exhaust bore size

[PaulW91]

just wondering if anyone could help me I'm going to be getting a new stainless steel exhaust made for my car once I get it back on the road and it'll be running gsxr throttle bodies and phase three cams with four into one manifold and have been told to get a two inch system made to get the best out of it but the plans are to go boosted in the near future so would I beable to get a two and a half inch system made just now or would that have a negative effect on performance just now?
thanks for any help

[PaulW91]

nobody tell me anything?

[KamRacing]

if you go 2 1/2" you will certainly loose gas velocity in your n/a setup

[Jungle]

Besides, whats the piont in spending money doing a ITB set up if you plan on boost?

[burgerfeet]

The bore size of an exhaust in a normally aspirated engine is critical. Too small or too big will affect you performance ie loss. Forced air induction, eg turbo doesn't really matter.

[axsaxoman]

The bore size of an exhaust in a normally aspirated engine is critical. Too small or too big will affect you performance ie loss. Forced air induction, eg turbo doesn't really matter.

Hi,
I agree with most of what you are saying ,but with s/c it is same as an n/a car --ex size + primary lengths+ postion of first box do matter-
-turbo no --as big as you like -but too small could be a problem

[burgerfeet]

Hi,
I agree with most of what you are saying ,but with s/c it is same as an n/a car --ex size + primary lengths+ postion of first box do matter-
-turbo no --as big as you like -but too small could be a problem

I agree with that also. Didn't mention super charging as I didn't thing it would be a consideration. Then again blower was mentioned. Was just thinking is was a loosely coined phrase for turbo. If I recall, too big an exhaust with a super charger robs it of peak boost.

[burgerfeet]

I agree with that also. Didn't mention super charging as I didn't thing it would be a consideration. Then again blower was mentioned. Was just thinking is was a loosely coined phrase for turbo. If I recall, too big an exhaust with a super charger robs it of peak boost.

Nope, blower wasn't mentioned....boost was though so turboing I guess.

[PhillipM]

You can breathe pretty well through a 2" exhaust up to about 180 or so - it depends how much power you think you'd be running when your FI?
I imagine your thinking about a supercharger rather than a turbo give you'd have to alter the manifold and exhaust anyway for the latter.

[PaulW91]

thanks for the info everybody