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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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Dick ************** 1999 Legacy GT 30th Anniversary Edition 2001 Outback Sport |
#2
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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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Alan 1987 928 S4 (Black) SOLD! 1997 SVX LSi (Ebony) SOLD! 2005 Legacy GT (Silver) [Cobb Stg 2+] SOLD! 1987 928 S4 (Black) SOLD! 2005 Forester XT Premium (Crystal Gray Metallic) SOLD! 2008 Lancer Evolution X MR (Apex Silver) [Cobb Stg 1+] 2015 Outlander Sport 2.4GT AWD (Mercury Gray) 2013 G37xS (Obsidian Black) |
#3
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#4
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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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. Earl .... ... .... ><SVX(*> Subaru Ambassador [COLOR=”silver”]1992 Tri Color L[/COLOR] ~45K (06/91) #2430 1992 Dark Teal LS-L ~184K (05/91) #0739 1992 Claret LS-L ~196K (05/91) #0831 1992 Pearl LS-L ~103K (06/91) #1680 1992 Pearl LS-L ~151K (06/91) #2229 1992 Dark Teal LS ~150K (07/91) #3098 (parts car) 1992 White LS-L ~139K (08/92) #6913 1993 25th AE ~98K (02/93) #164 1993 25th AE ~58K (02/93) #176 1993 25th AE ~107K (02/93) #215 1993 25th AE ~162K (02/93) #223 1994 Laguna Blue Pearl LSi ~124K (1/94) #2408 1994 Laguna Blue Pearl LSi ~144K (10/93) #1484 1994 Laguna Blue Pearl LSi ~68K (10/93) #1525 1994 Barcelona Red LSi ~46K (02/94) #2624 1994 Pearl LSi ~41K (12/93) #1961 1995 Bordeaux Pearl LSi ~70K (02/95) #855 1996 Polo Green LSi ~95K (03/96) #872 1997 Bordeaux Pearl LSi ~55K (08/96) #097 2003 Brilliant Red LS1 Convertible ~29K (04/03) #8951 1999 Magnetic Red LS1 Coupe ~33K (04/99) #6420 My Email | Old Locker | New Locker | Picture of 15 of the 19 |
#5
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Quote:
- Ca$h |
#6
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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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1992 LS Touring (6/91) - Currently undergoing a five speed swap Black over Claret with spoiler; 235,000 miles; Mods: 2002 Legacy 5 speed, ACT Pressure Plate, Excedy Clutch, Short Throw Shifter, Aussie Powerchip 1992 LS Touring (6/91) Black over Claret with 2.5" setback spoiler; 202,000 miles; Mods: B&M Cooler 1994 LSi (4/93) Bordeaux Pearl; 198,000 miles; Mods: Weight reduction. 1969 Mustang GT Convertible 1970 Mustang Convertible 2000 Ford Excursion Sola lingua bona est lingua mortua. My Locker |
#7
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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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Randy Johnson 3rd Registered Member 02-21-2001 First Member to Reach 10,000 Posts First to arrive at the very first Reading Meet Subaru Ambassador 1992 SVX PPG Pace Car Replica 110+k 1993 White Impreza L 240+K miles 2001 Legacy Outback Limited Sedan 250+K miles 2013 Deep Indigo Pearl Legacy 3.6R 49+K miles "Reading is my favorite Holiday" Mike Davis -- at Reading VI |
#8
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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. |
#9
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Re: Drilled/slotted Rotors
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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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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#10
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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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#11
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Randy Johnson 3rd Registered Member 02-21-2001 First Member to Reach 10,000 Posts First to arrive at the very first Reading Meet Subaru Ambassador 1992 SVX PPG Pace Car Replica 110+k 1993 White Impreza L 240+K miles 2001 Legacy Outback Limited Sedan 250+K miles 2013 Deep Indigo Pearl Legacy 3.6R 49+K miles "Reading is my favorite Holiday" Mike Davis -- at Reading VI |
#12
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Ahhhhh . . . mystery unraveled. Thanks for the info, guys.
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Dick ************** 1999 Legacy GT 30th Anniversary Edition 2001 Outback Sport |
#13
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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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Alan 1987 928 S4 (Black) SOLD! 1997 SVX LSi (Ebony) SOLD! 2005 Legacy GT (Silver) [Cobb Stg 2+] SOLD! 1987 928 S4 (Black) SOLD! 2005 Forester XT Premium (Crystal Gray Metallic) SOLD! 2008 Lancer Evolution X MR (Apex Silver) [Cobb Stg 1+] 2015 Outlander Sport 2.4GT AWD (Mercury Gray) 2013 G37xS (Obsidian Black) |
#14
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While we're here - can cryogenic rotors be "turned", or is this a REALLY stupid question? Ron(duh?)
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Good s**t happened. 69 was worth the wait. '92 stock semi-pristine ebony - 160K '96 Grand Caravan - 240K '01 Miata SE - 79K '07 Chrysler Pacifica - 60k - future money pit. |
#15
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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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