This is on a 2.7, 3" jbp header back exhaust to a stock muffler, 45-50* temps outside, meth off.

The MAF is copy pasted from the GM stg 2 tune: ACTUAL AFR = 11.6-11.8

208 kpa, 15.x psi



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This is when I ran a 2.9 w/ the stock exhaust manifold, stock dp, 2.5 catback, no meth.

MAF was exactly the same as my current tune on the car, shown in the log shot above.

KPA 203 or 14.74 PSI




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By dropping to a 2.7, is my g/cyl really supposed to raise that much? According to a local tuner, I have excessive pressure. But I am no longer blowing the dipstick. And the comp. test was a pass both times I checked.

Another question... you'll notice in the top screenshot my timing at WOT is 13*, when in the editor Im commanding 18*; why am I only seeing 13*?
I'm not seeing any knock at the top of the pull; so I don't think it could be spark decay taking away timing....? CONFUSED...

Thanks

 

OK, now this is just comedy. For a TUNER to say you have excessive cylinder pressure without knock. No significant way to make more power without more cylinder pressure. Compression / leakdown tests aren't a conclusive indicator of engine health. These mid/high 100's psi is nothing compared to what these cylinders see when there is actual combustion taking place.

 

It all in the way your maf is calibrated, on the 2.5" i was at 1.46 g/cyl on the tvs i was in the 2's

 

Thats what I thought to.. Though the local tuner has the same maf as me. We're both running the GM stg 2 maf. Only differences in our setup are a 2.8 pulley, and a header(im on jbp he' has the zzp mid length).

He's seeing g/cyl topping in the 1.04 cell range like my 2.9 pulley.

I'm gonna guess the 2.7 creates :that much more: g/cyl, compared to a 2.8 or 2.9 pulley. Wonder what meth will do when i turn it on...?

Last question...

Why is it I'm seeing 13* of timing in my log, when in the "EDITOR" under high octane spark advance I inputted 18* of timing in the same cell range.

 

Does the high octane map tale off in the higher g/cyl to 13 or does it carry it tell the bottom right of the table ?

 

I'll pull up a screen shot. hold tight

 

your high octane and low octane tables have to match to obtain the timing you want to run. blame gm's octane sniffer for this one.

your g/cyl is fine.

 

I'm chiming in because I'm curious and don't know much about tuning yet.

What exactly is the g/cyl? Is it a measure or pressure inside the cylinder?

 

grams per cylinder in a nut shell

 

Will do, I'll just do a quick copy paste when I go out and finish tuning the car.

Thanks for the info on the g/cyl

Been having a ever so slight oil leak from the valve cover gasket on the passenger side. Since I solved the dipstick popping issue by undoing the bolt connecting it to the intake manifold, I believe that ruled out the possibility of excessive crank case pressure...

After A QUICK look at what gasket we use to mate the valve cover to the head... I'm surprised it held up for 30k of abuse on a aggressive tune.

New valve cover gasket is due to arrive some time this week... slight delay thanks to the holidays and the weekend.

 

steve, the valve cover shouldnt really have any excessive pressures exerted on it. And a thick rubber gasket is pretty damn strong.

 

explain why mine decided to give in one area... my car is just weird...

 

i figured you knew that much alrready...lol

 

quit rubbin it in lol

im still quicker than your s/c 2.2

 

maybe..... maybe only with meth...who knows...
....we need to race already!

 

Told ya to bring it to the track; I'd love to see the 60's you can pull on that auto.

I keep changing my cars power; in fact at the momment I dunno where its exactly starting to make a decent amount of trq.

we'll go to mexico and give it whirl