Tuning issue

Stroked383 · 02-12-2010, 12:48 PM

Hoping someone might be able to provide some insight on a tuning issue I'm having with my 87. We've changed the motor to a 383 stroker (provide details below). Having an issue with the car running very rich at mid-range rpm (AFR of less than 10:1) and leaning out at WOT (14:1). using OEM setup with a chip programmed from TPiS.

383 stroker,10.4:1 compression,

AFR 195 CC Aluminum cylinder heads,

Comp. Cam (#08-503-8),503/ 510 lift (1.6 ratio rockers) 224/230 duration, 112 lobe separation,

Weiand (7540) Intake Manifold with Holley Fuel Rail and 30 lb. Fuel Injectors with 50lbs Fuel Pressure

Luckily it is -10 degrees in Canada right now and can't drive the car for at least another 2 months

Look forward to any input.

bjankuski · 02-12-2010, 01:12 PM

Is the chip programmed for the 30LB injectors it appears to me that it is not? You need to adjust the EFI program, there is nothing that can really be done without changing the program. The car is rich at low RPM and lean at WOT, a bad combination.

Without seeing the program my guess is incorrect injector constant, MAF tables need adjustment, and PE tables need adjustment. Fuel pressure should also be lower to mid 40's.

383vett · 02-12-2010, 05:24 PM

I was running pretty much the same combination, 383 with the same cam, compression, and injectors. I was running a SuperRam and Holley 20 degree heads. This combination was good for low 11's in my car. I would suggest using and aftermarket fuel management system. I used and Accel gen 6. Might think about a gen 7. You will be able to fine tune and perfect your combinaton with a laptop without having to burn chips. Willie