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Old 05-12-2005, 02:02 PM
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bren bren is offline
///Mpty pockets
Location: MD
 
Join Date: Jul 2002
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Quote:
Originally Posted by spta97
Here's a quote that explains it better:

"The drilled rotor so common on the Porsche 930 turbo is NOT really drilled at all. It is a CAST hole. Porsche did this to help minimize the effects a hole has in creating a stress riser in the surface of the brake rotor. A drilled hole goes directly through and interrupts the grain structure of the metal. Where as a cast hole has the grain structure formed around it in an uninterrupted flow. All holes in a brake rotor will eventually show signs of stress cracking. A drilled hole will crack much sooner than a cast one"
You said forged...not cast. Those are vastly different processes.

Quote:
From the Competition package PDF

"The cross-drilled, compound front rotors have been increased to 13.6" (up from 12.8"). "

I do not see any mention of the rear rotors being cross-drilled as well - is BMW incorrect?
No, what you didn't see mention of was an increase in rotor size for the rear. Where does it say the rears are not drilled?


Quote:
Again, reading the Competition package PDF:

"The M3ís already powerful brakes have been improved to meet the demands of repetitive hard braking experienced on the track."
Go ahead and track the ZCP and try to get the rotors replaced under warranty. BMW clearly states that any track time will void your warranty. Next time you watch an auto race check to see how many cars actually still use drilled rotors. They will crack when used on the track as is clearly stated in your quote above "All holes in a brake rotor will eventually show signs of stress cracking. A drilled hole will crack much sooner than a cast one"

Last edited by bren; 05-12-2005 at 02:08 PM.
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