I am rebuilding my 91 Z28 and I want to keep the motor pretty much stock. Im putting a mild cam in it, a little bigger than stock and plan on working on the plenum and TB. I was wondering if there is anything to gain on tuning the PROM yourself, versus the stock GM setup??? I am a computer programmer by day, and I must say Windows is ALOT better by tweaking it a "little" So, I was wondering if there are mess-ups so to speak in GM's codes. I have downloaded WinBin, and have a good laptop, but Im having trouble finding the cable I need to hook up the laptop to the diagnostic port.?? The cam going in is basically a TPI grind(.475/.490)....not too big, just good enough. I also have a 2800stall lockup converter, and a adj fuel reg. going in. It would seem to me with the power range changing from the cam, and increased fuel and air, the ecm would only compensate so much from the codes it has.....right? Any advice on this subject would be greatly appreciated. Thanks

 

GM designs the calibration for the average citizen, and the EPA.

A little more cam, means, the VE of the engine has moved. The ecm has no way of tuning for torque just AFR. So the timing and fuel will be off.

Just on the above two areas, should say to you, well i can go with close, or correct.

Me?.
I go for correct, and to match my driving style.
And the ego statisfaction of knowing it's my tuning that makes the car so neat to drive.

 

IS there anyway to tune for better performance, AND pass emissions? The VE tables are the vacuum, correct?? I can understand how that would change with higher lift. Also, isnt there a way to redo timing in the PROM itself? (instead of turning the dist) I have just read the article on here about prom tuning, and it seems pretty complicated, even for early 90's technology....I just want to squeeze all I can out of the PROM, because it seems to me, if you have the most powerful engine in the world, and the ecm cant control it, what good does it do ya???