500hp+ Exhaust question

[2003kingranch]

As in my sig i have a 4" MBRP with a 3.5" down pipe. very shortly (next mon (30th) my truck will break the 500hp+ mark. 190/75's and a 68mm RCD. while the truck is apart and motor out, i was thinking of buying a 5" exhaust with a 4" down pipe. or is bigger exhaust unnecessary. there's all kinds of crazy numbers people throw around and claim like with the stock intake will take 500 hp, 4' exhaust is good under 500hp ect.. i dont want to get the truck together and find out the exhaust is borderline to small.

[Dave At BD Power]

In my experience a 5" exhaust can be a want not a need, I have been around diesel trucks on dynos for 15 years and do not see a any benifits to 5" exhaust unless you want it louder. I find the 5" drones too much and have seen 800HP work great with 4" exhaust.

my 2 cents

Dave

[2003kingranch]

im not to worried about the sound. i was thinking egt's. but if 4" is fine thats $500 i dont have to spend

[R0tten]

you might want to get just the 4inch downpipe, i dont think you need it but it might help with egt's

[windrunner408]

yea if anything, just get the 4in down pipe but a 5in is NOT required at all. not saying i dont like mine because I do but it is definitely not required.

[2003kingranch]

i might just get 4" down pipe then. i want to do a single stack. but my trucks way too nice to cut a hole in the bed

[shu873]

Honestly I think you'll be just fine with what you have. Go with a 4" DP if you want, but I don't think it will be necessary with a drop in turbo, even a 68mm Pmax. 4" DP's are a pain in the butt.

[2003kingranch]

4" downpipe will be easy with the motor out 3.5" downpipe isn't very big. someone dynoed 580 with190's and a 68. I'm on the fence on what I should do.


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[snopro_03]

I would put that money into the trans fund.

[pizza pig]

Originally Posted by 2003kingranch

4" downpipe will be easy with the motor out 3.5" downpipe isn't very big. someone dynoed 580 with190's and a 68. I'm on the fence on what I should do.


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Not really, being the 4" pipe doesnt really clear the firewall on 03-04 trucks... It always gets wedged between the cabs when they come down and rattles unless you beat the firewall. The turbo needs an equal diameter down pipe to match the turbine outlet, the stock turbo and all the upgraded VGT's are 3.5" outlet, so the 3.5" down pipe is sufficient