Any one here running beveled rotor? I just came across this seemingly good mod to the rotors themselves. I can't believe this is the first time I have heard about this.




Top image is a stock rotor vs beveled rotor on the bottom.

 

I'd think the biggest reason for housing porting over a rotor bevel is simplicity. Rotors would have to be rebalanced after cutting away material. I've seen it done in high cost builds, but the average home builder has a tighter budget.

 

similar to scalloped rotors

 

As was said, the biggest reason is cost and simplicity. Without a decent mill it's hard to do each face the same. If you are going to do this, then you might as well lighten the rotor at the same time, since both modifications require balancing.

 

Per your title, a beveled rotor will have an effect only on the opening and closing time of the port, while, more importantly, the goal of porting the housings is to increase the airflow through the port whether or not the actual timing is changed. Beveling the rotor is part of eaking out that last 2-3% hp gain as opposed to the first 95%'