ok so i currently have a 2.5" test pipe and i will be boosting soon and i am getting t3/t4 turbo and wondering can i keep my test pipe and do a 2.5 inch catback? or do i have to do a 3' catback for turbo. also piping for the turbo could it be 2.5 inch with a 3 inch downpipe and the setup i just asked about?????

 

you can do whatever size exhaust you want, 3" will allow for higher power output due to the lower back pressure, but in all honesty 2.5" is completely sufficient for a daily driven street car with respectable power. so ultimately its up to you

 

whatever you do, don't cause any bottlenecks. Meaning don't get a 3" piping to a 2.5" piping to whatever is left.

 

very good point

 

so it would be ok to do 2.5 inch down pipe all down through catback

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fullthrottleking &raquo;</TD></TR><TR><TD CLASS="quote">so it would be ok to do 2.5 inch down pipe all down through catback</TD></TR></TABLE>

Yessir. But it's been proven that you'll gain a bit more than 20whp if you change out to a 3" piping.

 

wow thats alot of lost horsepower if i do 2.5 inch ill just wait and have to buy another test pipe

 

is this going to be a daily driver? if so. 3" crush bent or 2.5" mandrel bent is fine. 2.5" crush is still fine but going the extra 1/2" will gain more freeflow and in turn, more hp.

 

I wouldnt go crush bent if I were you, if youre gonna go 3" do it right the first time. To me crush bent is a cheap and quick alternative that doesnt really cut it for me. Like I said do it right the first time.

 

X2. Go with 3", pay for it once and get the most out of it.