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Drilled vs. Slotted vs. Blanks Discussion
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Old 04-14-2010, 07:46 AM   #11
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Originally Posted by NW OBS View Post

That's funny almost every brake disk in the Mercedes-Benz and Porsche line up are 'drilled' Somebody better go warn them that they are not designed for daily drivers!!!
you know whats even more funny

a few minutes online gave me the 60-0 times for a SL550 Mercedes, it was 115 feet

a bone stock 2000 VW Golf, with its 1/1 pot brakes, solid vented front rotors (about 240mm i think) and non-vented single piece rear rotors (like 220mm.. or less)

stops from 60-0 in 126 feet

wut wut?



brake pad selection is much more important than rotor size and or build

most cars already come with properly sized brakes anyway (except maybe the new Dodges), its the pads that are flunky.

but whatever, go bust coin on 250/piece rotors, i'm happy with my 60 dollar blanks, and if i lived close to you would love to come by and out-brake you, maybe then you'll get it.
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Old 04-14-2010, 07:49 AM   #12
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NW OBS,

I'll be glad to out brake you with my blank rotors. Heh.

Sorry but I do track days and autocross events, and I know the owners of a 24-hour Rolex Porsche Cup team... I know what I'm talking about.
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Old 04-14-2010, 10:41 AM   #13
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Because guess what... they are cars ready to go on the track and not meant to be daily drivers.
That is hysterical. Got a 2006 Carrera S in front of me (cabriolet) that is NOT a track car. It's a blvd cruisers that run down a canyon hard. 'Drilled Daily Driver'.

Partial List of DD Mercedes Benz with drilled rotors:
C Class 300 Sport (228hp of fire breathing track car?).
SLK 300 (2 dr blvd cruiser)
S Class 550 Sedan (there's a 5,000lb limo ready for the track)
E Class 350 Coupe (2 door 3800lb track star with 268hp)
Every AMG in the line up (12 of them)

I have sold 20 AMG's in the last two years and not ONE has seen track time... ALL daily drivers. My service manager who has serviced exclusively MBZ for the last 15 years says not a SINGLE incidence of disk failure due to 'drilled' rotors on our product.

Daily driver's FTW!

BTW, my response to you was responding to my children at risk cause I drive with cross drilled rotors. Which is shear and total nonsense!
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Old 04-14-2010, 10:46 AM   #14
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Originally Posted by Gooshin View Post
you know whats even more funny

a few minutes online gave me the 60-0 times for a SL550 Mercedes, it was 115 feet

a bone stock 2000 VW Golf, with its 1/1 pot brakes, solid vented front rotors (about 240mm i think) and non-vented single piece rear rotors (like 220mm.. or less)

stops from 60-0 in 126 feet
So let's see. A car that weighs 1200lbs more then the Jetta, stops 11 feet shorter then the Jetta???

What's your point?

That eleven feet just saved me and my kid's ass ~

My point was simply buy the best braking equipment you can afford ~ you will brake better then stock EVERY f'n time!
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Old 04-14-2010, 10:58 AM   #15
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Originally Posted by NW OBS View Post
So let's see. A car that weighs 1200lbs more then the Jetta, stops 11 feet shorter then the Jetta???

What's your point?

That eleven feet just saved me and my kid's ass ~

My point was simply buy the best braking equipment you can afford ~ you will brake better then stock EVERY f'n time!
my point is that i take that VW and upgrade the pads and i'll be stopping the same distance as a car that costs nearly six times more.

your flag waving for cross/drilled rotors is nothing than proof that marketing works if you think that a few holes in your rotors are responsible for all that mad stoping powa, when they are the least important bit in the entire construct.
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Old 04-14-2010, 11:01 AM   #16
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Originally Posted by NW OBS View Post
That is hysterical. Got a 2006 Carrera S in front of me (cabriolet) that is NOT a track car. It's a blvd cruisers that run down a canyon hard. 'Drilled Daily Driver'.

Partial List of DD Mercedes Benz with drilled rotors:
C Class 300 Sport (228hp of fire breathing track car?).
SLK 300 (2 dr blvd cruiser)
S Class 550 Sedan (there's a 5,000lb limo ready for the track)
E Class 350 Coupe (2 door 3800lb track star with 268hp)
Every AMG in the line up (12 of them)

I have sold 20 AMG's in the last two years and not ONE has seen track time... ALL daily drivers. My service manager who has serviced exclusively MBZ for the last 15 years says not a SINGLE incidence of disk failure due to 'drilled' rotors on our product.

Daily driver's FTW!

BTW, my response to you was responding to my children at risk cause I drive with cross drilled rotors. Which is shear and total nonsense!
Like I said before, those drilled rotors are for show on those cars.

More information since you don't understand this:

Quote:
Contrary to legend and automotive folklore, it is NOT true that holes drilled into rotors make a car stop faster. Neither does slotted rotors, for the most part.

Drilling holes in a rotor does four things:

1. Holes against brake pads have no friction, so you reduce the contact area of the brake pads. This means you have to push harder on the brakes to stop in the same distance, which means an increase in friction, and of course heat, which is what causes warped rotors.
2. Drilling reduces the thermal mass of the rotor, increasing the heat gain at a rate higher than the rate of heat loss by air conduction. It also reduces the rate of heat loss wicked out the spindle and frame. Cross drilled rotors actually run hotter if all other factors are equal.
3. It encourages warping, not only by running hotter, but because the rotor contains less and --more importantly-- uneven mass, the rotor heats up unevenly and at a higher temperature, creating stresses it wouldn't have otherwise.
4. Drilled rotors, due to these above mentioned stresses are prone to "connect the dots" stress fractures. Once one crack occurs, stresses reroute around the crack and put more stress on the remain intact areas. Oh, and when you subject a medium to stress, it heats up, it warps, and it cracks even easier.

There is a benefit to cross drilling rotors. If you don't need a lot of stopping power, but you want to get up to speed in a hurry, drilled rotors are the ticket. You shave weight from rotating mass which is worth it's weight in gold (or worth it's weight in horsepower), and of course, they look badass in those 5-spoke wheels.

So if you are working on a speedway-only drag racer, cross drilled is fine.
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More facts about rotors. May the great myth of drilling rotors for improved cooling finally die...

Darrick Dong; Director of Motorsports at Performance Friction.

"In the days of asbestos pads there was a gas boundary layer that appeared at the interface area of the pad and rotor. Although that gas boundary layer still occurs it is much less of a problem with modern friction materials. Slots are more than adequate to carry that gas away. Years ago that gas boundary, along with reducing weight, led to the popularity of drilled rotors. However, in the intervening period, the myth has persisted that cooling is the main reason for drilled rotors. Anyone that tells you that drilling makes the disc run cooler is smoking crack."

Why is Dong so adamant? Because he works with racing brake systems for a living and it isn't too hard to take two identical rotors, drill one of them and slot the other, put them on a brake dyno and measure temps and life.
So, do you smoke crack? Haha.

Seriously though, I think you got brainwashed
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Old 04-14-2010, 11:06 AM   #17
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my point is that i take that VW and upgrade the pads and i'll be stopping the same distance as a car that costs nearly six times more.
If they had not upgraded every single component of the braking system from master cylinder, booster, lines, calipers, disc and hats that car that weighs 1200 lbs more then the Jetta (and capable of over 150 mph) wouldn't stand a chance to beating the Jetta!

EVERYTHING must work in harmony. When you touch one item you need to breath on all others to keep a balanced system. Perhaps you should read my initial post again? The drilled rotors were only one step in the process to better braking.

No, I don't believe my cross drilled are responsible for my 'mad breaking performance'... just one of the 5 components I chose to upgrade.

I'm done, nice chatting with ya both ~
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Old 04-14-2010, 11:12 AM   #18
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No, I don't believe my cross drilled are responsible for my 'mad breaking performance'... just one of the 5 components I chose to upgrade.

I'm done, nice chatting with ya both ~
Once again, drilled rotors are for weight loss and looks. That is it. To basically kill the rest of the arguement, here is even more information to prove you are wrong. Perhaps you will ensure your family's future by switching to blank rotors very soon.

Judge, I rest my case.

------------------

Darrick Dong; Director of Motorsports at Performance Friction: "Anyone that tells you that drilling makes the disc run cooler is smoking crack."

Power Slot: "At one time the conventional wisdom in racing circles was to cross-drill brake rotors to aid cooling and eliminate the gas emitted by brake pads. However, today’s elite teams in open wheel, Indy and Trans Am racing are moving away from crack prone, cross-drilled brake rotors in favor of rotors modified with a fatigue resistant slotting process."

Stop Tech: "StopTech provides rotors slotted, drilled or plain. For most performance applications slotted is the preferred choice. Slotting helps wipe away debris from between the pad and rotor as well as increasing the "bite" characteristics of the pad. A drilled rotor provides the same type of benefit, but is more susceptible to cracking under severe usage. Many customers prefer the look of a drilled rotor and for street and occasional light duty track use they will work fine. For more severe applications, we recommend slotted rotors." (Note that even though Stop Tech sells both drilled and slotted rotors they do not recommend drilled rotors for severe applications.)

Wilwood: "Q: Why are some rotors drilled or slotted?
A: Rotors are drilled to reduce rotating weight, an issue near and dear to racers searching for ways to minimize unsprung weight. Drilling diminishes a rotor's durability and cooling capacity."

From Waren Gilliand: (Warren Gilliland is a well-known brake engineer in the racing industry and has more than 32 years experience in custom designing brake systems ...he became the main source for improving the brake systems on a variety of different race vehicles from midgets to Nascar Winston Cup cars.) "If you cross drill one of these vented rotors, you are creating a stress riser that will encourage the rotor to crack right through the hole. Many of the rotors available in the aftermarket are nothing more than inexpensive offshore manufactured stock replacement rotors, cross drilled to appeal to the performance market. They are not performance rotors and will have a corresponding high failure rate"

From Baer: "What are the benefits to Crossdrilling, Slotting, and Zinc-Washing my rotors?
In years past, crossdrilling and/or Slotting the rotor for racing purposes was beneficial by providing a way to expel the gasses created when the bonding agents employed to manufacture the pads...However, with today’s race pad technology, ‘outgassing’ is no longer much of a concern...Slotted surfaces are what Baer recommends for track only use. Slotted only rotors are offered as an option for any of Baer’s offerings."

Grassroots Motorsports: "Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled because early brake pad materials gave off gasses when heated to racing temperatures, a process known as "gassing out." ...It was an effective solution, but today's friction materials do not exhibit the some gassing out phenomenon as the early pads. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it...Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)

AP Racing: "Grooves improve 'cleaning' of the pad surfaces and result in a more consistent brake performance. Grooved discs have a longer life than cross-drilled discs."

also from AP: "Cross drilled...can compromise disc life. Radiused drilled...mainly used for aesthetic reasons on road applications."
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Old 04-14-2010, 11:28 AM   #19
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Like I said before, those drilled rotors are for show on those cars.
So if they're only on there for looks, does that mean they're not really drilled? Because i'm quite sure they are drilled all the way through, and whether they're there for looks or not if your theory is right then NW OBS is also right in saying that according to your theory many of the daily driver built high end vehicles with drilled rotors are also unsafe.

And I'm pretty sure he doesn't put his on for looks, to be what'd you say "bling blingin" ? or just because he saw an add for them. I doubt he changes his every week, because the "strainous" daily driving routine doesn't put as much pressure, heat, and/or strain on the rotor as much as a track car does. Which is why they change them every race. I'm pretty sure his drive to the grocery store won't cause him to need to change his rotors when he gets back... Not sure why you're so against one person using slotted rotors on his DD, he has substantial and physical proof that it has helped him, how do you argue against that? No you actually did crash you're just brainwashed?

It's pretty low to call out a father by telling him he's a risk to his own kids man, not cool.
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Old 04-14-2010, 11:33 AM   #20
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So if they're only on there for looks, does that mean they're not really drilled? Because i'm quite sure they are drilled all the way through, and whether they're there for looks or not if your theory is right then NW OBS is also right in saying that according to your theory many of the daily driver built high end vehicles with drilled rotors are also unsafe.

And I'm pretty sure he doesn't put his on for looks, to be what'd you say "bling blingin" ? or just because he saw an add for them. I doubt he changes his every week, because the "strainous" daily driving routine doesn't put as much pressure, heat, and/or strain on the rotor as much as a track car does. Which is why they change them every race. I'm pretty sure his drive to the grocery store won't cause him to need to change his rotors when he gets back... Not sure why you're so against one person using slotted rotors on his DD, he has substantial and physical proof that it has helped him, how do you argue against that? No you actually did crash you're just brainwashed?

It's pretty low to call out a father by telling him he's a risk to his own kids man, not cool.

actualy, this all started when i stated:

Quote:
Originally Posted by gooshin
do not bother with fancy rotors, the stopping power is all the in the brake pads.
NW OBS has an issue with my statement, and brings up the following main points up for discussion,

that, apparently, my roster of racer friends is far inferior to his, and i guess all of them are as loony as I am.

However by doing so he first and foremost alludes to a discussion of motorsports.. now we are getting confused

Quote:
Originally Posted by NW OBS
What do you know that every single race team (amateur or professional) do not???
In fact i even asked for a clarification from him; what is it exactly that he wishes to discuss, the motorsport aspect or the daily driver aspect of fancy rotors?



then he made the academic claim that slotted + drilled rotors in fact dissipate heat faster, which as noTe has been trying to indicate, is not a fact at all.

Quote:
Originally Posted by NW OBS
Slotted, drill rotors dissipate heat faster and more effectively. Heat = fade, fade equals crash.
The rest is a direct result of the above two comments.

Yeah...

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