Carl:

Any way you know of to avoid frt rotor warpage during track use?

Yes, kind of like I know how to avoid getting speeding tickets. Sometimes it works, sometimes it doesn't. Unfortunately, I have failed at both (avoiding tickets and warped rotors) far too many times, but here are a few hints:

1. break in your rotors for 500 miles before tracking. This is *very* important. Tempering the rotors is something that has sort of been forgotten lately, but was brought back to me recently as I was ordering my 5th set of rotors for this year. My "son" Todd drives to and from the track, and has been getting a lot more out of his rotors than I have (he drives the 800 miles, whereas I trailer). I think that there is a connection. I have heard of some racers putting their rotors in the oven for tempering, but I have not yet tried that. I will, however, and think that 150 degs for 1 hour, than 200 for 15 minutes might be just right. Caveat: this is my Mr. Hyde side talking. Try at your own risk!
2. If using race pads (recommended, I use PF 90's), use them ON THE FREEWAY (not town; they will gouge your rotors until they are warmed up) for a hundred or more miles before tracking. It will coat your rotors with pad material which will keep them smooth and free of shutter.

2a) In lieu of this, keep an extra set of rotors, designated solely for use with your race pads. I try to have a set of rotors for each set of specific pads (street, autocross, track).

3) rotors: stock is fine, floaters help only a little, in my experience. Stock knock-offs from Brembo cost about $120/set of fronts (BMP and others), whereas OE BMW rotors cost $250 to $300. Floaters cost even more. I use up rotors like gas and oil, now that they are so cheap. I wouldn't go too crazy over a set of warped rotors. At $300/set, I was much more worried about longevity.

4) brake lines and fluid: not necessarily related to rotor warpage, but I do recommend using stainless brake lines, and a good racing brake fluid. I use ATE Super Blue.

5) ducting: try the Donahue brake ducting method that I list below.

6) warm up your rotors, pads, fluids and yourself SLOWLY. Brake gently, "squeeze" on the pedal, squeeze off. *Work up* to throwing the anchor overboard. There is a place for all-at-once braking, but even then, do it smoooothly.

7) let every second or third lap be a cool-off; you don't have to go 10/10's every lap. Moreover, there is always a chance to cool things off; you get behind a slow car, and know that you can't pass him for 2 or 3 turns. Back off a little, slow down, let things mellow, and wait until your passing zone comes. Then get back on his bumper
to let him know you are there, and resume your quest for the next guy down the track.

and finally.......8) read 3 again. Worrying too much about making one set of rotors last the whole year is counterproductive. Hard
working rotors warp, period. I think that these hints will help prolong their life, however.

Regards,
Carl Buckland

Here is the Donahue brake ducting method, with some extra notes from me:

BRAKE DUCTING

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx remove the ducts. Tape over the opening into the wheel well. Cut away the lower inside wheel well shroud near were this hole is. Use
34" (3' is slightly too long) of 2 1/2" duct hose (again from Pegasus; I use the medium expensive stuff, something like $7-9/ft).
3" is too large (3" worked beautifully on the 2002, but there's more room in the wheel wells). Connect the hose to the cutback duct (it sort of threads right into the rear part of the duct), through the hole you've cut (I squeeze it into an oval shape at this point) and use a tie strap to tie it to the drag strut. The important point, and the hard part, is to lead it so that it clears the wheel at full lock-it is possible, but takes a little bit of effort. For the final
connection, it's best to remove the wheel, and rotor. Cut away the inner part of the brake shield (I used several radial slots, and rolled the metal back) so that the ducting will fit in (make it a tight fit), and put a hose clamp around the cutaway parts of the shield to help hold the ducting in. Another hose clamp around the strut and ducting might help. If you get the ducting a couple of inches away from the inside of the rotor, this will give the best effect. I tested the performance and optimum fit by using a leaf blower into the duct at the front. I then fiddled with how and how far the ducting went into the lower strut/cutaway shield until the air coming out of the reinstalled rotor seemed to maximize.

After it's all together, it's good for most of a year in my case, before the ducting starts to wear out and has to be replaced. You can always keep it going longer with applications of duct tape. Clearly, it would be even better to use the fog lamp openings-they are larger and not needed anyway. I decided to go the route above because it was easier. It was easier to remove the factory ducts, and easier to adapt a duct into this opening. Furthermore, it would be harder leading the ducting from the fog lamp. In any case, I will probably try to do this sometime in the future. (Similarly, I'm looking at removing the left side headlight assembly to give improved cool air flow to the air cleaner.)

I hope that the above isn't too confusing (seeing my car would make it so much clearer); I'd be happy to answer any further questions.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx I followed up with.....

I have some trouble visualizing this:
" Tape over the opening into the wheel well. Cut away the lower inside wheel well shroud near were this hole is. "

It is because the new hole in the shroud is in a different place than the original hole where the duct exited. The new hole is larger, and more inboard than the original hole. Why do you remove the original duct?

It is because the 2 1/2" hose is larger than the duct.

You then say:
"Connect the hose to the cutback duct"

I thought that you *removed* the duct. Do you mean "the hole in the cut out shroud"?

YES

Then you say:
" and use a tie strap to tie it to the drag strut."

He means to the strut.

Finally, you suggest:
" Cut away the inner part of the brake shield (I used several radial slots, and
rolled the metal back) so that the ducting will fit in (make it a tight fit), and put a hose clamp around the cutaway parts of the
shield to help hold the ducting in. Another hose clamp around the strut and ducting might help. If you get the ducting a couple of inches away from the inside of the rotor, this will give the best effect."

For better cooling, I have already removed the brake shields. Are they necessary to holding in the duct hose? My guess is they are *integral* to the design, and are the only thing that CAN hold in the duct hose. If this is the case, the question becomes, "Is it better to add ducting, which ties into the shields, or is it better to remove the shields?"

Carl talking: Leave the brake shields on. They are not easy to remove, as they involve removing the wheel bearing, and they do help
to hold the ducting in place. Also, I think that the shields can be bent inward, which helps bring more air into the hub. If you don't or can't place some duct hoses, then I would recommend removing the shields. There is also the downside that they are there for a reason; to keep debris off and out of your brakes.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Carl again....
I bought all of the stuff that I needed from Racer Wholesale for about $104. Parts are: SPA-D109 air duct 13.95 SPA-D103A hose
adapter 3" to 21/2" 11.95 x 2 THE-SS250 11 ft (only size avail) of 2 1/2" silicone hose 49.28. Silicone is probably not necessary, but it could get hot at the hub Racer Wholesale: 1-770-998-7777

Good luck, and let us know how it worked out,

Carl

Parts are:
SPA-D109 air duct = 13.95
SPA-D103A hose adapter 3" to 2-1/2" 11.95 x 2 = $23.90 THE-SS250 11 ft (only size avail) of 2 1/2" silicone hose = 49.28