I plan on taking the hot rod to some Drivers Edge events once a little more chassis work is done. Since I'm building the brake system this week, my little mind wandered over to the SLR we've got in the shop.
I took a little peek to see how McLaren did the brake cooling. It's pretty impressive.
What surprised me was the effort put into cooling the pads and caliper. I've seen lots of systems that put air on the rotor but never one concentrating this hard on the pads.



You can see that McLaren had serious concern about the heat generated due to the shielding on the brake hose and wires.



They did duct a little bit of air into the center of the rotor (small ducting) but it's only a fraction of the size of that duct heading towards the caliper. Notice the heat shielding this time on the tie rod. They also shielded with lower ball joint with a closed knuckle.





Is it common for the hard core racers to put this much concern into cooling the caliper and pads? Do you think it stems from the rotor and pad material? I don't remember the Champ cars and American LeMans cars having that kind of setup.
The rears have similar duct work but it's not nearly as heavy. The air is drawn from scoops in the under body paneling near the differential cooler.

I recall the problems that Ford originally had with the GT40 in the 60s. They were killing rotors at an alarming pace. It turns out that the cooling air was too cold. They diverted hot air from behind the radiator across the brakes and that solved the problems with rotor failure.
One of my friends with a street/track Supra had a problem with too little caliper/rotor clearance on his Supra during the One Lap of America. The rotors grew with the heat and rubbed the caliper. That caused more friction and ended up boiling his brake fluid at the end of a long straight. That very nearly became ugly. Once the brakes cooled down, the rotors shrank a bit and the problem was resolved. They self-clearance and he had no further problems through the remainder of the One Lap.

What do you see on the track day cars you run with? I recall you mentioning brake cooling in a recent post. That made me think of the '99 - '02 CLK55 rotors for our cars and ended up with me under the SLR thinking about my hot rod.