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Discussion Starter #1
If they are so bad why are they installed from the factory on higher end cars?

Someone had a link where they ordered the slotted rotors & brakes, what site was that?
 

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mobiless2
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Factory cars like AMG, Porsche, etc the holes are cast into the mold. Aftermarket rotors are drilled, that is why they always crack around the drilled hole area.

EBC makes dimpled & slotted.

One of our sponsor. http://throwdownperformance.com/
 

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Moderator
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I've said it before here, and I'll say it again.

I worked for a startup that was making prototype brake rotors for an American auto company for their flagship two-seat sports car, both names you would immediately recognize. The drawings called for something like 52 1/4" through-thickness holes in each rotor. If you had to drill that many holes through 1.25" thick reinforced silicon carbide, you'd want to know why, too.

So we asked. We asked their lead brake engineer assigned to the project. Why were the holes there?

"Aesthetics," he said. "The only reason they're there is because they look cool."

I'm not saying that's the only reason. Search my posts and you'll find calculations that show holes can reduce the "air hockey puck" effect caused by oiffgassing of pads. But 99% of drivers won't need that under 99% of driving conditions, even in exoticars.
 

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The new mclaren mp4-12c, when purchased with a steel brake option, has no drilled holes or slots.

It uses a blank rotor
 

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I've got them, the next time I need to change the brakes/rotors I'll put high quality blanks on it. They look nice but I dont think they serve any functional purpose. I noticed after they were changed that braking was louder then it was before, I usually only notice when I am hard braking but even coming off the highway its noticable in the cabin. Stick with aftermarket blanks like Brembo or Stoptech.
 

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Spirited Cruiser
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I had the same question as the OP when I was researching for my brake up-grade following two hairy incidents.

After a lot of reading I chose to go for the drilled and slotted for two reasons.
1. Better heat dissipation
2. Aesthetics

I live in a country where summer lasts for nearly 8 months of the year, with temperatures sometimes as high as 132 °F. The blanks dissipate heat slower, this made the brake fluid boil earlier causing brake-fade in a very short time.

The drilled-slotted rotors fixed this issue. Although, I must add that I also replaced my brake pads with ceramic ones (Posi-Quiet) and changed my brake-fluid to Castrol SRF (liquid gold ;)).

What is also important to note - as you may read on a number of threads, is the construction of the rotors with regards to the drilled holes and slots. Improperly designed rotors will just cause more misery!
Therefore, I also did some reading on the designs chosen by different manufacturers for their rotors. I was most impressed by StopTech, which I eventually ended up buying.

StopTech uses top-quality blanks to manufacture their rotors. Every design is tested before being put in service. The after-sales service is top-notch. Just to be clear, I'm not connected to StopTech professionally. I'm just a very satisfied customer.

I've heard mixed opinions about EBC's. One may have to compare their design with StopTech's to decide.

I'm guessing that the OP would have already made the decision about the rotors. We would like to hear about it....
 

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If I had the money upgrade to carbon ceramic brakes... it works even better with heat.
 

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Spirited Cruiser
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+1 for the Carbon Ceramics. I read some time back that StopTech was developing these as well. How far they have gotten, I don't know.

With regards to the performance (heat dissipation) of the drilled-slotted rotors on my car, I checked the temperatures on them after different driving stints and different weather conditions using a 'temperature detector'. I have only come back impressed. They perform remarkably well.
 
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