Directional vanes (which are often curved, but it is really the directional part that matters) are supposed to pump air OUT of the center of the rotor, rather than scoop it in. And since slots on those rotors are typically cut in the opposite direction, they look like the pic that was posted here when mounted on the car.



However, the rotors in the picture almost certainly do not have directional vanes, so it probably doesn't matter which way they are mounted. But I would keep them like they are in the picture since that is the normal orientation for slots. Someone posted a thread about this on the "other" forum, and there was some other reason given (besides the vane direction) for the direction of the slots, but the recommendation was the same -- make them look like the picture in this thread.



-Max

 

Yep, that's the one. Centrifugal effect if you care to think of it that way.