Ok heres the deal we have been struggling to get this thing to work now for the past 5 weeks to no avail. Just yesterday we got the car to be consistent, It had 2 clean and prefect pulls when the car was cold, when the car warms up the graph just falls to ****. What I mean by that is we loose about 30RWHP and 50RWTQ between the 3500-3600 range and the power just keeps falling off to the point where the car is making less than 200RWHP and the car fells extremely sluggish. In the 2 runs the car ran great it pulled over 400RWHP and we didnt even do a full run(shut it down at 4000 1st time 5200 2nd time) And you can just feel the difference in the car between the 2 runs. The car is on a wideband dyno the A/F in constant 12:1 across the whole range, timing is good(around 31) and there is no knock. We changed all the plugs and wires, replaced the coil, replaced the opti, re-checked the connections to the igntion box, and re-checked all the grounds. The car runs incredibly smooth, doesnt stutter,stumble, none of that stuff. The MAF was showing constant readings within the operating perameters. The car does have the stock "cat" on it, and though it is a restriction we dont think that is the main problem. We are going to drop the exhaust and run open headers tommorrow to see if that fixes it, but the car doesnt seem to exibit any of the signs of a clogged cat, besides I wouldnt see why the car would work when its cold and than crap out when its warmed up. So my question is what the F*@# is causing my problem?! Heres the list of stuff done to the car, hope one you of guys can figure this nightmare out..

95 Z28 M6
AFR Ported LT4 heads 2.02/1.60 valves
LT4 Intake Manifold
30lb Fuel Injectors
Centerforce Dual friction clutch
CC 224/ 236 blower cam
GM extreme duty timing chain
Pro magnum self-aligning 1.6 rockers
Compucar wet nitrous kit 75-150HP
Custom PCM tuning by ED wright
Powerdyne 6lbs. Supercharger
MSD6AL ignition with BTM
AS&M 1 3/4 headers and AS&M 2 1/2 Y-pipe
Borla 3" cat-back exhaust

 

Sounds to me that it is in the PCM tuning. When the motor goes to close loop the PCM is telling it to do something it isnt suppose to do. My son is working on his ATI supercharger now and we have the same exact problem! It is on a diff motor but we are learning to burn our own proms for his computer. Its a 92 305 Chevy with TBI.
If air /fuel ratio stays good then I think it would be prolly something to do with the PCM.

Dave

 

Thanks Dave, if dropping the exhaust system doesnt fix the problem today, I'll have to go back and re-evaluate the tuning. The worst thing is Ed just wont tell me if they changed anything in those fields. He always like look at this or look at that and tha has been getting me nowhere fast! I talked to one of the guys over there and they said that it shouldnt matter because once the car goes WOT hot or cold its the exact same loop. So it shouldnt run right sometimes and not the next. It just doesnt make any sense at all <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />