The setup will start with a 2.5" downpipe but go to 3" exhaust including hi-flow cat (3" in & out) and magnaflow race series muffler (3.5" in and out).

I want to upgrade to a 3" downpipe, but it looks like i just won't be able to afford it right now. Drag wants like 250 plus shipping for a 3" dp and no place in town can custom make one for me where i live.

How much will the 2.5" dp really hold me back because i'm shooting for over 300whp on an LS-T?

 

you can make 300 on a LS turbo, with a 2.5 inch downpipe. just might need to turn the boost up a little more.

i had a 2.25 inch and went to a 3 and gained about 25-30whp..

 

I made over 400whp with an open 2.5" drag downpipe...so there's no need to buy a 3" downpipe if all you want is 300whp

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PureTeg420 &raquo;</TD></TR><TR><TD CLASS="quote">I made over 400whp with an open 2.5" drag downpipe...so there's no need to buy a 3" downpipe if all you want is 300whp</TD></TR></TABLE>

that sounds good

 

I made 402whp at 18-20psi on a 2.5" dp through a 3" exhuast with no cat.

 

i have a 2.5in dp with a greddy evo2 exhaust 2.25 and a e-cutout at the downpipe(b16a2 turbo).
with the cutout closed running the exhaust i made 245 but with the cutout opened i gained like 11whp and lots of midrange torque. No cat btw

 

351whp with a 2.5" DP and 3" exhaust at 13psi at 7500rpm. Although it is with vtec so, I guess I am not much help haha.

 

well over 400hp with 2.5in dp flaring to a 3in exhaust.
i've seen over 500hp with similar setups no problem