Quote:
|
Originally Posted by phoenix
No stratight answer, but Porsche have run drilled disc on competition cars for decades, which they would not do if there was no advantage. However Porsche also seem to be able to avoid cracks, which not many others can claim I believe.
|
I do believe a lot of the drilled, milled or cast in holes has to do with marketing and give what the customer wants, not really any benifit at all. Rotors with holes in where originally designed for outgassing of asphestous brake pads back in the late 50s and 1960s.. While asphestous is no longer used in brake pads, there is no longer a need for rotors with holes in.
Most manufactures state the air should flow into the center of the hub and out the veins. This is also were the brake duct hoses from the fenders should point too, the center of the hub to cool the hub and then the air is pulled out though the rotor too cool the rotor.
So when you look at a rotor from the side, the veins should curve back at 12:00 O'clock to pull the air OUT though the rotor, Not forward and pull the air down onto the hot hub and bearing.
Does it really make a difference which way the veins curve? for the most part, no.
I have lots and lots of photos of crached rotors, drilled, slotted and plain sided, only the rotors with holes in do crack faster.