There are the types of rotor warpage. One type is what I call "cold warpage" and the other is "hot ghost warpage". Cold warpage is a permanent warpage which you will feel at all speeds and temperatures - it is typically the result of poor casting and quality control. "Hot ghost warpage" becomes evident only when the rotors reach a certain temperature, such as when they become hot after hard braking; it results from uneven heating and cooling during the heat tempering process and/or the final cryogenic treatment of the rotor. This type of warpage in the rotor is NOT evident when they are cold - you can literally put the rotor on a lathe with a feeler gauge at room temperature, and it will spin true...but heat it up to some arbitrary temperature, say, 500deg, and the warping becomes evident.
Now, there is a third cause of brake shudder, which is NOT caused by a warped rotor, but can often lead many to believe that their rotors are warped. This third cause is "friction material film transfer", which is essentially the irregular, non-uniform deposition/transfer of brake friction material onto the rotor surface. All high-performance compounds exhibit this phenomenon to a certain extent at various temperatures, with some compounds being very hard offenders, indeed. When the brake friction material is deposited or smeared onto the rotor surface in an irregular pattern, upon application of the brakes, the brake pad will "grab-and-release" on the film transfers due to chemical adhesion, resulting in a brake shudder, and thus simulating what is often assumed to be a warped rotor.
Andie Lin
[This message has been edited by HomeDepotNSX (edited 03 October 2001).]
) anyway, after 2-3 sessions, my brakes were shuddering like hell. I have stock everything. My questions are...
