i'm looking at doing a turbo set up on a 2.8L would it be good to have a 3" dual exhaust or more like dual 2.75"

 

With a weak 2.8 and turbo you arent going to flow enough air to even need a stock single 2.75

 

From what I've heard, you can't go too big after the turbo. So keep in mind that you probably won't need more than 3", but don't go too small. I'd also definately stick with single exhaust as you are going to have a single turbo, and that just keeps things from being unnecessarily complicated.

 

oops i ment twim turbo useing too eclips turbos and inter coolers (also 2 of them) so then what 2.5"?

 

Just FYI, a stock 2.8 will not take a whole lot of boost before she blows. If you do manage to pull off a TT setup, dual 2.5's would be more than adequate.

 

I've seen a 3.8 turbo buick swap running through a stock 2.75" running low 11's/high 10's all day. I'm sure that a single 3 or even a stock 2.75" will work fine for you

 

darn then how much boost could it take before i see a connecting rod on the freeway?

 

the 3.1 turbo in the Grand Prix ran (IIRC) 5-7 PSI, people have gone up to 10-12 on stock internals. not that it's a good idea...

building a V6 to take boost is quite simple, check out this link..

http://domesticcrew.com/660board/viewtopic.php?t=20


he's running about 250-260 crank HP, i think he's in the high 13's with it. keep in mind that it IS a daily driver as well.


and yes, that is a FWD gen 3 top end on a RWD gen 2 block, i think he's even using the MPFI / computer setup from a 2nd gen V6 Z24.

 

Just so you know, the 3.1 in the turbo grand prix had very little in common with the n/a 3.1. The turbo motor was built by mclaren (yes, that mclaren) for GM.

And that dude in your link has WAAAAY to much time on his hands. That's pretty cool though.

 

on the contrary, the 3.1 turbo has slightly lower compression than a stock FWD Gen 2 3.1, other than that, it's got the same exact pistons, stock rods, etc. there is essentially nothing special except for the pretty plenum and lower compression and (rumor) a slightly different cam grind (and turbo of course)

*edit, that's the FWD aluminium head 3.1's i'm comparing to, not the RWD Iron head version*

a member of V6Z24.com contacted Mclearan and discussed the specifics about the engine with them. they did not use forged pistons because of the low boost involved. Several of us V6 guys have swapped those engines into 2nd gen Z24's.

they are one great engine, a buddy down in Texas took his a little further and is on track for high 11's this year: www.turboz24.com

he's got some stuff in there on the TGP engine as well..