Size for Exhaust?

[VIKING RACING]

Will make a new Exhaust system, so the qustion is.
Are a 2.5" pipe size enough?
and does anyone know about a good place to buy ready made bends here in Auckland?
John

[jif]

Hi John

2.5" is meant to be fine up to ~300 rwhp, so unless you've gone upgrade crazy lately it should be plenty !

Incidentally I was talking to the guys at Al's mufflers and lightweight Ti (titanium) tubing is $80/m ... <nudge nudge>

-jeff

[Trevor]

Do not be conned into thinking that "big bore" is the way to go. Designing an exhaust system requires expertise. Do some reading, and not blurb from advertisers, or the magazines which tout for there advertising money.

Off hand I would say that a 2.5 inch pipe is too large, and will not allow you to achieve correct resonance.

[jif]

On 12/05/07, Trevor <horsepower@mx5forum.co.nz (horsepower@mx5forum.co.nz)> wrote:

Do not be conned into thinking that "big bore" is the way to go. Designing an exhaust system requires expertise. Do some reading, and not blurb from advertisers, or the magazines which tout for there advertising money.

Off hand I would say that a 2.5 inch pipe is too large, and will not allow you to achieve correct resonance.

unless there's a turbo bolted to the block ... ( ... is that still the case John? )

[Anthug]

Hi,

2.5" for 1.6 turbo and 3" for 1.8 turbo.

2" otherwise.

Stainless sounds nice.

anthony.

[Trevor]

Hi,

2.5" for 1.6 turbo and 3" for 1.8 turbo.

2" otherwise.

anthony.

A turbocharged engine, obviously does not have a tuned exhaust system. As there was no reference to a turbo I assumed a naturally aspirated engine was involved. In this event 2" should be fair enough.

Trevor. *<)

[SLYDIT]

yup stay with 2.5" pipe for the turbo. But make sure that the bends are MANDREL or pretty damn close to it...crappy press bends will loose you around 30% flow on a 90 degree bend and there are at least two of those on the car (in and out of the rear muffler) you may even want to ramp up to 3" past the diff for those bends and the rear muffler.

Im running a 2.5" mandrel system with a 18" cobie resonator and a rear muffler designed for rotaries! (boy racer at heart!) then to a 95mm chrome tip.