NZConvertible

While the benefits of cross-drilling and slotting for an average street car are debatable, to imply you have a better knowledge of braking systems than Porsche might be getting a bit above yourself. The last thing Porsche needs to do sell more cars is drill their brake rotors for looks. Porsche's long-standing braking criteria for all their cars is six full-pressure 150mph to 30mph brake applications with no cooling periods in between (the numbers are from memory but will be close). There must be no fade at all from this punishment. It's a fair bet that Porsche do use modern brake compounds, but they still feel they need to drill their rotors. There is also extensive use of slotted and/or drilled rotors in top level motorsport, so there are a lot of people out there with more experience than you and I who seem to think they are necessary.

RETed

The thing with Porsche is that with the rear engine configuration, they can get away with a lot of "weird" designs that won't normally work with a typical front engine design car.&nbsp For example, rear brakes do a LOT MORE WORK on a Porsche than front-engine platforms.&nbsp If you've never experienced braking in a Porsche, you're going to go through an EYE-OPENING experience!

I didn't mean to imply I'm above Porsche engineers, but the currrent, top brake designers and engineers will pick apart any arguments for drilling or slotting.&nbsp Check out the Brake Handbook (by HP Books?) or any number of brake books written for auto enthusiast.&nbsp Drilling was something of a "fad" years ago, and my point about unspring weight savings was a valid concern for some systems.




-Ted

djantlive

I know how to operate a lathe but I think it will be pretty hard to turn a cross drilled or slotted rotors. I say again, it's probably not impossible but very hard. Lathing is not all that easy if you want to make a perfectly smooth surface. I really don't think turning such rotor would be a good idea.

Having said that, Porsche owners probably get their rotors replaced when they change the pads. The reality is that FD's stock brakes are excellent for street. It stops shorter than the previous generation 911. Unless you go tracking, it's probably scores more points in looks than stopping.

If you do get slotted or x drilled rotors, get them from a know brand. Mazdaperformance.com (use the ad link on this forum) sells them for $129-149 each. Don't buy something cheap that will crack...

FEDREX

I have Powerslots on the front with Hawk HPS pads. Average dust, no noise or squeal. The rotors have been on the car for about 20k and are holding up fine.

z-man

i have brembo crossed drilled rotors for an 86 N/A. they cost me $75 a peace and an extra $15 dollars a peice for cadium plating so they wont rust. i got them at www.pureperf.com. as far as braking goes, i had a set on my talon and i noticed a difference. i had a problem with stopping fast at high speeds. my brake fluid would start to bubble because it got so hot. after i put the crossed drilled rotors on the probem went away.

just my $0.02

RETed

http://www.mr2sc.com/websites/articl...iction_s3.html

(bottom section)

READ IT!&nbsp Or you gonna say these guys don't know what they are doing also?



-Ted

NZConvertible

Everything they say makes good sense except the bit in bold. A larger diameter rotor means you are applying the clamping force further from the rotational axis, in effect applying a greater braking "torque", providing stronger braking. Basic physics.