4g4me

I have read a few posts per day on the arguements between the slotted/drilled crew and the owners of stock replacement blank rotors....

This topic needs no replies recommending upgrades to bigger ANYTHING, but only to settle blunt arguements. Please comment with personal 1st hand opinions, no "he said she said bullshit"

this is an article that I found on the internet, temple of vtec.....FYI
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Cross Drilled Rotors

Cross-drilled rotors do actually run hotter by 2-3%. The benefit of the rotors is to allow the pads to vent the gasses made under extreme use. For street use there is little or no benefit. For auto-x tracks with hard braking corners they can help some. Auto-x is usually a little slow for the cross-drilled rotors to become effective. A track course with a 100mph to 20mph corner would yield a significant difference. I've had the cross-drilled rotors and metal master pads for about 20,000 miles with no side effects. I can't tell that the pads would be wearing faster.

Because of the lower mass of the drilled rotors they will heat up faster and to higher temperature than the non-drilled rotors. Consequently you'll want to put in some better fluid and/or cooling ducts. I use Motul DOT 3 synthetic brake fluid. It's a bright blue color. The only probably with performance brake fluid is they usually boil at really low "wet" temp. For example after 2 years when you're braking system has absorbed all the moisture from the air the fluid will boil pretty quickly. The Motul DOT 3 Synthetic boils at 300c (572 f) dry and 148c (298 F) "wet". As you can see the wet boiling point is less than half of the dry boiling point. No big deal just make sure you bleed your brakes at least once a year. You racers out there would want to do it after every event. And make sure there is NO air bubbles in the system.
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So anyone else want to share information? And I dont care what porche or ferrari puts on theis cars.....I care about facts....

gtpilot

I have run cross drilled and slotted rotors on my racecar...the cross drilled were more prone to cracking and distorting than a stock one. All of the cracks would start at one of the wholes we had drilled in the rotor - we tried a lot of different techniques to resolve the problem - chamfering/radiusing the holes by machining, pressing a large hardened sphere into the hole to work work-harden the edge, cryo treating the rotors...but they would always crack eventually. The provided excellent braking performance, even in the wet. I would typically use three sets of rotors to one set of pads - Porterfield R4 Carbon/Kevlar.

Then we tried slotting the rotors...no more cracking problems and it is vastly cheaper to do. Wet braking performance is great and I can not tell the difference in effective braking power vs. cross drilled. The best part is that I only change the rotors every time I change pads now - I could continue to use the rotors, but on a racecar I would rather cycle out parts than be sorry.

Kirk

kommon_sense

As you stated in your post, cross-drilled have significantly less surface area on the rotor than blanks. Slotted rotors also have less surface area than blanks. For regular street applications, this reduce surface area results in reduced braking ability. Pad gassing isn't as big a problem as it used to be so slotted and/or cross drilled will not provide any benefit.

With that said, I have slotted rotors on the rear and brembo blanks on the front. I had slotted on the front as well, but they warped. So I decided to save some money and replace them with brembo blanks. My braking with the blanks is noticeably better than it was with the slotted. However I am contributing this to the fact that the slotted rotors were warped. In my own limited experience, the blanks brake every bit as good as slotted rotors when used in street applications.

4g4me

hopefully we can sum up all the questions that peole are having about the price vs. outcome with the slotted/drilled/blanks.

good information