[tur·bo·charged]

anybody know if replacing the stock downpipe with an RMM will be sufficient enough to run 18psi or does the stock cat-back exhaust need to be replaced also??

 

[nito822]

I could get up to 20psi with the RMM and stock cat-back.

 

[Josh S]

I have the stock cat-back and a RMM DP and I hit 22psi before. I can hit 18psi+ without a problem, although the stock cat-back does cost me some power. I usually run ~113mph traps, I took the cat-back off and ran an open DP at the track once and ran 116mph traps, so a free flowing cat-back defently will give some power over stock.

 

[WayneCar]

The stock cat-back flows fairly well. I ran an
[email protected](with a 1.68 60' time) with the
headlight in. The next week I came back with
the headlight out and a Greddy SP cat-back and
my mph improved to 119.25. Probably picked up
~20 hp from the cat-back. This was on 19-20 lbs boost.
Wayne

 

[tur·bo·charged]

all right so the consensus is that the stock cat-back is ok for around 18psi, but begins to restrict horsepower at higher boost?