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Old 07-15-2007, 01:14 AM   #1
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Default slotted rotors for gxp?

I seen these rotors on ebay thought I would post them here to get everyones opinions

http://cgi.ebay.com/ebaymotors/Ponti...mZ330145931753

I read in a previous post about drilled rotors not being good so I thought maybe these ones were good because you can order them just slotted.

I emailed the seller as to the size of the rotors because correct me if I'm wrong but the gxp has 14" rotors and these say they are specifically for the gxp.
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Old 07-15-2007, 01:27 AM   #2
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What have people got against drilled rotors? I've run them on my 95 for years and they came standard on my 05 Grand Prix GXP, and trust me, even braking from the top speed of around 250km/h, they WILL NOT warp.
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Old 07-15-2007, 02:48 AM   #3
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Most drilled rotors on the market are drilled AFTER hardening. They will crack. Many brake shops will not turn drilled rotors.

Drilling rotors decreases braking surface area. The only way to overcome this is increase your rotor diameter IF the holes were cast into the blank before machining/hardening.

Because of the import tuner market, the 'cosmetic' aspects of drilled rotors has become so rampant, there isn't a shop within 50 miles of me that will turn drilled rotors any more. Multiple rotor failures have been blamed on these shops, so they simply won't deal with them any longer.

'drilled' rotors as we know them in NASCAR or other professional racing leagues are actually cast into the blanks, then hardened, then machined. They are thrown away after every race because of cracking.

Buy slotted. Not drilled. Try a search here on this Forum. There'* hundreds of posts covering this information.

Your braking WILL be reduced due to the lack of surface area, and your rotors WILL micro-crack around every hole. It'* only a matter of time.

In addition, if you trust your life and the safety of your family and the people around you to a no-name brand of 'performance' brake rotor, you will regret it.

Buy NAME BRAND at the best price you can get. Don't buy any unknown braking component for ANY price.
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Old 07-15-2007, 02:59 AM   #4
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I didn't know about the cracking issues. I've actually turned my own drilled rotors once. It makes sense, though. I've only ever used PBR before, though, which is supposed to be quality stuff. I agree that you get what you pay for. IIRC, the factory GP GXP brakes are PBR too.
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Old 07-15-2007, 03:58 AM   #5
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I still dispute the argument that drilled rotors are less effective.
My own experience with drilled rotors on my old 95 SSEi was very positive. I noticed no decrease in braking power, and a huge improvement in fade resistance. I used Powerstop rotors, which are cast with the holes already in place.
I delivered pizza in that car, which involved considerable stop and go and "spirited driving". The only time I ever noticed even a trace of fade was after an extremely fast run down my favorite road in Southeaster Ohio, a nasty twisty, hilly run through ridges and ravines. If that road didn't fade them beyond usability, nothing will.

Buy quality rotors from a good company, and you'll have no problems. As far as turning the rotors, don't. Cross-drilled rotor should never be machined, ever. Although, I refuse to have rotors turned, period, myself. Too many places scrfew it up, even on regular rotors. Just replace the damn things. Besides, if you wear a set of rotors out in less than 4 pad changes, somethings wrong. That'* not a huge expense, when you think about the time it takes to wear out a good set of pads.
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Old 07-15-2007, 11:16 AM   #6
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Your increase in braking was from the quality of the rotor and it'* ability to dissipate heat, which is due to the thickness of each rotor face, the hardening process, and even the alloy used. In addition, you changed pad composition at the same time.

Had you purchased the same rotor without the holes, you would have had MORE braking.

Fade resistance can be achieved with proper pad selection. It can also be achieved by buying slotted rotors, which have the ability to vent the pad gasses as they heat up to the edge of the rotor. Slots can't do this as well, as they vent to the hole that is blocked on the other side by another pad. Slots also have the great ability to vent water to the outside edge and expel it. Holes can't do that either.

The holes have to 'wait' to vent the gasses and water until after they're past the pad surface.

Braking is achieved by friction. Friction is greater with given pad and rotor materials by surface area. Slots do decrease this by a small amount, but not nearly by as much as holes decrease it.
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