Skip01

I know the potential gain with going 3in is huge, but anyone out there making good numbers on smaller?

Trying to get all my ducks in a row for a coming up project.

Not looking to be that loud , I know 3in on NA vs 3in on a turbo car is way different , but still might be a Lil loud for my taste.
I wonder if 300hp on 2.5in is as much or more strain than 400hp on 3in exhaust, as far as motor stress.

If you figure that same 2.5in setup with a 3in exhaust would make that much more power with a freed up exhaust.

What ya say?

Suggestions or comments?

Skip01

37 views and not 1 comment?

Bailhatch

If you can deal with an open wastegate you can really good power on 2.5". mid to upper 300s with little stress. but 3" is better

Skip01

Meh.....haha....i had open wastegate on my Talon.....i did not that sound at all.....that was my other change i wanted to do on this Honda...no wastegate dump

What ya think....3in and rerouted wastegate quieter than 2.5 and open wastegate?

92redhatch

I had an open 2.5 downpipe with the dumptube routed in the downpipe and I made 300whp at 12psi

1DayIllBFast

right now i have a 3"dp to high flow cat to 2.5" back exhaust and at only 4.5psi i made 246whp on bone stock gsr

DOHC_16v

I made 400whp on a 2.5" DP... open DP :D

jhammond_82

iTrader: (1)

one of the local tuner's here is pushing over 400 hp through 2.5" exhaust.

Flr Power

The best solution is to measure backpressure near the end of the downpipe. Look for no more than 5-6 psi backpressure. I have measured around 4 psi backpressure on an b18b pushing 280 whp with a 2.5 inch exhaust. It's a very quiet exhaust (with Magnaflow strait through muffler no cat).

I would say past 330 whp go for 3 inch. But this is a big debate since people have very different opinions on that.

HYREV2NR

I've heard of measuring backpressure before but never seen whats used. Clue me in please? Thanks.

roadsqueegy95

im glad i found this thread, been wondering the same thing myself! subscribed!

tek_civic

[QUOTE=Skip01;39656897.....i did not that sound at all.....[/QUOTE]

Then i totally on my last car. hahaa


Anyway i used to run a b16 turbo on 2.5 in, then later ls/vtec. The downpipe is much more important, the larger the better(to a degree). Then a free flowing 2.5 inch will make decent power and great sound. Although i never got as far as measuring psi etc.

Tjabo

I'm not sure I totally understand what all of this is, but it cracked me up! ! ! LOL!

Skip01

I does not either

Thanks for the comments....more would be appreciated.

I think the WS2 comes in 2.36 size....would it be worth it to get a custom setup for the extra .14 in?

xfrankx

i had a 3in custom made exhaust on my old car with a burns stainless muffler and it was quiet. the turbo quiets it down a good bit to the point where it sounded quieter than my friends stock gsr motor with an apexi n1. it just had a deep growl it was nice. so 3in isnt going to make it really much louder if thats what your worried about. just do 3in its not gonna be much more money and its worth it even if you dont upgrade to more hp down the road. i wont run anything smaller than 3in

Skip01

Ok....good call....ill prolly go with 3in, i figured itd be quieter being a turbo car

Bailhatch

I could never drive that engine with that exhaust. I have installed a bunch of those on Hondas and it's just far too loud for me, especially an older one with some miles on it. I guess that's why I have three mufflers on my 3" exhaust

Skip01

What ya think of 1 long resonator will do for sound and power loss?

3in dp, to long as i can fit resonator, to WS2 3in uni muffler

littleblue

I'm makin 396 whp on 2.5inch full exhaust. Open wastegate.. 3inch downpipe..

tek_civic

A Resonator on the streight section would be great, it adds a little size, but you should be able to fit it fine. They also dont take any power, maybe 2-3hp if you could really measure it, but when your in the 300range who cares, the sound will be great.