I've grown rather curious about some things with exaust flow and was hoping someone would have some insight. If a vehicle has a 2.5" cat converter and midpipe coming from a turbo setup (small mitsu turbo with exaust side of only 2" inlet diameter) would getting a 3" full exaust, with cat, really make any difference than a 2.5" I already have (i have a high-flow cat already)? Exaust gases exiting the turbo will cool down as it moves down the pipe and through the cat causing the air to condense. In theory, a 3" exaust just seems overkill for the small turbo, but I've never done any hp or cfm flow tests so I just don't know. If anyone has any insight please help me understand.

 

Stock mitsubishi turbo off a 1g or 2g? Either way, 2.5 will be fine... you won't see any gains going any bigger, no matter what PSI your pushing out of it. At least not enough gains to warrant spending hundreds on a new exhaust.

 

Here's a very technical Intake & Exhaust flow I found on the net awhile ago, and stickied over at HP:

http://www.hyundaiperformance.com/fo...ic.php?t=21285

 

its the alpine turbo...it uses the mitsubishi turbo (like a garrett turbo, turbonetics turbo, etc.). From what i've learned mitsu makes their own turbos along with a bunch of other stuff. Its the same turbo as the 1g but with a diff compressor wheel--its suppost to give some better numbers.

 

Ye, I ran 2.5in exhaust for a loong time on my Eclipse GSX... I think I saw about a 8whp gain at the upper RPMS @ 18PSI on the stock turbo when I switched to 3inch. This was on a 2g turbo however, but they really aren't that different.

But you probably won't have to worry about that, I don't think you'll knock it up to the boost pressures I did.