You want them so they curve away from the direction of rotation, as it is a centrifugal pump. Turning them in the other direction would still cause the air to go from the center to the outside, however it is much less efficient at pumping the air when the vanes are pointing in the wrong direction. Wilwood rotors should come marked left and right.I have a question about the directionality of the rotors. When looking at the rotor, which way should the vents face? Looking at your pics, it looks like yours point towards the rear of the car (when turning in the forward direction, air would be pulled in from the center of the rotor and blown out from the cooling fins/vents at the outer edge of the rotor), or should they face forward (so when turning in the forward direction air is pulled from the outer edge of the rotor towards the center of the rotor)?????