about two months ago i installed new 26# injectors in my 91 l98 camaro. they were sold to me as 22# injectors (mislabeled). i am in the process of installing an AFPR and was wondering if prom program is necessary

car is pretty much stock with only some exhaust work being the only real upgrade (besides the bigger injectors)

 

The AFPR might help you some, but yeah, what you really need to do is change the injector constant setting in your prom chip if you want the 26's to work properly. Without changing that setting in the chip, your pulse width will never be correct with the computer thinking it's controlling 22's instead of 26's.

 

Run the numbers on your injectors, there are 2 types of lS1 injector, a 28 pound at 4 bar, and a 25 pound at 4 bar. TPI's run 3 bars of fuel pressure so the 25 pounders run closer to 22 pounders, and the 28 pounders run closer to 25 pounders. BTW a bar is 14.7psi, 3 bar would be 14.7 X 3 = 44psi, 4 bar would be 14.7 X 4 = 59