Front disc and pad options.??

[BigDave]

Has anybody fitted some drilled / grooved discs, and performance pads to the front of their M40i.
If so, what make did you go for, and where did you get them from.?
Also did they make a difference at higher temps.
Thanks..

[q96169we]

Have always been using BMW original pads and discs as bmw warranty gave me a brand new set every 3-5k miles so no need to spend my own cash. Based on my experience (10+ trackday so far), they are pretty good at high temp. Still give you strong brake power after 15+ continuous laps on, for example, Silverstone GP circuit. The pedal felt soft at high temp, but if you are after firm pedal feel, change brake line and fluid first.

To me, the biggest issue is that after extreme high team on track, if I don't use the brake very hard on road, the disc will distorte gradually causing vibration when brake gently. Hence the warranty gives me new disc and pad as they failed BMW's test and it's still within 12month/12k miles bmw part warranty period.

[BigDave]

Interesting. Thanks for the update....

Regarding the road use , is it the disc distorting or the pads that have gone off, as pads can degrade after hard track use, and leave pad build up on the disc....

Does anybody know if there is an aftermarket pad , ie Performance Friction or other,, preferably not Green / Red stuff pads...

[q96169we]

My understand is that the pad dust build up on disc which under high temperature will turn into a kind of coating. This coating is very hard so that it can actually protect the underlying metal disc from wear and consume the pad instead. However, this coating can detach from the disc surface piece by piece as it's mechanical bonded not chemical bonded. Consequently, the disc surface with this coating will wear slower than the area without this, which ultimately leads to uneven wear on the disc. To preserve (or to strip) the coating, I was told I should use the brake harder so that either the coating will be replenished, or it will be stripped more evenly before uneven wear starts to take place. I've been experimenting with this idea with the current set, and it survives much longer than previous disc (3 trackdays and thousands of miles on road so far), whereas previous sets usually failed BMW's test after one trackday and 1-2k mile on road.

Going forward as the car will soon out of warranty, I am thinking about trying yellow stuff with grooved disc (mainly to clear the brake pad dust from the surface, instead of improving cooling etc.). Drilled disc prone to crack and it won't offer much more (well, maybe slightly better ventilation, and slightly lighter) than grooved disc so I try to avoid them for now.

[BigDave]

Thats a great explanation of the problem, and one I have experienced, [on other cars], to the point of having the discs skimmed to remove the build up / warping...

Which is why I asked my initial question, and why I am contemplating the grooved discs aswell.

[q96169we]

To be fair, if you will make the brake system that hot, you must consume disc and pad pretty quickly. At least this is my assumption. In this case, I think you can try different brand of pad and/or disc to see which one give you better confidence, as even if you don't like certain combination, they will wear out quite quickly so that you can try the next combination. This is what I plan to do next starting with EBC yellow and their grooved disc.

[brillomaster]

are you wanting to do any track work, or are you just after a fast road setup?

EBCs are fine for road use, but won't last long if you're doing full trackdays.

[q96169we]

Haven't tried any EBC stuffs yet if i'm honest. Also, when you say full trackday, do you mean full day on track continuously like endurance race? or like 30min section with some cool down/break time? My OEM pad and disc has been okay so far for full day trackday but 30min on track then 10-30min cool down break then back on track... Maybe I'm a still not driving fast enough? Also, do you have any recommendation since I will need to look into this topic seriously.