My experience with this is not to dissipate heat but to rid the Brake Pad of brake dust. Several years ago I wrenched some Road Course cars and I drilled the rotors at first with no problems but it was very time consuming.I laid an angled pattern and grooved the rotors with a ball rotary file.They were grooved so the rotation force slung out the brake dust. It worked great and took a lot less time. Paul
