[revetec]

This is a really cool process to port and polish....

Extrusion Honing


A good finish on an intake port is a slightly rough to feel finish that is not wavy. I have heard that bead blasting an intake port is the best because it creates small vortices that create a kind of an air ball bearing effect from the port to the intake charge. I'm trying to find more information on this.

One thing I can quote is the porting article on Wikipedia which states, "Flow bench testing shows that the difference between a mirror finished port and a rough textured port is typically less than 1%".

One thing that can be said is that when porting a head, it is easier to see the variations of port surface when polished. After you have completed a port and slight polish and inspect, a good practice would be then to rough up slightly the surface or bead blast the port. But then again it is stated as a 1% variation in performance between the two.