RS America came in for some track damage. The owner had some brake issues. I can't imagine why I've seen this many times before, but never this bad. EVERY hole has split

Sort of reminds me of the many articles by engineers telling you not to drill through rotors. Or buy them drilled. That is one messed up disc.

Yes, this is pretty typical for a tracked car.

The PCA rules for inspecting rotors state that no cracks can extend to the outside edge.
I seem to remember it stating that a crack can't extend to another hole either, but can't find that now.

Agreed on the drilling part, which is why I pay extra ($20) for the Porsche OEM rotors on my 993 as they cast the holes into the rotor as opposed to Zimmerman who drills them.

These cracks are pretty serious, I'd probably replace this disk.

Probably stress cracks from using a drill that is not sharp enough and drilling too fast in either drill speed and or feed. I would also use coolant when doing this operation.

That rotor got very very hot.

Aside from the cracks, That rotor is wore out regardless....

I doubt that drilled rotors are the issue. Yes, that happens but this guy needs to pay attention to his brakes. Like Eric and Jeff said, those rotors are worn out. I don't think it happened in one track event either. If you're going to track your car, you need to (as Scotty said) check your rotors and pads frequently. Bleed your brakes pretty much between every event. While autocrossing is hard on tires and pretty much not hard on anything else, track events really work the brakes (and the tires but less so...)

nothing beats mass and air flow!