Good idea?


Aug 1, 2008
I currently have 55 lb injectors in my engine and an Accel GEN7 ECM. Last year (with a cat converter) by tuning A/F and spark, I was able to pass emissions at 15 and 25 mph on a rolling dyno. It was pretty tough, but I did it.

I was thinking that when I have to do this again some day, maybe I should change to 28 lb/hr injectors and of course re-adjust the GEN7 to accomodate the change. Was wondering if the smaller injector would conceptually make it easier for me to tune to pass. Whaddaya think?
It depends if the Base PW is less than the injector opening dead time, then the injector may be a little it erratic in spray pattern. Otherwise I don;t think its going to make much difference. Are you using a wideband o2 on the car?>
PW with 55 lb injectors at idle is only 1.2 ms I think, sometimes going to 1.0. I will have to confirm that number when the weather warms up enough to start and drive the car again.

Yes, currently using an AEM 30-4100 wideband gauge controller in closed loop with the GEN7. I am not all that happy with the AEM setup and plan to replace it with an Accel wideband soon. A/F on that guage at idle looks something like 14.2, 14.3, 14.2, 14.2, 14.3, then out of nowhere it jumps to a single reading of about 16, then back to 14.2, 14.2, 14.3, etc. Seems to have that wacky lean reading about every 8th or 10th display. I can't explain that. Maybe there is a feedback loop/incompatibility with the GEN7. Also, the AEM gauge may read 14.2, but the output voltage from it does not match. So there is an offset or difference of 0.2 A/F ratio between what the gauge says and the Accel Gen 7 reads. I called AEM about it. They said that was typical and suggested that I buy an AEM DFI ECM setup because you can adjust the offset. Sure..!