Slotted rotors?, Advantages and availability question |
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Slotted rotors?, Advantages and availability question |
Sawfish |
Jan 11 2011, 10:34 PM
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#1
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Newbie Group: Members Posts: 43 Joined: 28-January 09 From: San Diego Member No.: 9,990 Region Association: Southwest Region |
Dreaming of upgrades for my 914 was wondering about the advantages of slotted brake rotors and also are there any manufacturers who build them for our cars. I have read that the 914-6's had them. Does anyone know a source or have opinions?
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Dave_Darling |
Jan 12 2011, 12:52 AM
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#2
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914 Idiot Group: Members Posts: 14,986 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
The Sixes did not have slotted rotors. The Sixes had vented rotors, which are a whole 'nother kettle of fish.
A slotted rotor is a stock rotor (in our case, a solid rotor) that someone cut grooves into the wear surface of the rotor. This can help wipe water away from the face of the pad, and can also help get hot material away from the face of the pad. With modern pad compounds, it is not usually a whole lot of help. In the Olden Days, pads used to out-gas more when heated up and it could cause a problem where the pedal was nice and firm and yet the brakes didn't slow you down. Pads are much better today. A vented rotor is kind of like two solid rotors next to each other, with an air space in between. Some of that space is bridged by metal, in order to hold everything together. The rotor is much thicker (over 1" thick, usually), and has more thermal mass (due to having more mass!) and has that air passage so that air can travel through the rotor taking heat with it. It helps keep brake temperatures down when the brakes are used hard. You can run vented rotors on the front of a 914, but this is generally done by swapping in a 911 front suspension. If you want to keep the four-bolt wheels, you may be able to find some of the billet hubs that were made a while back. You'll still have to swap out the calipers, as they won't fit over the vented rotors with enough room for a real brake pad. --DD |
DanT |
Jan 12 2011, 12:57 AM
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#3
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Going back to the Dark Side! Group: Members Posts: 4,300 Joined: 4-October 04 From: Auburn, CA Member No.: 2,880 Region Association: None |
If your car is a street car only...then slotted or vented rotors will get you nothing but a thinner wallet (IMG:style_emoticons/default/smile.gif)
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ArtechnikA |
Jan 12 2011, 05:02 AM
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#4
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rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
If your car is a street car only...then slotted or vented rotors will get you nothing but a thinner wallet (IMG:style_emoticons/default/smile.gif) All my street vehicles have slotted rotors. I like them, especially in the rain. The water film is wiped off instantly. I think it also helps keep sand and grit from getting trapped under the pads. In my experience, the slotted rotors develop fewer wear grooves. That said, I don't know about availability of off-the-shelf slotted rotors for /4 applications, which also contain the bearing carriers (front). Any competent machine shop should be able to do it but there's an art to it (how many? how deep? spaced regularly or nonsymmetrically?) and this is _no_ place to be experimenting. They'll need to be balanced after machining. And there is no getting around the fact that any machining is removing mass of which 914's have no surplus... Despite my initial reservations, I'm also a convert to cryo-treated rotors. A full shipset of cryo treated slotted rotors and good pads is expensive and as DanT observes, probably substantial overkill for the average street 914. If it doesn't rain much where you live, you'll probably never notice any benefit. (Pads and rotors for the Titan was around $1k and I got group-buy pricing on the pads. But the Titan has a reputation for undersized brakes and I felt an upgrade was in order. For the Subie it was about $800.) |
jt914-6 |
Jan 12 2011, 06:38 AM
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#5
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Driving & working on teeners 41 years Group: Members Posts: 1,786 Joined: 3-May 08 From: Bryant, Arkansas Member No.: 9,003 Region Association: South East States |
Since I use my car for DE's I have cyro/slotted rotors all around. Am using Carrera rotors F & R with C2 front calipers and C2 Turbo calipers on the rear. I have used drilled rotors in the past, but they will start to crack around the holes when they get older....
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Sawfish |
Jan 12 2011, 07:29 AM
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#6
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Newbie Group: Members Posts: 43 Joined: 28-January 09 From: San Diego Member No.: 9,990 Region Association: Southwest Region |
Thanks for the responses and feedback!
I love this site (IMG:style_emoticons/default/smile.gif) |
6freak |
Jan 12 2011, 08:31 AM
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#7
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MR.C Group: Members Posts: 4,740 Joined: 19-March 08 From: Tacoma WA Member No.: 8,829 Region Association: Pacific Northwest |
If your car is a street car only...then slotted or vented rotors will get you nothing but a thinner wallet (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/smile.gif) ...nothing but bling on a street car |
IronHillRestorations |
Jan 12 2011, 12:35 PM
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#8
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I. I. R. C. Group: Members Posts: 6,719 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None |
Probably not adviseable for solid 914-4 rotors, there's not enough thickness for slotting or drilling.
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RickS |
Jan 12 2011, 09:54 PM
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#9
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Senior Member Group: Members Posts: 1,408 Joined: 17-April 06 From: 'False City', WA Member No.: 5,880 Region Association: None |
Your user profile doesn't specify the year of your car. Anyway these guys sell vented/slotted for 4 lug 914s. I have purchased electric window motors from these guys for my 911 and they were brand new and excellent: http://www.partsgeek.com/catalog/1975/pors...rake_rotor.html
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sean_v8_914 |
Jan 13 2011, 02:49 AM
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#10
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Chingon 601 Group: Members Posts: 4,011 Joined: 1-February 05 From: San Diego Member No.: 3,541 |
hijack warning, achtung!
rules...points...non stock brakes FG bumpers, fg deck lids. "every gram must be accelerated, cornered and braked" less weight creates less brake heat less weight accelerate faster less weight wears tires less less weight corners faster less weight uses less fuel |
Sawfish |
Jan 13 2011, 07:32 AM
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#11
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Newbie Group: Members Posts: 43 Joined: 28-January 09 From: San Diego Member No.: 9,990 Region Association: Southwest Region |
hijack warning, achtung! rules...points...non stock brakes FG bumpers, fg deck lids. "every gram must be accelerated, cornered and braked" less weight creates less brake heat less weight accelerate faster less weight wears tires less less weight corners faster less weight uses less fuel Thanks Sean! great advice as always (IMG:style_emoticons/default/pray.gif) . Now if I can Just figure out where I sit in this new points system (IMG:style_emoticons/default/smile.gif) |
sean_v8_914 |
Jan 13 2011, 08:08 AM
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#12
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Chingon 601 Group: Members Posts: 4,011 Joined: 1-February 05 From: San Diego Member No.: 3,541 |
trophies for 2011 will be classed same as last year. new rules dont apply till 2012
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