My set up at the moment is:

Wiseco 8.8:1 Forged Pistons
CAT Power Super H Beam Forged Rods
Turbonetics T3/T4 Turbo V trim stage 2 .48 51 Lbs/min
Turbonetics Evolution wastegate
Turbonetics Raptor BOV
440cc Lucas Injctors
P28 mapped w Crome
2.5" Downpipe
2.25" Cat back with Sports Cat.

I'm going to be changing the exhaust to a decatted 3in custom mandrel bent system and was wondering if it was worth changing the downpipe to a 3" or just stick with the 2.5"?

I know it will spool quicker with a 3" but how much quicker are we talking?

 

definatley worth the full 3 inch from the downpipe back...

 

my buddie has a ls with a t3 t04 57, 63ar switched from a 2.5 to a 3 open and it spools about 200rpms sooner but he also switched from a log to an inline pro at the same time, but if your going to run a 3" system then i'd switch it out so it's 3" all the way back

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by quik sol &raquo;</TD></TR><TR><TD CLASS="quote">definatley worth the full 3 inch from the downpipe back...</TD></TR></TABLE>

x2 free up the power.

 

So keep the 2.5" downpipe and have 3" back from there?

 

no. put a 3" downpipe and full exhaust, is what everyone said and myself as well.

 

Damn language barrier.

You say downpipe back when we say from the turbo back.

Full 3" it is then.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by quik sol &raquo;</TD></TR><TR><TD CLASS="quote">definatley worth the full 3 inch from the downpipe back...</TD></TR></TABLE>

Couldn't have said it better. Take it 3" all the way back, because if you want to up the boost in the future, you won't have to spend more to get another DP made. Planning ahead ftw