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Old 09-19-2006, 05:28 PM   #8
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Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
Originally Posted by bmussatti
Jim, but this is only if you have non-drilled rotors right? What does the dealership do on the "S" model with the drilled rotors to make sure the pads bed in nicely?

On the drilled rotors (referred to in Porsche Dealer Repair Manual as Perforated discs), Porsche says to measure the discs for minimum thickness in several distinct areas and also to look for uneven wear and cracking between the perforations. If any of the measurements are outside the tolerance given, the disc must be replaced, they cannot be machined or repaired.

On drilled rotors, bedding in is easier because of the perforations, but Porsche still cautions avoiding extreme braking at high speed, except in emergencies, for at least 200km.

So really, on the whole, the drilled rotors are a bad deal. Cost more, increase pad wear, have limited use (Porsche claims they have 1200 High Speed stops in them before cracking is so severe (more than 5mm) as to warrant replacement). Sounds like a lot, but really accounts for roughly 3% of the braking in the life of a single set of pads.

Empirically, they are more efficient. But, in practice, for Street Driving (heavily tracked cars excepted), they're really just expensive, unnecessary, overkill.

Of course, all this means nothing if you simply like the look of them or want bragging rights, all except the part about the added expense that is...

Happy Motoring!... Jim'99
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