what will having a larger diameter downpipe increase horsepower or will it just make it louder thanks again

If you increase it on a mildly modified car, then it won't give you too big of gains, nothing really all that noticable.

Depends on your engine. With naturally aspirated engines you'll want some back pressure. A huge exhaust basically eliminates this and you'll get lower acceleration, but a lil more top end. If u have turbo, bigger is better; to a point. Turbo relies on exhaust to power the compressor, the more exhaust going through your system, the more you'll be able to boost.

This post has been edited by Supersprynt: Apr 5, 2004 - 9:21 AM

ok thanks guys

some of you that are turboed and have upgraded downpipes, what size did you go.

3 inches (aussie dp)

that seems to be the standard. do you know how much that added for you. I heard they make a huge difference on turbo applications.

I like the numbers in ur sig uzthedentist. have you ran the 1/4? would like to know the 60' time u get out of it too.

This post has been edited by UT_Celica_GT: Apr 5, 2004 - 7:30 PM

Stock DP on the Alltrac (ST185) is 2.25''. Mines stock right now cuz they are pretty expensive. The Aussie seems pretty popular but its close to $300.