I'm just looking for some educated guesses on what power levels different size setups can support (this is a turbo application, not sure that it matters with regard to flowrate) without becoming TOO much of a restriction. This would be at the most restrictive part.

My inital guesses -
Single:
3" - 500hp
3.5" - 750hp
4" - 1000hp

Duals:
2.5" - 700hp
3" - 900hp
3.5" - 1200hp ?

I'm basing this on cross sectional area, taking into account that two pipes at the same area will have more friction due to surface drag, and also what i've seen other cars make with a certain exhaust setup. I'm sure its more complicated than i'm making it. Just throw some numbers out there.

 

Here is a pipe diameter chart from Dynomax/Walker. Magnaflow and Flowmaster have similiar charts. I have posted this a couple of times but it needs to be shown again from time to time.

 

so 400 hp on a 350 = ? lol

 

I hope to be at the 400HP mark on my 350 in a couple of months. Hehehehehe. Just a couple of more mods and with TPI no less. Also looking to be in the 12.5's come this Fall/Winter and the cooler weather.

 

Wups i messed up my bad,

i meant to say

450 hp on a 350 would = what size pipe. Probably going with a single . 3.5?

 

At 450HP the chart says either a 3" dual pipe or you should consider a 4" single pipe for optimum performance.

 

i hope thats a pretty conservative chart. I'm planning on single 4" split off to dual 3" and straight through mufflers. I need that to be good to 600-650ish. hmmm . . . .

 

but mines a 5.7 wheres is say in there

350 5.7l 450 hp lol

 

a 450 hp 350 I would probably run 2.5" - 2.75" duals on. 3" duals are way overkill, 2.75s are a little big.

For a great discussion on this, click the link:

http://www.fbody.com/cgi-bin/anythin...i?msgid=766773

VERY informative - even includes neat drawings!

 

fyi, i run 450horse on a 1 3/4 lt headers to 3" dual to a y, which is 3" back...

 

The above chart is just a guide line.