Here's a bite-sized course on the effectiveness of brake rotors, which compares the relative merits of drilled, slotted, and vented rotors.

Read the rest on the MBWorld homepage. >>

 

In general, he's correct.

A few minor points:
Slotted rotors are used in professional racing because:
1) There's a chance that another car will "puke it's guts" (water, oil) on the track. Then, the driver will drive with the brakes on lightly to dry off, and clean off, the rotor and pad.

2) The slots are aggressive and cut a non trivial amount of the pad away. This allows for the driver to keep the pad surface clean from pits and potential glazing (glazing isn't that common any more).



As for drilled rotors:
The head of the Corvette platform put it the best when the Corvette came with drilled rotors from the factory for the first time. He "basically" said that the street braking performance was minimally, if at all, effected.

In other words, on real life roads, with real life conditions, the brakes were so over-sized, that braking while driving the legal limit of 55mph would not be effected at all by the reduction of braking ability caused by the addition of the holes.

In other words, iirc, the brakes didn't hit their braking ability until ~70MPH. So, big deal if the rotors had holes - they made the rotor look nice!

If someone wanted a real track rotor for the Corvette, then buy one!
Imho, anyone that takes their car to a track and complains about having to buy and replace the rotor, really needs to get their head checked. Tracking a car requires regular, often after every session, brake fluid changes. It also requires careful checking of pads, rotors, and calipers.
Also, the ABS pump that can last 30+ years on a street car, will be lucky to go a whole season of track racing. So, count on replacing the ABS pump at least once a year.


So...., will *I* go with the C32 AMG MB OEM rotor with holes (I have them) when I do my brake upgrade to my 2005 C230K?
Or, will I go with solid rotors?

Hmm, I'll have 4-piston calipers, 13.6" rotors, and Hawk HPS pads (*I* rather have dust and great pads, verses no dust and okay pads). Also, I'm stuck with either a 225 or 245 width front tire on my 2005 C230K :-P.
So, I am semi-leaning towards the OEM drilled rotors.
Imho, even with summer-only ultra-performance tires, I don't see the front brakes being a limiting factor until ~70-80mph. Imho, the width of my front tires will be the more limiting factor for braking performance. And, that's assuming a perfect road in perfect shape on a perfect day. Imho, in New England, don't even think of betting on that.
So, again, I don't see having the OEM drilled rotors being a disadvantage in the braking performance in normal legal street driving in the USA in New England.

Fwiw, there are some ***** drilled rotors. Too many holes. Poor venting. Poor material. Poor tolerances. And, so on.
So, for the nth-hundred time , I'm talking specifically about the from the factory C32 AMG OEM drilled rotors.

I hope the above helps people.