I'm heading to my shop at college and will have plenty of time to weld up flanges and 2.5" pipe for one, will I see any gains? BTW I put this in this forum because I only want to hear from boosted people. I'm running a Star kit w/ 1g SMIC and 2.5" exhaust w/ hi-flow cat so I do have a slightly larger DP then the HRC guys, but will the notice be worth the time to make it?

Well do you already have a 2.5" exaust system already? It sounds like you will be making one. If that is the case I would go 3 inch. if not then I say put it on and see for yourself. It is going to help exaust flow better that even a high flow cat.

Well I wasn't sure to get 2.5 or 3. I thought 2.5 would be consistant in the flow of the exhaust.

do both? why not. if you got the time. although i say if you have a 2.5in exhaust i wouldnt bother with a 3 inch test pipe. but if you make some test pipes and sell them for like 20 bux people will buy them. jes my .02


"Proud to be, a 2gnt" (was)


-mitsuman
95 gs
Hrc stg 2(not for long)
NER customer

Yeah that would good but I only have the flanges from my cat, and I have no idea where to get universal flanges.

You could get flanges and pipes from RoadRace Engineering. If you don't plan to run very high boost, 2.5" downpipe back should be very efficient. If you do plan to run more than 15 PSI (after your bottom-end build, of course), then a 3" cat-back will allow the turbo to spool up a little quicker, especially in the mid to high RPM's range.

The testpipe made a HUGE difference for me. Cooler EGT's, quicker spool up, more power at full boost, etc.............and it stinks!!!!