1loveaudi

Do drilled rotors feel different when you stop than non drilled or oem? Is there an actual performance gain or is it mostly aesthetic? I have driven an Acura with drilled and slotted rotors and felt a slight vibration when stopping. I don't want to have that in my Audi if I decide to change.

Fahrer

I have drilled rotors on my 911. They are very smooth when stopping. They are not for show. The holes provide added ventilation for cooling and provide an outlet for any gassing that can occur under severe braking to reduce fade. Folks who track their cars can eventually see cracks developing around the holes. Some of those folks change over to slotted rotors. Vibration is likely a result of warped rotors or detective pads.

gk1

Not apples to apples, but I tried slotted rotors once. They made noise which I didn't care for so I never really considered anything but plain ever again.
Also drilled allowing for venting of pad gasses is old school for very old pad materials...not really an issue any more...it is primarily aesthetic...maybe a very slight weight decrease.

tjf

Yes, Slotted will give you noise, maybe a bit of pulsation. I've never tried drilled, but have heard they are subject to cracking.

1loveaudi

Thanks for the input guys

Fahrer

Cracking with drilled rotors is something that can happen mainly with cars that are tracked. Drilled rotors perform better in wet conditions as the steam created between the pads and rotor is dissipated more quickly. It is definitely not done to reduce weight as an insignificant amount of metal is removed. I am sure some car brands or after market rotors use drilled holes as an appearance item just like useless rear wings, fake air scoops, decals, stripes, fog lights, etc.

Vodka G

....drilled are for show

Since asbestos based brake pads were outlawed in the nineties, new materials and bonding adhesives have been developed. The now common ceramic based pads do not produce the outgassing problem in any conceivable street use, so there is no real function-based reason to use drilled rotors. Slotted rotors may still be useful in their ability to remove pad glazing but consequently produce faster pad wear. That spells more brake dust on your wheels, which can be corrosive to aluminum wheels, as are many of the chemical cleaners used to remove that dust. Since most hot rods are not driven hard enough to get hot enough to glaze the pads, slotted rotors may offer little in the way of better brake function.