Originally Posted by r-americagroup
That's factually incorrect. Drilled or slotted rotors do provide more bite in addition to other significant advantages. Manufacturers of the rotors and the SAE have a plethora of statistical evidence and it makes for some really good reading.
However, I do realize that this is your thread and I don't wish to muddy it up.
I'll rephrase my statement a bit, see if we can come closer to the middle somewhere.
Drills and slots to have theoretical and performance advantages.
- weight savings
- more airflow for better cooling
- more surface area for better heat dissipation
- broken surface allows off-gas and dust to evacuate (the only possible avenue I could see bite increasing at all, but minimally if at all)
This is true.
However the benefits are not likely in any practical way to translate to a street car, or even a race car driven on the street. The entire package needs to work together anyway. In my experience, to justify the need for these features one would need to be pushing some really high end pads and then seeing a need for additional cooling or degassing. Even then not all drilled rotors are the same. Most that you see for sale are plain rotors with holes in them, where the drill pattern is not strategically placed or done with specialized equipment, making the holes good places for cracks to start than anything else.
On the street the weight advantage is not going to amount to much improvement without a serious diet on the whole car. Any cooling advantage will be moot since sufficient heat will not be built up, and, if it is, the pads will go off long before the rotors will provide a cure. Even the dust/gas evacuation is not really something I have seen be THAT advantageous.
So yes, improvements can be made when an entire package works together, but simply changing plain rotors for slotted and/or drilled ones is going to get more looks than performance advantage. Even if you believe the stock rotors warp too easy, I challenge this with the pads being the root cause anyway. Brakes and their impact on your driving ability is mostly in the pads.