Quote Originally Posted by ZeForce View Post
Actually, the intake piping should have 25% larger cross-sectional area than the throttle body, which is ~70mm for a stock VTiR throttle body
are u sure its cross-sectional area and not just diameter?

if u have a 70mm diameter t/b u need to have a diameter 25% bigger ?

a 25% bigger diameter would mean a 90mm pipe

or do u mean

u take a cross-section of the pipe then work out the area of the cross section (area of a circle), then work out 25% bigger ?

so the area of a 70mm diameter circle is 38.5cm2

so 25% bigger is 48cms2

an 80mm diameter pipe has a cross-sectional aream of 50cms2.

so if u do mean cross-sectional, whats the point u r only going 1cm bigger in diameter?

70mm is just shy of 3" so y not just go 3.5 or 4" pipe?

or is it like most other things, too much is bad, too little is bad. u have to get it spot on?