a middle hole on the even side, but I don’t remember which for sure. In that pic, yours looks rich in 2, but new plugs with a higher ratio of WOT time would be more revealing.

Hi Tuner,
I will pick up some new plugs today. The intake is an RPM Air Gap and the center divider is cut down between the upper and lower halves. I will look for a exhaust leak as well.
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 #122       06-20-2007, 12:13 AM  
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Hi Gary,

Looking for header leaks I used LogWorks in the real time mode and sprayed the carb cleaner at the leaks. The AFR darted around just like spraying in the intake. Tried it at a few different RPM’s but it did it pretty much the same every time. The leak was where the pipes enter the collector. This was in a dyno environment with lots of fresh air moving through the room and a fire extinguisher handy. (Due care advisory and disclaimer, etc, etc.)

--------------------------------------------------------------------------------
Last edited by Tuner; 09-30-2007 at 06:33 AM.
 

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 #123       07-05-2007, 02:56 AM  
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Hey guys;
I finally made it back to the track to make some more passes. Tuner I think you may be correct on the header leaking air on the drivers side. I have not been able to prove the leak with brake clean but have not had a lot of time to play lately. Here are some pics of the plugs. The plugs are B8ES and have 4 passes on them and 4 trips back to the pits. What are your thoughts?


--------Right ............Left
Jets Pri 70 ...............72

Jets Sec 75................77
Attached Images plug caps 7-3-07 002.jpg (75.3 KB, 230 views)
plug caps 7-3-07 003.jpg (80.4 KB, 203 views)

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 #124       07-05-2007, 05:00 AM  
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-Initially to me they look way rich.

-I feel that wide black ring is showing you excess fuel at wide open throttle when asking for maximum power.

-If you take some spray carb cleaner----spin the plugs in a lathe and wipe the carb cleaner onto the porcelain that should remove most of the black residue---then look at the width of the black rings.
---------------------------------------------------------
-The intensity of the darkness---darker and more profound----means those cylinders are making more power than the lighter colored and less profound rings.

-In general they actually look pretty good where they are white.

-I like to see the rings with a nice & profound darkness---and the ring widths such that you can get a measurement with the tips of dial calipers---and work the WOT fuel down to where you have about .040" to .060" ring widths on all the plugs.

-When you get caliper readings then note those in relation to the cylinder numbers and see if that tells you anything.
----------------------------------------------------
-Sorry to say but I haven't been following this thread---don't really know all the details of what's been done---but in my world those are way rich at WOT for ANY application or ANY fuel.

-When I say WOT fuel---I would typically trim with lowering the float levels, less fuel pressure if you are well over 5psi at WOT, maybe modify the bowl vents or vent whistles, take a closer look at what ever you have on top of the carburetor, then maybe change to smaller power valve restrictions.

-One other serious consideration is the brand of fuel and or additives you are using---and a lazy ignition system can be playing "rich" tricks on you.
 

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 #125       07-05-2007, 08:24 AM  
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Hi Gary,

Good to hear from you, glad to hear you’re getting some track time in.

When you say “brake clean” that makes me nervous. Read the label on the can and be careful about getting anything with chlorine in it (trichloroethylene, tetrachloroethylene, etc.) mixed up with a running engine (or any hydrocarbon flame for that matter) because phosgene, a deadly gas, is formed when the chlorine and CO combine. http://en.wikipedia.org/wiki/Phosgene

I agree with Bill Jones, they look rich, but they’re also a cooler heat range than they need to be for drag racing your engine. Probably be OK for road racing. Brodix’ advice to use the 8 is to err on the side of safety for hard WOT use of longer duration. I think a NGK 6 is OK in this case.

So, the dilemma is obviously which side of the engine to believe. I think the plugs look consistent with what I would expect with a low 11/1 AFR. #2 and maybe #3 look like it (they?) didn’t get as much fuel as the others and they are on the same venturi so keep an eye on that for a possible location for a larger jet or PVCR when you get closer to the sweet spot. Which cylinders do the carb venturi feed? The leaner primary (choke side) is feeding 2 & 3, right? Throttle side feeds 1 & 4?

Your previous posts with the sensor in the driver’s side collector show the lean (14/1 approx.) WOT. http://www.i***em***s.com/f...7&postcount=92

Whatever you had going on in this picture http://www.i***em***s.com/f...8&d=1151074281 for jetting is close to OK, but the plug is either a little hot or it’s a little bit lean, but not bad. The dark ring with clean porcelain below it is what you’re looking for. With the plug in this picture, a cooler plug or a richer mixture will move the ring toward the tip. In a post near the one with that plug, you said the mixture was 12/1 so dropping a heat range would be the choice. What was the heat range of the plug in that picture?

You’ve been swapping sides with the O2 sensor occasionally in this deal, I bet huh?

What size is the PVCR?
 

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 #126       07-05-2007, 03:02 PM  
Gary Geiger  
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Quote:
Originally Posted by Tuner  
When you say “brake clean” that makes me nervous. Read the label on the can and be careful about getting anything with chlorine in it (trichloroethylene, tetrachloroethylene, etc.) mixed up with a running engine (or any hydrocarbon flame for that matter) because phosgene, a deadly gas, is formed when the chlorine and CO combine. http://en.wikipedia.org/wiki/Phosgene

I will look into this.


Quote:
So, the dilemma is obviously which side of the engine to believe. I think the plugs look consistent with what I would expect with a low 11/1 AFR. #2 and maybe #3 look like it (they?) didn’t get as much fuel as the others and they are on the same venturi so keep an eye on that for a possible location for a larger jet or PVCR when you get closer to the sweet spot. Which cylinders do the carb venturi feed? The leaner primary (choke side) is feeding 2 & 3, right? Throttle side feeds 1 & 4?  

If I understand your question correctly the (choke side) is feedind 2 & 4 and the throttle side is feeding 1 & 3 .




Quote:
Whatever you had going on in this picture http://www.i***em***s.com/f...8&d=1151074281 for jetting is close to OK, but the plug is either a little hot or it’s a little bit lean, but not bad. The dark ring with clean porcelain below it is what you’re looking for. With the plug in this picture, a cooler plug or a richer mixture will move the ring toward the tip. In a post near the one with that plug, you said the mixture was 12/1 so dropping a heat range would be the choice. What was the heat range of the plug in that picture?  

I will have to check my notes on the plug heat range.



Quote:
You’ve been swapping sides with the O2 sensor occasionally in this deal, I bet huh?  

Here are the logs from the other night at the track. Sorry I forgot to post them in the last post. Sesssion 1 & 2 are the drivers side and 3 & 4 are the drivers side.


Quote:
What size is the PVCR?  

I have not done anything with the PVCR so it is still the stock calibration. What size set screws do I need to make this adjustable?
Attached Files IRP 7-3-07.log (68.6 KB, 127 views)

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 #127       07-05-2007, 08:21 PM  
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-one side of the carburetor on a Chevy predominately feeds cylinders #1-4-6-7 and the other side feeds 2-3-5-8---I don't know which side feeds which combinations of cylinders--but ALL V/8 180 manifolds feed a front and a rear cylinder from one side of the engine and two center cylinders from the other bank.

-This needs to be kept in mind when tuning because at WOT you can effectively tune about two cylinders at a time with one single jet change---like cylinders #2 & 3 can be richened up with a front jet change on the side of the carburetor that feeds the plenum that serves 2358---and 5 & 8 would be affected by a rear jet change on that same side of the carburetor.
 

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 #128       07-06-2007, 05:17 AM  
Gary Geiger  
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Quote:
Originally Posted by billjones  
-one side of the carburetor on a Chevy predominately feeds cylinders #1-4-6-7 and the other side feeds 2-3-5-8---I don't know which side feeds which combinations of cylinders--but ALL V/8 180 manifolds feed a front and a rear cylinder from one side of the engine and two center cylinders from the other bank.

-This needs to be kept in mind when tuning because at WOT you can effectively tune about two cylinders at a time with one single jet change---like cylinders #2 & 3 can be richened up with a front jet change on the side of the carburetor that feeds the plenum that serves 2358---and 5 & 8 would be affected by a rear jet change on that same side of the carburetor.

Hi Bill;
Thank you for clarify'ing what Tuner was trying to get me to see. I have to admit that you guys have educated me on this subject today. I assumed ( which always gets me in trouble ) that the drivers side primary jet feeds cylinder #1 & #3 and the secondary jet would feed cylinders #5 & #7. After looking at the picture of the plugs again I understand why the ones that are richer are in the cylinders they are in.
So again let me say THANK YOU to you both for the education.
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 #129       07-06-2007, 10:43 AM  
Tuner  
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Hi Gary,

This is easy, just run the right side of the engine.  I use 10-32 x 3/16” brass socket set screws for PVCR jets. You have to be very careful to tap the threads to exactly the right depth so that the screw is in far enough to not interfere with the power valve and not so far in as to intrude into the main well. If the data from the right side of your engine in the last logs is accurate it looks like the WOT is pretty good. Are your headers the kind that slip fit the primary pipes into the collector? You need to figure out if any leaks are messing with things here. Because headers change shape with heat variation the leaks aren’t consistent, which just makes matters more confusing. Put the AFR meter where you can see it while you spray carb cleaner (no chlorine – some carb cleaners contain methylene chloride or dichloromethane – watch out) at the suspected leak and watch the meter. A couple of weeks ago when I did that it jumped toward rich just like it was sprayed in the intake.

If your PVCR is the original .059” (as per BG’s wbst) I think all you have to do is use a smaller PMJ and perhaps a smaller SMJ. Based on the logs of earlier posts where the WOT is near 11.3 I would have said lean it some, but the last log is very near 12.5 at WOT on the “good side” so ???? Play the jet up and down a little to the time slip. Did you get in the 12’s? Perhaps the AFR differences in logs with the sensor in the same side are due to ethanol added fuel or not?
 

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 #130       07-06-2007, 03:02 PM  
Gary Geiger  
Registered User   Join Date: Mar 2006
Location: INDY
Posts: 112  

Quote:
Originally Posted by Tuner  
Hi Gary,

Are your headers the kind that slip fit the primary pipes into the collector?

Yes and they are fully welded at the collector. I suspect this is where the leak is though.


Quote:
You need to figure out if any leaks are messing with things here. Because headers change shape with heat variation the leaks aren’t consistent, which just makes matters more confusing. Put the AFR meter where you can see it while you spray carb cleaner (no chlorine – some carb cleaners contain methylene chloride or dichloromethane – watch out) at the suspected leak and watch the meter. A couple of weeks ago when I did that it jumped toward rich just like it was sprayed in the intake.  

Good news on the can of brake clean it has no chlorine. I will have to do some more leak tests on the headers. The firsts tests were done just at idle. I will try bringing the RPM's up and retest them.


Quote:
If your PVCR is the original .059” (as per BG’s wbst) I think all you have to do is use a smaller PMJ and perhaps a smaller SMJ. Based on the logs of earlier posts where the WOT is near 11.3 I would have said lean it some, but the last log is very near 12.5 at WOT on the “good side” so ???? Play the jet up and down a little to the time slip. Did you get in the 12’s? Perhaps the AFR differences in logs with the sensor in the same side are due to ethanol added fuel or not?  

After looking at the plugs from the last trip to the track I'm going to have to beleive the right side of the motor. I had the right side set at PMJ 70 & SMJ 75 . I will square the jets up to 69 in the front & 74 in the rear and try a set of B6ES plugs. Also try fiddling with the fuel pressure and float levels.

No 12 sec pass yet! The car went 13.06 and backed it up with a 13.07 four weeks ago. I can taste the first 12 sec pass just not there yet.  
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