Mikegpr03

I'm currently running an OE tune file, my car was coded so that my obd2 won't go off giving me a CEL. I planning a nice manifold back 3' stainless ( by passing all 4 cats ) into a dual in and dual out muffler with internal X pipe right into the stock mufflers. Essentially the third muffler will go in place of the factory resonator to eat up some of the sound and rasp. What REALISTIC numbers are to be expected when removing a 4 cats and already having a tune. I'm currently at 433 @ the wheels.

Thanks
Mike

Mikegpr03

Guys please don't rush to reply LOLOL

xtyper

I would expect about 20whp gain by removing all cats and leaving stock log exhaust manifolds intact. All else equal, that should put you around 450whp, but I would highly recommend redynoing ASAP after the mod to make sure the AFR curve wasn't adversely affected.

Good luck!

dodger63

Connecting to the stock exhaust manifold?

jacob502

Removing all four cats and and keeping the stock log manifold, will give you 25-35HP.
replacing the secondary cats with an Xpipe will add 5-10HP

installing a full-length headers or LT headers and removing all of the catalytic converters will gurantee you 50-55RWHP on a dynojet. add an Xpipe and that 55-60HP.