Whta would you guys recommend exhaust-wise for a 408 with about 15 psi? Something in the 800-900 hp range? Right now I have the Corsa, 3" single. Trying to figure out what I'll need to go with when turbo time comes.

 

I'd say 3 1/2 " if not 4" that things gonna move some air LOL... I'm assuming you are going to stay with a Y setup?

 

If you haven't heard, bigger is better for turbos.

IMO, a 5 inch duramax setup would work great.

 

Are you wanting single or dual exhaust? I am thinking dual 3" would be sufficient while keeping enough backpressure for low-end.

Edit:hmm I actually do not know too much about your motors and just thought that they actually use a y-pipe. I guess 4-5"

 

It's gonna be a single front mount turbo, so it'll be a single pipe from turbo back.

 

You will be fine with four inch. Thats what i have on mine...with a 30" Magnaflow diesel muffler. I'll get a sound clip when it gets going again.

 

single 4" piping will do the job with bigger tip. like 5inches!

 

5" would be a bitch to fit. 4" is prety tight too.

i had a 4" down pipe with a 4" cut out and from there back 3.5". i had 2 small bullets inline with a dump infront of the rear tire and it was very quiet.

with that set up there was a significant gain in hp with the cut out open. at 15psi i bet 50+rwhp running it thru the exhaust.

 

You can get a Dmax 4" turbo back kit from warpspeedperformance for under $300. I cut just one kit up and made a 4" for my cummins and I made 4.8T a 4" catback with what was left. There is a ton of pipe and bends in those kits.