geoffucla

Okay, there's got to be some way to keep the rotors from cracking so quickly! I just installed a set of motorsport rotors, and after a DE weekend, I can already see the beginnings of cracks from the holes! I've got the cup front lip and the stock brake ducts. Has anyone tried installing any brake hoses or ducting to keep the rotors cool? I noticed Gert has a set--anyone tried it?

Thanks guys--

Geoff.

Sloth

I recently noticed what looks like dust shields or metal backing plates on back side of the rotors. I would think their removal would aid in keeping the rotors cool. Unfortunately, it looks like the rotor needs to be pulled to remove the shields.

Anybody know anything about this?

SPR

get the Motorsport CUP ducts they're deeper than the gt3 ones and funnel more air.

enthusiast

More air flow and other pads will help but these iron cross drilled ventilated brake disks normally crack out before they wear too thin. While the cross drilled holes help in many ways they hurt as they are weak points in the disk. I posted the following replacement criteria previously.

Guidance from Porsche AG on 964 Cup Car Cast Iron Disks.

"Ventilated discs will develop small heat cracks with race use. These cracks will have no effect on braking. Discs must be replace (sic) when three or more adjacent radial holes are connected by cracks or the outside edge of the disc is cracked."

I have been following these "crack" replacement criteria for years with no disc failures. The holes are weak points in the disk. The heat and stress cause the cracks. The air cooling fixes will help, but they won't eliminate the cracking. Also note that the inside of the disk has less cracks than the outside because the air flow enters there. The maximum cooling takes place while the vehicle is moving.

A brake disk is a consumable item, far more noticeable on a high performance sports car.