2.5" or 3.0" exhaust piping on TT car? - Honda Forum / Acura Forum

NyQuiL · 06-05-2002, 02:32 PM

Ok ive been considering to get a exhaust system for a real long time now, just got a few questions. Ive heard to go with 3 inch piping for turbo exhaust, but is there really a big difference from 2.5 to 3.0 in hp gains?, and a guy from another forum told me this

" 3.0" on a STG 1 TT is too big ... you'll loose gas velocity
which translates to a loss in power. 2.5" is supposed to be pretty ideal. If you search, you'll find a couple guys who have actually gone down to a 2.5" from 3.0" after experiencing a mild loss in power. The exception to this, of course, would be high power applications - 500+ hp I would guess (don't quote me on that). I think I remember someone saying that 2.5" was good for up to 700 HP. Maybe just a rumour though. You'll hear a lot of import guys talking about 3" and 3.5" exhausts and that's what all their aftermarket ones are, but remember that they only have 1 pipe ... multiply by two for the Z and that's a lot of cross sectional area. "

someone please help on clarifying what size would be best for me. I dont plan on making the car a 1000hp beast. (would be fun though)

GSteg · 06-05-2002, 03:33 PM

2.5" on a 700 hp engine would be suffocating it unless you have more than 2 pipes running from the engine. i'd opt for the 3" . you get better turbo response from it. 2.5" i would say would be for all-motor. thats why basic bolt on exaust are only 2.5 inches(some are 2.75"). GO 3".

vg30dett · 06-05-2002, 06:12 PM

Nyquil, Z's have TRUE DUAL EXAUST SYSTEM, you don't really NEED 3 inch piping unless you have bigger turbos. I believe HKS Hyper exaust system has 3 inch piping. If I were you, I would just go buy some Greddy SP's(Looks better IMO).

Pic of Hyper

Pic of Greddy Power Extreme

Pic of Sp's

GSteg · 06-05-2002, 06:48 PM

oops..i of course it's a honda forum so i automatically thought he was talking about his honda

my bad. 2.5" should be fine..

vg30dett · 06-05-2002, 07:08 PM

CanuckSol · 06-05-2002, 08:38 PM

I need to put an exhaust on my car. I have a DelSol Si (D16z6) and I am going to be running 7-8psi off a K03 turbo. Should I run 2.5 or 3' all the way back. The flange for the down pipe is 2.5" so I am planning to run that back and posibly split it into two 2" pipes after the resonator. I am doing this to avoid a muffler. Just going to have the 2 pipes coming straight out the back. Bad idea?

I would definately like advice on this.

dptkfil · 06-05-2002, 10:14 PM

Quote:

Originally posted by NyQuiL
Ok ive been considering to get a exhaust system for a real long time now, just got a few questions. Ive heard to go with 3 inch piping for turbo exhaust, but is there really a big difference from 2.5 to 3.0 in hp gains?, and a guy from another forum told me this

" 3.0" on a STG 1 TT is too big ... you'll loose gas velocity
which translates to a loss in power. 2.5" is supposed to be pretty ideal. If you search, you'll find a couple guys who have actually gone down to a 2.5" from 3.0" after experiencing a mild loss in power. The exception to this, of course, would be high power applications - 500+ hp I would guess (don't quote me on that). I think I remember someone saying that 2.5" was good for up to 700 HP. Maybe just a rumour though. You'll hear a lot of import guys talking about 3" and 3.5" exhausts and that's what all their aftermarket ones are, but remember that they only have 1 pipe ... multiply by two for the Z and that's a lot of cross sectional area. "

someone please help on clarifying what size would be best for me. I dont plan on making the car a 1000hp beast. (would be fun though)

You are sooooooo Lucky because you got a Z... I am so jealous.... You don't even need to built your engine to reach 700 hp... If you are looking for an exhaust system.. I will recommand 3".... My friend's shop just did a Twin turbo kit upgrade on this 93 Z... It was dyno at 700+hp..My friend took it at the track with the permission from the owner of course.. He got 10.X sec ...sorry I don't remember was it a high, or low 10s but with Street Tires... Your car has so much potient so don't limit yourself to 2.5" go with the 3"... Good Luck

vg30dett · 06-06-2002, 01:23 AM

Quote:

Originally posted by dptkfil

You are sooooooo Lucky because you got a Z... I am so jealous.... You don't even need to built your engine to reach 700 hp... If you are looking for an exhaust system.. I will recommand 3".... My friend's shop just did a Twin turbo kit upgrade on this 93 Z... It was dyno at 700+hp..My friend took it at the track with the permission from the owner of course.. He got 10.X sec ...sorry I don't remember was it a high, or low 10s but with Street Tires...

Not to doubt what you are saying, but what are his mods????

dptkfil · 06-06-2002, 02:03 AM

Sorry .. I don't know what are his mods.. All i know is that he had an upgrade turbo kit (the turbo kit is about 10000) with some kind of stane alone... Trust me man.. you can ask people at Sac, CA.. it was a black Z with Wingwest body kit and 18".. The shop who installed everything is call MIDNIGHT PERFORMANCE ask for Warren, he can tell you what the Black Z got inside.. cause he had installed everything in there.. I also remember that the Z got a skyline brake ... and it's stop hella fast... the phone number is 916-852-6887