Exactly.
Higher than normal boost, lower than normal power, there's a restriction in the exhaust flow somewhere.

Could be anywhere from the tips to the Cam, start at the exhaust and work your way in.

 

Cat being replaced by straight pipe right now. With this being a track only car, it makes no sense having a cat anyways. Don’t ask why I purchased it lol. Once it’s out, back in the dyno it goes.

 

If it has a muffler or resonator pull that as well. Gained +10 HP just removing the muffler and running with straight pipe back from header. Car has race muffler just good enough to make noise limit.

 

Interesting. I have a race muffler on it now but has v-band clamps. I’ll ask for a dyno run with muffler on and off to see the difference. It’s already loud as hell with it and the cat. I can’t imagine the noise with no cat and no muffler. Who cares. Lol. Only track I know that I’d drive to and has a decibel limit is Laguna Seca. Thanks.

 

Been busy, but got an update. Cat removed from RMW street header setup. With just cat removed, boost now sits low at 15psi and gained 14 rwhp. Now time to start to see what can be squeezed out of this thing.

 

Well that made quite a difference!

 

I have The RMW BVhead, grand Am Cam, 17% Craven pulley, shorty header and Milltek cat back. I see 15.5psi at peak. I have the RMW canned tune on my recent 2k mile short block k1 rods, Wiseco forged pistons, king tri metal bearings and OEM main bearings on a balanced crank.

 

Final numbers and held back by intercooler efficiency.
233.1whp at 14psi.