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Author
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Topic: WHY Blank rotors are better than cross drilled and/or slotted
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19gt93
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Member # 5072
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posted
 
 
FYI
Ok I'm hearing a lot of conjecture, and people are STILL blowing money on shitty rotors, so I will tell you all why blank rotors are better.
The reason for the creation of cross drilled rotors initially was to remove the "gasses" from the brake pads. HOWEVER, most of your modern brake pads (Axxis metal, AEM semi-ceramic) do NOT produce gasses when heating. This was on bad brake pads used in the 1950s and 1960s. Back then, asbestos was also used, and we dont use that either.
The other reason is so called heat dissapation. I don't have my physics and thermo books with me, but the logic is that the holes in the rotor are suppose to allow the brake pad to cool. So...air gets into the rotor from the inside of the vents. If you have a back rotor which is solid, air gets into these holes how? If your stopped, you are leaving air inside these holes sandwiched between the pads, thus creating air with a rising temperature. Its increasing in pressure from the heat, which I guess you "could" call a gas that would affect braking. So the cross drilled rotors do not remove any gasses formed by brake pads (because there are none created anymore) but could possibly inhibit the creation of "hot spots".
Cross drilled rotors have LESS contact area because of the holes.
But if the rotor is cooler, its better, right? Well no, because these rotors are not cooler. THe heat is generated from the pad/rotor contact. What removes heat the most effectively? When stopped or moving, the pad transfers heat into the rotor because its made of cast iron. the rotor has a lot of surface area and even vanes in it. But the little holes allow air in this surface contact, and you can transfer more heat into a solid big ass chunk of cast iron more than you can into the air. Don't believe me? Touch some steam at 150 degrees, then touch a piece of hot metal which is at 150 degrees. Which burns your hand? the metal. So let the heat transfer into the metal, because since it has so much more surface area, dissapates better.
Safety!!
Cross drilled rotors can crack! I have seen them!!
Even racing teams will reccomend AGAINST cross drilled rotors:
http://www.livermoreperformanc.COM
Companies that sell cross drilled rotors that are redrilled may not be structurally sound. I have actually seen pictures of rear Integra rotors that have had hairline cracks turn into the rotor actually breaking apart!
Do your homework. Even Porsche and Ferrari will admit that the cross drilled rotors they use are for looks. So if you are one of those kids who thinks the little holes look cool, get a name brand drilled rotor like Ferrari does. The REASON Ferrari's 'holed' rotors are alright to use is because they are CAST with the holes in them, so they are not actually drilled into cast iron rotors. Cheap drilled rotors are not safe, and even the good ones are not necessary. Why do Ferrari do it? People THINK they want it, and it sells. If you don't believe me, go into the business world. You will learn that pretty soon, you can sell utter shit if people THINK its better.
[ December 07, 2005, 09:30 PM: Message edited by: 94DropTop ]
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2 hemi's and a 5.0
Posts: 242 | From: BAYAREA | Registered: Nov 2004
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PWR HNGRY 302
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Member # 6000
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Whoa ![[Eek!]](eek.gif) I would of never thought that, I was actually planning on getting some slotted/cross drilled rotors. Looks like I should do more homework before buying my parts.
--your link isn't working--
[ December 07, 2005, 09:28 PM: Message edited by: PWR HNGRY 302 ]
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Posts: 2655 | From: SF Bay Area | Registered: Sep 2005
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two-gun kid2
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Member # 5891
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posted
ya cross drilled rotor tend to crak inbetween the holes when they undergo lots of heat and stress
Posts: 5566 | From: Hayward,Ca | Registered: Jul 2005
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losbadgts
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Member # 4394
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posted
then why a lot of sport car this days come with drilled rotos.
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Why pretent someone u are not, everyone else could see it.
Posts: 3625 | From: redwood city | Registered: Apr 2004
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kingmoochr
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Member # 5834
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posted
quote:
Originally posted by losbadgts:
then why a lot of sport car this days come with drilled rotos.
quote:
Originally posted by 94DropTop:
Do your homework. Even Porsche and Ferrari will admit that the cross drilled rotors they use are for looks.
Posts: 881 | Registered: Jul 2005
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1Sicgt
CAFords OG
Member # 714
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posted
The best design is a slotted rotor. It does allow for cooling yet is open at the end so gas does escape. Plus it doesn't need the full surface are of the pad for contact. A slotted rotor actually cuts a very fine layer of pad everytime you apply the brakes. This helps the pads from glazing, which cuases brake fade. Solids do offer more surface area, but under extreme heat they glaze faster, and start to slip, and loose some of the breaking stregnth.
[ December 07, 2005, 11:52 PM: Message edited by: 1Sicgt ]
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Posts: 8145 | From: Hitting the Apex | Registered: Jan 2002
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wilit
Mustang Messiah
Member # 3367
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posted
quote:
Originally posted by 94DropTop:
Even racing teams will reccomend AGAINST cross drilled rotors:
http://www.livermoreperformanc.COM
Where on that link does it reccommend against cross drilled rotors? I looked quickly but didn't see it.
quote:
Originally posted by 94DropTop:
Do your homework. Even Porsche and Ferrari will admit that the cross drilled rotors they use are for looks.
I'd really like to see where this info came from? Got a quote directly from Porsche or Ferrari?
I'm not downplaying anything you said. It's all valid info, but if you're going to post something like this, you should provide some direct quotes from more reputable sources than some speed shop in Livermore.
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"If a man hasn't found something worth dying for, he isn't fit to live." - Martin Luther King Jr.
Posts: 4793 | From: 37.78514° North 122.40100° West | Registered: Oct 2003
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1FAST89GT
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Member # 5071
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posted
quote:
Originally posted by 1Sicgt:
The best design is a slotted rotor. It does allow for cooling yet is open at the end so gas does escape. Plus it doesn't need the full surface are of the pad for contact. A slotted rotor actually cuts a very fine layer of pad everytime you apply the brakes. This helps the pads from glazing, which cuases brake fade. Solids do offer more surface area, but under extreme heat they glaze faster, and start to slip, and loose some of the breaking stregnth.
solids also squeak hella from that glazing as apose to slotted/cross drilled
Posts: 4915 | From: VALLEJO | Registered: May 2004
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1Sicgt
CAFords OG
Member # 714
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posted
quote:
Originally posted by wilit:
quote:
Originally posted by 94DropTop:
Even racing teams will reccomend AGAINST cross drilled rotors:
http://www.livermoreperformanc.COM
Where on that link does it reccommend against cross drilled rotors? I looked quickly but didn't see it.
quote:
Originally posted by 94DropTop:
Do your homework. Even Porsche and Ferrari will admit that the cross drilled rotors they use are for looks.
I'd really like to see where this info came from? Got a quote directly from Porsche or Ferrari?
I'm not downplaying anything you said. It's all valid info, but if you're going to post something like this, you should provide some direct quotes from more reputable sources than some speed shop in Livermore.
Just as a bit of info. Livermore Performance, is not a regualr speed shop. They race cars, and sell race parts for people who race there cars. They have a ton of knowledge, and are very reputable. Aside from that, the drilled rotor is correct. At sema, when we were talking with baer brakes, they said basically the same thing. People buy the drilled rotor for STREET cars. Not track abused cars. They WILL NOT sell you drilled rotors if you plan on doing track duty on their brake systems. There is too much liability for them to crack and fail.
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14 Focus TS ST3 full Stg3, ready for bigger Turbo
2003 Cobra Track Car
Posts: 8145 | From: Hitting the Apex | Registered: Jan 2002
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19gt93
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Member # 5072
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posted
ya just came across it just wanted every one to see it
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2 hemi's and a 5.0
Posts: 242 | From: BAYAREA | Registered: Nov 2004
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166 Merlo
FELONY
MOTORSPORTS
Member # 1549
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posted
isn't that plagurism?
Idunno about anyone else but I'm gettin me some big ass 13" cross drilled and slotted rotors when i get the money. That shit looks sick to me. ![[Whoo Whooooo!]](graemlins/woowoo.gif)
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Posts: 3954 | From: Thebay | Registered: Jul 2002
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two-gun kid2
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Member # 5891
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posted
now my ques is what are you guys doing in a honda forum?
Posts: 5566 | From: Hayward,Ca | Registered: Jul 2005
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PWR HNGRY 302
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Member # 6000
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posted
quote:
Originally posted by 87:
isn't that plagurism?
Idunno about anyone else but I'm gettin me some big ass 13" cross drilled and slotted rotors when i get the money. That shit looks sick to me.
That shit does look tight. I was planning on geting some cross drilled and slotted rotors for my car but I think i should do a little more research before i do.
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87 Fox- Restoration in progress
2014 Tacoma DCLB MGM
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Posts: 2655 | From: SF Bay Area | Registered: Sep 2005
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BlackNGold
CaliforniaFords.com
Moderator
Member # 655
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posted
quote:
Originally posted by wilit:
quote:
Originally posted by 94DropTop:
Even racing teams will reccomend AGAINST cross drilled rotors:
http://www.livermoreperformanc.COM
Where on that link does it reccommend against cross drilled rotors? I looked quickly but didn't see it.
quote:
Originally posted by 94DropTop:
Do your homework. Even Porsche and Ferrari will admit that the cross drilled rotors they use are for looks.
I'd really like to see where this info came from? Got a quote directly from Porsche or Ferrari?
I'm not downplaying anything you said. It's all valid info, but if you're going to post something like this, you should provide some direct quotes from more reputable sources than some speed shop in Livermore.
Yeah, I'm with you on this one...I've seen my share of cheap cross drilled rotors being cracked and yet I've seen many Brembo rotors that were cross drilled that have lasted many track events...
1sicgt~That's pretty interesting that the Baer guys are said they recommend cross drilled only for the street....You almost always see Baer brakes crossdrilled....
I can understand a lot of points and I'm a little confused myself as to which rotors are better...I know that FACTS...I know F1 don't use cross drilled rotors, I also know it takes 5 months to make an F1 rotor which is made carbon...I don't think you can really compare those brakes to any street or even to most forms of racing(CART still use steel)....
As for Ferrari and Porsche, I CAN NOT honestly see them using crossdrilled for looks...These cars are high performance automobiles, designed to be the best...I'm sure crossdrilled works best for their set ups...
Have you ever seen a 360 Challenge car?...I don't think these are for looks...
http://www.fast-autos.net/ferrari/stradale29.html
Check out this GT3 Porsche with cross drilled...
http://www.bahrainicars.com/forums/showthread.php?t=9643
[ December 08, 2005, 01:32 AM: Message edited by: BlackNGold ]
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-SLOWER TRAFFIC KEEP RIGHT-
Posts: 5132 | From: Bay Area, CA | Registered: Dec 2001
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CobramanPhil
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Member # 2170
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posted
quote:
Originally posted by two-gun kid:
now my ques is what are you guys doing in a honda forum?
I was looking up information on some slotted rotors for my cobra (not drilled..just slotted) and the big quote was on the middle of the browser search ![[Razz]](tongue.gif)
Just my $.02....I really have difficulty in believing that pads (newer kinds) will not have to go through a "de-gas" period..especially new pads say in between a race round. It is the burnoff of the binder, fillers, crapola stuff, and other materials. The gas needs a place to go at the surface of the pad and the holes (or slots as in slotted rotors) allow for that path. Without an area of "de-gas" escape there is a pressure generated by the escaping gas that "pushes" in the opposite direction of the braking force. It sort of feels like the brakes have faded after one or two laps when they really haven't and your going wtf is the deal with these crappy brakes ![[Confused]](confused.gif)
My suggestion is to go with rotors and brake pads that complement each other. Whether slotted, drilled, or both there is an advantage to having a system with all the correct parts. Throwing something like super duper non-street hawk pads on your stock rotors is just asking for trouble. Getting the whole package is the best way as braking has a lot of variables and parts that make it work. For an everyday street car stick with slotted. Your not going to experience the race track forces encountered as in a drilled rotor might be best at in those condtions.
[ December 08, 2005, 01:33 AM: Message edited by: CobramanPhil ]
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Posts: 1016 | From: California, Bay Area | Registered: Dec 2002
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racercosmo
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Member # 1864
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posted
I don't know what the official Porsche line is, but our GT3s came with slotted rotors, no holes. We did use drilled rotors sometimes at short races when it was really wet. We did not have drilled rotors on the cars for the 24 hour races.
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Beauty is in the eye of the beer holder
Posts: 973 | From: Marin | Registered: Sep 2002
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NonOpSlow2V
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Member # 6111
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posted
quote:
Originally posted by PWR HNGRY 302:
quote:
Originally posted by 87:
isn't that plagurism?
Idunno about anyone else but I'm gettin me some big ass 13" cross drilled and slotted rotors when i get the money. That shit looks sick to me.
That shit does look tight. I was planning on geting some cross drilled and slotted rotors for my car but I think i should do a little more research before i do.
yeah i agree it does look fuckin sick...im gettin them on my gt i guess for looks,,,thats about it...but now i do understand how it works...so when my cobra comes around i'm gonna look more into performance then looks
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Posts: 2139 | From: San Francisco | Registered: Oct 2005
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Wolfie351
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Member # 651
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posted
You can't make a blanket statement that ALL slotted or drilled rotors are bad. People have a tendency to buy the cheapest stuff out there and those are the ones that won't last beyond one open track session. The last time I was in the pits at a Sears Point race, 99.9% of the cars had slotted rotors. I'm not about to pay the major bucks for those high priced drilled rotors, so it's plain for me!
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1985 Mustang GT: 351W, Griggs, Baer, etc etc
Posts: 1214 | From: South Bay | Registered: Dec 2001
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SteveL
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Member # 1241
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posted
quote:
I really have difficulty in believing that pads (newer kinds) will not have to go through a "de-gas" period
It may and should be part of the bed-in process when changing pads.
The issue here is heat. It's unlikely you'll generate enough heat in the rotor with OEM brake pads driving on the street to crack a drilled rotor. Go to agressive pads and heavy braking and good chance you'll crack even a slotted rotor. At that point it's time to consider brake cooling ducts. [ I cracked a 14" Alcon slotted, not drilled rotor with Hawk Blues and no cooling ducts while at Thunderhill. ]
It's difficult to predict at what temperature a particular type or brand of rotor will fail but you'll know when you've really heated up the brakes. You'll experience brake fade.
[ December 08, 2005, 04:43 PM: Message edited by: Roush #92 ]
Posts: 578 | From: San Jose, CA | Registered: May 2002
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uncle bill
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Member # 3953
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posted
not claiming to be an expert, but ive thrown away more than my share of busted rotors and that includes the cryogenically treated ones as well. front rotors are vented for cooling because they take the most abuse. drilling them only makes them lighter and nicer to look at. heat does cause fade, mainly do to a brake system smaller than is requierd to do the job. (bigger is better). rotors crack, mainly do to lack of a proper cool down, when the car stops, the rotors continue to cool, but unevenly, the heat stays around the caliper, no air flows between the pads, and when the metal is heated and cooled it expands and contracts.(uneven cooling causes busted rotors)if your track time runs out, roll your car a foot or two every minute in the pits, it saves the rotors and your bank account.
[ December 11, 2005, 01:45 PM: Message edited by: uncle bill ]
Posts: 415 | From: antioch | Registered: Dec 2003
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94gt
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Member # 3060
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posted
quote:
Originally posted by Wolfie351:
You can't make a blanket statement that ALL slotted or drilled rotors are bad. People have a tendency to buy the cheapest stuff out there and those are the ones that won't last beyond one open track session.
Think about it, he quoted it from a honda forum... (someone provided a link) I'd say a good majority of the honda "racing" crowd uses the cheapest crap found.
1st step, buy honda.
2nd step, buy crap parts (including HUGE wing)
3rd step, add stickers to your content.
4th step, take your 'new' honda out and 'beat' mustangs and camaro's. ![[Wink]](wink.gif)
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Posts: 5777 | From: Beavercreek, OH | Registered: Jul 2003
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