yourk

I think like it for the look. Performance Wise, aren't slotted rotters the best anyways?

Jretal

I've had x-drilled brembos on my car for 40-50k with many track and autox events on them and didn't have a wink of an issue. Rotors show no signs what so ever of cracking or anything.

A lot of the failures you see are with zimmerman rotors, and the main reason that happens is because zimmerman rotors are seconds. What I mean by that is that they had a flaw (such as a garment you get from an outlet store) that won't allow it to be used as a "high end" product, but can still be sold at a lesser price.

Jretal

it is used to create more leverage, enabling the brakes to exert more force to stop the car. A larger rotor will move the caliper further from the center of rotation (the axle) which will create a bigger lever arm allowing the caliper to exert more force, resulting in faster stopping.

For the most part, it is because of that more than the heat dissipation, at least in my mind.

You are right that it would take longer to head up an item with more mass, but at the same time, the lighter mass obj will take less time to shed the heat... that kinda deal. It's a tradeoff basically. If I actually remembered all the thermodynamics stuff I did in school I'd be able to give you real values as to why this was the case, but alas that is one of my many ME classes I pushed out of my mind =P

The x-drills were originally said for cooling and helping to clean off the pads. Unfortunately, as you use the rotors, the holes fill with brake dust, essentially blocking off these cooling ports.

I like 'em for the look personally, but there is *some* functionality. They do help clean the glazing off the pads after a track event faster (when compared to my dad's SVT with stock smooth rotors which took a LOT longer), but not nearly as agressivly/quickly as slotted rotors.

leosphere

I doubt the pad is being shaved, not on'y b/c of my experiences with them but also b/c if you look at the surface of the pad in relation to the surface of the rotor, you will notice that no part of the pad gets lower than the surface of the rotor. Its alway in contact with a larger part of the rotor surface, even when the pads are over the holes. For it to get shaved off, it would need to go lower than the rotor surface. If that makes sense, its just a thought. I'm not an expert, its just how I see it.

monsterness

you're thinking of this as a two step process - it heats up, then it cools down... but, as with the computer, it tends to be a continuous process. A little bit of braking adds some thermal energy and a little bit of airflow sheds some heat. Brake a little more often or harder, and you'll generate thermal energy faster, when you accelerate again (unless you're on a hill, you can't continously brake without eventually stopping) you'll shed that heat. The point is that the cross drills add more ability to shed heat then they detract from the ability to hold heat (from losing mass). Same thing with the finned CPU block - it has many times more surface area then a solid block, but only a few percent less mass.

and warping isn't an effect of cooling/heating quickly, its an effect of doing it unevenly. Well-made cross drilled rotors should be less likely to warp, as they can shed heat more evenly because some of the interior surfaces are exposed. Warping occurs when you quickly cool the outer portion, causing it to shrink, while the inner portions are still hot.

Finally, andy_fl pointed out the weight savings, which, even if its only a few pounds, is pretty significant for your acceleration because of the rotational inertia involved.

all of what I'm saying is theoretical, as I don't have a lot of practical experience with how well these things work, just pointing out the theoretical engineering behind this.
-rich

BSK

lol. ACHTUNG

gh0st

I know the possibilty of them snapping in half isn't all that likely but its another thing to think about

platrin

your drilled holes of brake dust every few days...would you?

WJM

*whimper* Noobs...i cant read anymore....

Jretal

but that's neither here nor there