still have some learning to do... 4" downpipe?

[adw_terror]

hey guys, well im still learning a lot about these motors and i have a few questions... soon i will be purchasing some piping to fabricate my turbo-back exhaust(4" downpipes, and 3" all the way back) and i figured id try to fab up an up pipe as well... my question is what would be a good size and what kind of benifits will i see from doing this... thanks
-Josh

[StatGSR]

i cant tell ya much about up pipe size, but i can tell ya that a 4 inch DP is pretty much unnessiary unless your using some huge turbo(s) and going for like 700 hp....

[Huffer]

4" is overkill on a 2.0 or 2.5 engine... 3" turboback results in some pretty good hp ATW. The research and proven results are all out there - not to mention you may have some interesting clearance issues with 4" pipe.

Your bends will have to be spot on, with the reduced radial clearance...

My suggestion - get some used, proven parts from a WRX/STi in and have them fitted to suit...

Unless you like the custom route, which is cool too. Good luck!

[adw_terror]

yeah i guess ill just go for a 3"... i was thinking more along the lines of accomidating my eventual power goals, but a 3" wont hurt me too much... i guess i just liked the sound of a 4" downpipe :grin:
-Josh

[rougeben83]

I think the 3" would be plenty; especially when youre going to be bottlenecking the downpipes after they meet to 3" anyway.

I know a lot of 400bhp Scoobies running around with 3" TBE's so I think that the pipe diameter will be the least of your worries once you start going past the 300hp mark on your car.

[adw_terror]

the pipe diameter will be the least of your worries once you start going past the 300hp mark on your car.

already there :grin:
-Josh

[rougeben83]

the pipe diameter will be the least of your worries once you start going past the 300hp mark on your car.

already there :grin:
-Josh

Oh, you bastard :grin:

[backpack09]

I say go for it, if you can find a fab man to make it work. On a turbo car, you are never going to have too much flow. I know a couple of DSMers running FP3575 turbos with 3.5 and 4" exhausts on there 2 liter cars. They are be pushing 500-600whp.