Limits of a 2.5" exhaust????

[Duk]

All right, after recently completing my twin-charger set up , and getting it all fitted into the car, I need to decide on whether I need a bigger exhaust or just work with what I’ve got.
I’m still using the same set up I had pre-adding the turbo. A scabby old 2.5” cat, 2.5” ‘Gonzo’ resonator and a 2.5” Genie straight through muffler. This system was just quiet enough to get left alone, but with the turbo now added, the whole thing is very subdued, the main noise when I give it stick is air sucking into through the pod filter.
Exhaust guy (top bloke he is) suggests keeping it 2.5”, ditching the Gonzo resonator, and probably a better cat.
Dump pipe is/had to be 2.5”, but is it worth while building a 3” system, or is a 2.5” system gunna cut the mustard
It feels like something is deffinately holding back its true potential.

[abently]

The dump pipe is where its at. Definitely get a 3" or even 3.5" if there's enough ground clearance. Put a 3" cheap High-Flow cat closer to the muffler and just keep the 2.5" muffler. Ditch the old cat and resonator ofcourse.

Sounds like you need a bigger exhaust Housing on that Turbo though. Set-up a back-pressure gauge if you can be bothered and check it on a dyno ?

[madmont]

2.5'' should be good for about 190KW without any losses from backpressure.

[The Real Roadrunner]

power figure being aimed for? the actual 2.5" pipework wont be the restrictive parts, the cat muffler and resonator will be and in that order so just fit the highest flowing units you can and it should be fine.

2.5" dump pipe ive seen 280rwkw so i cant see much of a problem (not ideal but hey it worked)

cheers
linden

[01jzcressy]

If it is a decent mandrel exhaust i dont see why you would have to go any better.