So as some of you know I picked up Jim's (amx1397) old exhaust a few months back. Added an H-pipe for less pop and better flow. So I took it to the track and didn't see really any gains with this "bolt-on". Well after getting an AFR reading done to it I can see why....the damn thing is all over the place between 4k and 6k RPMs. It's actually robbing us power without a proper tune


WHP: 313hp

Bear in mind that I was pulling a solid 12.0 (5k-6.25k) after I got my initial ECU tune w/ a Code3 pulley when we had our Tuning GTG in Miami in January. So with the extra exhaust flow the ECU is really undercompensating. So it looks like that even if you want to mess around with the exhaust, be prepared to get your ECU re-tuned.

I sent my ECU to Jerry to get the tune fixed up over the weekend and I expect it back on Wednesday. I'm hitting the track Thursday if it stays dry and I'm going to try and get the car re-dyno'd on Friday.

I don't know of anyone who's done a custom exhaust and posted before and after times, but without the retune, the best I did was a 12.5x with those AFRs being all over the place