I have slotted and xdrilled rotors on the front of my FD. Which direction should the slots/hole rotate--center to the right or center to the left? I've seen them done differently on different cars and I don't remember how they were done on the race cars, but I think they go center to the right as if it was centrifical force driving them out.

Thanks! TP

 

If you are going from the hub, outward toward the tire, the should slant left-to-right.

 

That's what I thought. Thanks! I've read a lot about brake ducting, but I haven't really got any conclusions. Since my car is mostly a street car and the only ducting probably low/through the nose, I would be afraid of water and dirt getting into the rotor. Hot rotors + water would not be good.

 

The way you guys are describing it, the direction of the slots would have to change from the left side to the right side of the car. I'm not sure it makes a big difference though.

 

Slotted rotors are indeed dedicated to either the left or right side of the car. The 2 sets of Powerslots I've had were stamped 'L' or 'R' to help the decisionmaking process for those who are able to tell left from right.

 

Actually, it's the 'vane' of the rotor (not the slots on the outside) that determines which side goes on which side, *if it is a directional vane*.

http://www.apracing.com/car/brakedis...tification.htm

The slots (on the exterior of the disk) is to relieve the gas buildup that can occur between the rotor and the pad, along with 'cleaning' of the brake pads - and it's orientation is likely less important then which direction the vane is spinning.

 

I guess I learn something new! Thanks. The vanes were not directional. Would the same concept apply to crossdrilled rotors since they would go through these vanes?

 

Yep, yep, yep!

 

well I'm having conflicting data now as to which direction my Brembo's should go that I got from Ebay, I'll have to double check for an indicator... here's a bit I did find tho.

Which direction should the discs rotate?
It is a popular misconception that the slots or drillings in a disc determine the
direction of rotation. In truth, for an internally vented disc, the geometry of the
vanes dictates the direction of rotation. There are three vane types in use:

Straight
Pillar vane (comprised of many small posts)
Curved vane

The first two vane types are non-directional, and can be used on either side of the vehicle. The curved vane disc, however, is directional. A curved vane disc must be installed with the vanes running back from the inside to outside diameters in the direction of rotation. Please see figure. Orienting the disc in the manner creates a centrifugal pump. The rotation of the disc causes air to be pumped from the center of the disc, through the vanes, and out through the outside diameter of the disc. This greatly enhances the disc's ability to dissipate heat.

Additionally, all of Brembo's slotted discs are directional as well, regardless of the
vane geometry. The discs should be installed such that the end of the slot nearest
the outer edge of the disc contacts the pad first.