whats the leanest cylinder?

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71gtdart

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on a 408. I would guess it would be 1,2,7, or 8 just because they are farther away from the carb. intake is a Air Gap if that helps.

need to get my EGT installed.

thought about shooting each header pipe with a temp gun at idle to see which was the leanest, but that could change at high rpms i guess.

I'm just asking to see if there is a pattern based off of what cylinder you guys have yours on.

thanks for any input.
 
Whenever I have seen issues in my nitrous stuff it's on the corner cylinders. This is with large single plane intakes though so I can't be certain about your application
 
thats what I would think since they are farther away, but I'm not sure how the divider in the Air Gap affects the distribution.
 
Yeah that's the part that loses me. I have zero experience with that intake.


Git you some big stuff!!
 
nah, ain't into all the maintenance and $ that goes with the "BIG STUFF".

I like something that goes high 6's (1/8th) and the only maintenance is adjusting some valves and changing fluids.
LOL, don't take much to please me. bracket racer with a glide!!!! LOL, be nice!
 
I just read in muscle car mag about new cams they came out with. I think it is comp cams is now making a 4 profile cam. The outboard cylinders 1,2,7 and 8 have more duration on intake and exhaust than 3,4,5 and 6 to balance fuel to all eight cylinders.
 
Since the air gap (and regular RPM) are dual plane intakes with each cylinder fed from 1/2 of the plenum and out of sync from the last cylinder there's not much fuel distribution problem. Also, due to it's design the middle cylinder runners are real close to the same length as the end cylinders because each middle cylinder is fed from the opposite side of the plenum, unlike a single plane. For that reason I don't think it's possible to predict what the leanest cylinder would be. That would depend on the flow characteristics of the heads (unless all ports are equalized some ports can flow a great deal more than others) and if there are any casting flaws with the intake.
 
I can tell you that the cylinder that exploded due to lean detonation in my Barracuda was #8. It gets my vote!

Nasty things happen when the rod and piston falls out of the block too. :eek:ops:
 
on the stock car engines we ran into the opposite ,cylinders overheating because of poor cooling #4/6 and 3/5 even with the mods done .the coolant pushes around the center cylinders to quickly, so we cut .015 off the tops of the 4 pistons, to get them running at the same temp/fuel .on a street engine this would be help full .but not for a drag engine. our failures were in the middle cylinders mostly exhaust valve problems, swelling up of the stems and dragging in the guides and we removed the stem seals on the exhaust valves to help cool the valves, never had smoking issues ,you couldn't tell there were no seals. and the exhaust lobes of the camshafts were wore down from the tight guides when the engine went lean.
 
I think historically I've always found 7,8, or 2 to be leanest. Not always the same port...
 
67cudafb said:
I just read in muscle car mag about new cams they came out with. I think it is comp cams is now making a 4 profile cam. The outboard cylinders 1,2,7 and 8 have more duration on intake and exhaust than 3,4,5 and 6 to balance fuel to all eight cylinders.
Click to expand...



you could try tightening up the valve lash on the .outboard cylinders
 
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