Had the pleasure of discussing crossdrilled vs. slotted with friend from Weissach recently...
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Had the pleasure of discussing crossdrilled vs. slotted with friend from Weissach recently...
According to Ing Elvis, Porsche uses crossdrilled rotors for a real world reason. I guess with pad compounds these days gas build up is not an issue. The real world issue that gets between the rotor and pad is steam. The steam is produced in wet weather instantly when rain hits the superheated brake parts. The steam is pressed into the holes on brake compression and give no compromise braking in wet and dry. He also said that the holes cool the rotors 15-20% and are not just for looks. They don't cryo their rotors, but use a process that produces cast in flush radius holes rather than actually drilling the rotors. He said actual drilling of rotors will degrade the steel and make it extremely prone to fatique and warping. FYI. 
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Cross drill: Its not a matter of 'IF' they will crack, its 'WHEN' they will crack....
I had friends with Porsche 993 turbos that is going though his 2nd set of rotors because it crack. Even if its cast with the holes in it, its still more prone to cracks than slots.
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Ive run cross drilled on a few cars... I found that if holes radius well, no cracks formed
sides crossdilled are great in rain... seems to give you better intial bite.. Anybody tried a crossdrilled and slotted rotor??
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You may find increased rotor wear.....>>>>
Based on my experience with the 993 Porsche I owned, the rotor wear will be very uneven but perfestly normal according to the Porsche service manuals. It will eventually look like ~~~~~~~~~
I found replacement at about 30K appropriate based on wear and the degree of ~~~~~. Never noticed any cracking though....
I found replacement at about 30K appropriate based on wear and the degree of ~~~~~. Never noticed any cracking though....
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