hans14914

I remember reading that a rennlister once extrude-honed an s4 intake manifold, and there was no noticible performance gain. What is the stock intake runners ID, and has anyone enlarged the runners and the ports in the head? If so, was the gain worth the work? What size was the runner/port enlarged to? I am taking off my intake next week, and would like to optimize the system as much as possible. I have a port and polish kit lying around somewere.
Thanks

slate blue

I believe it is worth it only though if you engine has the cams and heads to exploit the extra flow. On a stock engine the manifold is not the bottle neck.

Cheers Greg

P.S I would like to see the flow figures for the throttle body.

hans14914

Do you know what the stock ID of the runners is?
Thanks
Hans