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  #1  
Old 09-23-2002, 05:59 PM
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Drilled/slotted Rotors

I've searched and can't find the answer - how exactly does drilling and slotting improve performance of a brake rotor?
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Old 09-23-2002, 08:20 PM
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helps in cooling the hot rotor. i'd say slotted are better, because drilled holes weaken the rotor. they look cool, but unless you can afford to change the rotors as often as professional racecars do, they're probably not a good idea for the street. Porsche has the holes cast into the rotor during manufacture making them stronger, but they are pricey $$$$.
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  #3  
Old 09-23-2002, 08:23 PM
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I just bought these from ebay:

http://cgi.ebay.com/ebaymotors/ws/eB...tem=1854454561

Any good???
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  #4  
Old 09-23-2002, 08:26 PM
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Other rotors are dimple drilled. In other words, they only drill 1/8 of an inch into the rotor (not all of the way through) which does not weaken the rotor as much as cross drilling. Some are slotted and dimple drilled. RaceConcepts have rotors that are that way. Just my .02!
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  #5  
Old 09-24-2002, 12:49 PM
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Quote:
Originally posted by Landshark
Porsche has the holes cast into the rotor during manufacture making them stronger, but they are pricey $$$$.
Little FYI. On the porsche factory RACECARS they REMOVE these 'drilled' rotors and install NON DRILLED NON SLOTTED rotors. Why? More surface area for the pad to bite on, less chance for it to warp.

- Ca$h
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  #6  
Old 09-24-2002, 01:07 PM
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<<On the porsche factory RACECARS they REMOVE these 'drilled' rotors and install NON DRILLED NON SLOTTED rotors. Why? More surface area for the pad to bite on, less chance for it to warp.>>

Don't forget they also use rotors that are about 5cm wider in diameter than OEM and about 2cm wider spacing between discs. They also use larger surface area pads.

Doug
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  #7  
Old 09-24-2002, 01:26 PM
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Quote:
Originally posted by $VX


Little FYI. On the porsche factory RACECARS they REMOVE these 'drilled' rotors and install NON DRILLED NON SLOTTED rotors. Why? More surface area for the pad to bite on, less chance for it to warp.

- Ca$h
I agonized over the whole "drilled and slotted" issue. I was vehemently opposed to these rotors. Basically, I couldn't see how they would be an improvement. First of all, logically, when you have odd shaped surfaces like holes or slots, one could assume that you would be creating little "graters" that would shear off friction materials, causing pads not to last as long. I had also heard of drilled rotors cracking due to heat disappation around holes, weakening the rotors. I basically poo poo'd them.

Then, I got a chance to purchase a set of drilled and slotted's for less than stock, and decided to do more research. Turns out that the sources I read were also against Drilled and slotted or drilled or slotted rotors . . . for RACING. However, they saw improvements in performance for the everyday driver and practically all reviews and articles gave them a thumbs up for the average commuter car. Believe me, I was "floored" as I read the various reviews. Needless to say, I bought the D/S rotors. I've yet to put them on the car (figured I'd wait for the current pads to wear out), although, the folks at the tire shop said I needed rotors.

I bought the "Evil Twin" with drilled rotors already installed and the car seems to have better stopping power, but, this could simply be a difference in the rotors on "Patience" being old and the rotors on "Evil Twin" being relatively new. We shall see, when I make the switch on the other car. I also intend to get SS brake lines for both cars.
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  #8  
Old 09-24-2002, 05:13 PM
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Here's a simple explanation of the slots.

http://www.appliedrotortechnology.com/index.htm

If you want to see what the SVX ones look like check my personal locker.
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  #9  
Old 09-24-2002, 06:39 PM
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Re: Drilled/slotted Rotors

Quote:
Originally posted by Dick Young
I've searched and can't find the answer - how exactly does drilling and slotting improve performance of a brake rotor?
To put it in the short version. The slotting is to allow air or gas to escape, out from between the pad and rotor. Otherwise the gas will float the pad on the disk to produce fade, this is mainly for racing as the pads won't get that hot, under normal road use. For road use, the slotting will help, to reduce the squealing, that happens when air is trapped between the pad and rotor.

The drilling is to allow water to escape from between the pad and rotor. Used on mainly on motor cycles because the disks are open to the rain. It allows the water to be squeezed into the holes, away from the surface of the disk. The bike riders will know the feeling, of hitting the front brake in the wet, to have no reaction, so you squeeze harder, the water goes, the brake locks and down the road you go.

On our road cars the disk is shrouded by the wheel, so the water is not a problem and the holes are not needed. Only solid disks should be drilled. Drilling vented disks interferes with the cooling, that the vents are designed to do. You would not drill holes in the impeller housing of a turbo charger as it would interfere with it's action. The venting between the surfaces works the same as the impeller, to pump air from the center of the disk to the outside edge to provide even cooling of the disk.

Though you can get them in 4 different colours and with blue callipers they work fantastic at pulling a crowd.

Harvey.
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  #10  
Old 09-25-2002, 04:23 AM
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Randy,

Instead of naminig your SVXes 'Patience' & Evil Twin', how about
'Patience' and 'Imprudence' after 'Patience and Prudence'. Afterall , you were a DJ.
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Old 09-25-2002, 08:34 AM
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Quote:
Originally posted by LarryIII
Randy,

Instead of naminig your SVXes 'Patience' & Evil Twin', how about
'Patience' and 'Imprudence' after 'Patience and Prudence'. Afterall , you were a DJ.
Hopefully, I'm finished putting money into them for a while. If they begin to give me any trouble, I'll re-name them "Dumb and Dumber."
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  #12  
Old 09-25-2002, 03:04 PM
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Ahhhhh . . . mystery unraveled. Thanks for the info, guys.
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  #13  
Old 09-25-2002, 05:41 PM
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Quote:
Originally posted by $VX


Little FYI. On the porsche factory RACECARS they REMOVE these 'drilled' rotors and install NON DRILLED NON SLOTTED rotors. Why? More surface area for the pad to bite on, less chance for it to warp.

- Ca$h
i'm looking at a picture of a 962c factory racecar right now and it has "drilled"(cast hole) rotors. those idiots - what are they thinking!?!?!
the new rotors on the 911 twin are ceramic - don't know if they use them for factory racing, though. i'm guessing yes.
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Old 09-25-2002, 07:50 PM
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Question

Quote:
Originally posted by SVX_MY_BABY
Here's a simple explanation of the slots.

http://www.appliedrotortechnology.com/index.htm

If you want to see what the SVX ones look like check my personal locker.

While we're here - can cryogenic rotors be "turned", or is this a REALLY stupid question?

Ron(duh?)
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Old 09-25-2002, 08:31 PM
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From what I've read Ron they can be turned. Supposedly the freezing goes 'to the bone', so to speak.

At first I thought they might be on to something, but the more I think about it the more I think that they're probably as good as placing magnets around your gas line. I guess my biggest problem is that warping is caused by density variations and freezing isn't about to cure that. A better process in casting them would be the ticket. But the manufacturers are selling them like hotcakes at ridiculous prices already, why should they change anything?
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