[mkaaes]

This has probably been covered but it's hard if not impossible to search the thread on the iPhone app. I plan to do light tracking and will obviously be upgrading the brake-lines as well as pads. My rotors are about due to be replaced, should I go with slotted or drilled?

[SV Concepts III]

On a street car, there is not much of a performance benefit to either. Choose whichever you think looks better

[DV]

Drilled rotors can develop heat cracks between the holes. I'd go slotted.

[Brooklyn e70]

Originally Posted by DV

Drilled rotors can develop heat cracks between the holes. I'd go slotted.

^^agree x2

[mkaaes]

Looking at the M3 brakes they're drilled, I wonder how they hold up

[Eric@e2design]

If you're after performance:

If you're not fading then NEITHER, if you're fading and still on stock pads try going one up on pad temp..
If you're still fading after that then DOT4 and post back here.

Questions to ask yourself:
What type of pads/rotors am I running? Consider going OEM or if BMW Performance makes a set.

If you're going for looks..
Doesnt matter lol

[fdriller9]

On a street car....slotted and drilled will serve little purpose.

They can help in rain to shed water away from the pads/rotors and they can help remove pad material...keep it fresh, prevent glazing.

But it will do little thermal wise in allowing heat to dissipate.\

And drilled rotors will not crack under normal driving.....

[Eric@e2design]

Originally Posted by *********

On a street car....slotted and drilled will serve little purpose.

They can help in rain to shed water away from the pads/rotors and they can help remove pad material...keep it fresh, prevent glazing.

But it will do little thermal wise in allowing heat to dissipate.\

And drilled rotors will not crack under normal driving.....

Negative.. your pads are always in contact with your rotors and that sheds water away for no "lag" during wet conditions. Stopping distance is increased mainly because of traction not because your brakes ever need to shed water away.

Another NO our caramic and metal brake pads (except maybe like the $10 pads made with asbestos in mexico or something lol) do not produce gasses when heated.

[AWD Addict]

Originally Posted by Nick@Jlevi SW

On a street car, there is not much of a performance benefit to either. Choose whichever you think looks better

If you're running garbage replacement pads or go to the track a lot, the slotted will help prevent glazing/ brake fade.

Drilled are a waste. Cracking can also happen, though I've only actually seen it first hand once.

[AlanAZ]

Consider EBC "dash" slotted rotors. Most of the benefits of a standard slotted rotor, without the whirring sound under some braking situations. Plus they're made in the UK, and not China/Taiwan, with better QC.

http://www.ebcbrakes.com/automotive/...d_rotors.shtml

[Alpina_B3_Lux]

Originally Posted by Eric@e2design

Negative.. your pads are always in contact with your rotors and that sheds water away for no "lag" during wet conditions. Stopping distance is increased mainly because of traction not because your brakes ever need to shed water away.

That is somewhat misleading.

A well-known problem of the E9x and also of the E46 before that was that the bigger brake discs (6 cylinder engines) had a tendency to get a water film on them, which resulted in erratic braking behaviour e.g. delayed braking response or veering to one side. I also experienced that first-hand in my previous car (E46 Alpina B3, it had the 330i brakes) as well as with my current 335i (in spite of the fact that the 335i is supposed to have an automatic water-film elimination procedure during driving). After having driven for a longer period of time under very rainy conditions, the braking response was severely delayed and came only fully after 1-2 seconds; sometimes the car also veered to one side although I was driving straight.

Slotted, dimpled or drilled rotors are much better at preventing the build-up of a water film on the brake disc and therefore improving braking response in the wet over a plain brake disc.

For me that's the only advantage - but it's a substantial one IMO that is quite important for safe daily driving. Which is why I changed my brake discs very quickly after acquiring my current car.

Alpina_B3_Lux

[farbmw]

Originally Posted by Alpina_B3_Lux

That is somewhat misleading.

A well-known problem of the E9x and also of the E46 before that was that the bigger brake discs (6 cylinder engines) had a tendency to get a water film on them, which resulted in erratic braking behaviour e.g. delayed braking response or veering to one side. I also experienced that first-hand in my previous car (E46 Alpina B3, it had the 330i brakes) as well as with my current 335i (in spite of the fact that the 335i is supposed to have an automatic water-film elimination procedure during driving). After having driven for a longer period of time under very rainy conditions, the braking response was severely delayed and came only fully after 1-2 seconds; sometimes the car also veered to one side although I was driving straight.

Slotted, dimpled or drilled rotors are much better at preventing the build-up of a water film on the brake disc and therefore improving braking response in the wet over a plain brake disc.

For me that's the only advantage - but it's a substantial one IMO that is quite important for safe daily driving. Which is why I changed my brake discs very quickly after acquiring my current car.

Alpina_B3_Lux

Interesting, so what kind of brake system you suggest? Because they are saying we are going to have a very wet summer this year in Canada.

[Alpina_B3_Lux]

Originally Posted by farbmw

Interesting, so what kind of brake system you suggest? Because they are saying we are going to have a very wet summer this year in Canada.

Replacing the OEM brake discs with slotted, dimpled or drilled aftermarket discs will help a lot. That's what I did (see above).

I'm running EBC Turbo Groove slotted + dimpled, but in particular in the US there are a number of alternatives, the best being probably (short of a BBK) the new two piece rotors that Mr. 5 reviewed some time ago (available at HPAutowerks).

Alpina_B3_Lux

[farbmw]

Originally Posted by Alpina_B3_Lux

Replacing the OEM brake discs with slotted, dimpled or drilled aftermarket discs will help a lot. That's what I did (see above).

I'm running EBC Turbo Groove slotted + dimpled, but in particular in the US there are a number of alternatives, the best being probably (short of a BBK) the new two piece rotors that Mr. 5 reviewed some time ago (available at HPAutowerks).

Alpina_B3_Lux

Cool thanks!

[JoosyJoos]

I'd go with whatever you think looks better honestly. The chance of you ever cracking a rotor (due to it being cross drilled) is exceptionally rare and you'd have to be one heck of a driver to do it probably.

[AWD Addict]

Originally Posted by JoosyJoos

I'd go with whatever you think looks better honestly. The chance of you ever cracking a rotor (due to it being cross drilled) is exceptionally rare and you'd have to be one heck of a driver to do it probably.

That's probably fair. though I'd also warn against drilled rotors on a street car though to avoid the boi racer look.

[fdriller9]

You also want to keep in mind that slotted, drilled, dimpled, or any combination of these will eat through pad material slightly faster.

[Projekt_BooGie]

I was told that the rotors that crack the most were the ones that a were not suppose to be drilled (blank rotors) and a manufacture (like some on ebay) would buy like brembo blanks and drill holes into the rotors themselves.

I've never track any of my cars but I know a few people who have, and they upgraded rotors/pads/brake lines and they love it for track use. I've actually knew 2 guys who had bbk and took them off to go back to there normal rotors/pads/upgrade brake lines. They said it felt better??