Two days before, new cad plated rotors:



After first session, cadmium all gone. Here it is on the inside of the wheel:



After the third session with a full lap to cool down without touching the brake pedal:





Tooooooo much heat, inadequate dissipation and thus inadequate air flow to do the job.
This was with R4 pads, MPSC tires and 360 hp. Without the ducting I would not have tried the agressive R4 pads. I thought it was bulletproof but found out different.

On a side note to those who spend hundreds powder coating their calipers, the PlastiCoat $5.95 paint is still going strong.

 

So is the ducting pointless??? It seems as so.

 

Proper ducting will do good.

If I were to go after it again, I would build a larger tapered duct face, larger and smoother ducting and a larger ducting nozzle in the dust shield. The tubing would be 3 inch. That ducting is so tortuous I'm sure it was flowing minimal.

The clam shell approach to the rotors would be ideal.

 

You don't think it was just the drilled rotors that are the issue?

 

They didn't help.

 

Drilled rotors have more exposed surfice aria to the air. they should have stayed cool enough even with out the ducting woudent one think. The car dont have ducting stock and many people track the car any way and dont have issues..... I had brembo drilled rotors on mine and no issues.....

 

I'm sure it was a complete coincidence that the crack runs directly through the center of one of the holes.



So yeah, don't run cross drilled rotors on the track in this car unless you get your jollies from constantly buying new rotors.

 

Sideways,

What brand of rotors are those?

It seems the rotors shouldn't have cracked under any circumstances anyway, regardless of the cooling. Brakes can get literally red hot, and shouldn't crack. Were these machined rotors or cast?

Anyone else have any advice on cross drilled rotors?

 

actually you just bought cheesy drilled rotors, they cracked at the drill spot, this is why people run blanks when racing. slotted, drilled, cross slotted, hyper drilled rotors are just a silly trend.

and please don't link a f1 car with drilled rotors thats a whole different ball park.

 

He does not seem to get the point.