exhaust

[99deepgsx]

i have 1999 gsx and right now its stock t-25 need to know whats the best pipe diam 2.5 or 3? for downpipe and catback.......looking at the n1 right now.....

 

[Streetbeat]

really just depends on how far you want to go.
do you plan on upgrading your turbo?

 

[trig21turbo]

Originally posted by Streetbeat
really just depends on how far you want to go.
do you plan on upgrading your turbo?

I think you should get a 3" cat

 

[99deepgsx]

probably gonna upgrade in the future to fp big28 or evo 16g with supporting mods

 

[arffy]

Downpipe 3" for sure w/2.5" catback would be my recommendation for the street, unless you spend more time at the track... with the minimal more restiction of a quality 2.5" catback will keep your torque curve in the more user friendly street range and also graduating down from 3" to 2 1/2" acts somewhat like a venturi effect (not just my theory) and will speed up exhaust flow.

A member mentioned that if you are planning on getting the most horsepower that you can out of your DSM you might want to spend the money and go with a 3" mandrel bent cat-back system to begin with. This will help you to eliminate having to replace the system twice when you get so many mods on there that the normal low restriction system gets too restrictive.

If, however, you aren't looking to go past the 12.5 second mark than you could easily get away with only a 2.5" system. The price is considerably less than the 3" system and the noise levels are tamer. From what I've read on here the gains from the larger 3" exhaust are minimal (for the price) until you start doing things like getting new turbos, porting the head, and getting into boost levels which require race fuel. The money you save on the 2.5" cat-back can then be spent to buy the mods which will take advantage of your new breathing ability.