New Rotors

[p66]

Anyone know of or using a replacement rotor that outperforms OEM on the track?

[mlhj83]

A quick search would have given an answer. Performance Friction is the most popular one, but to be honest there aren't any discs on the market - in OEM dimensions - that is going to significantly outperform the OEM one, as the OEM one is pretty darn good. They are able to take a pretty good amount of abuse with the right pads, and the oem floating system is brilliant at allowing thermal expansion without the typical drawbacks of floating bobbins.

If you need a better brake setup despite using appropriate pads and oem discs, then you need an aftermarket brake kit from any of the reputable companies.

[p66]

Thanks

[edwinm3]

OEM

[M3PO]

Originally Posted by mlhj83

A quick search would have given an answer. Performance Friction is the most popular one, but to be honest there aren't any discs on the market - in OEM dimensions - that is going to significantly outperform the OEM one, as the OEM one is pretty darn good. They are able to take a pretty good amount of abuse with the right pads, and the oem floating system is brilliant at allowing thermal expansion without the typical drawbacks of floating bobbins.

If you need a better brake setup despite using appropriate pads and oem discs, then you need an aftermarket brake kit from any of the reputable companies.

I just went to the track for the first time with Project Mu Club Racer pads and Castrol SRF. After 10-12 minutes, the brakes would start to vibrate. A few easier laps would reduce the problem and they were perfectly fine for the next session. I am overheating the rotors correct? The thermal expansion is creating temporary axial runout in the rotors?

No pad transfer on the rotors...

[bigjae1976]

Did you bed in the pads before doing hot laps?

[mlhj83]

Originally Posted by M3PO

I just went to the track for the first time with Project Mu Club Racer pads and Castrol SRF. After 10-12 minutes, the brakes would start to vibrate. A few easier laps would reduce the problem and they were perfectly fine for the next session. I am overheating the rotors correct? The thermal expansion is creating temporary axial runout in the rotors?

No pad transfer on the rotors...

I use BMW M Sport pads and I've driven them to the point of absolute fade and have never had vibration under braking. I did however have significant vibration under braking when I tried the standard pads on track, which gradually disappeared (2 weeks after track day) as the uneven pad transfer wore off.

I'm inclined to think that yours is also due to uneven pad transfer. It's not something you can easily see. I'm fairly certain that most pads would overheat way before the OEM discs go beyond its maximum operating temperature. Also, once a disc is truly warped - not with axial runout due to pad deposits - it'll never recover, so by the fact that it gets better as you manage the brakes before the next session, points more towards uneven pad transfer.

[M3PO]

Originally Posted by mlhj83

I use BMW M Sport pads and I've driven them to the point of absolute fade and have never had vibration under braking. I did however have significant vibration under braking when I tried the standard pads on track, which gradually disappeared (2 weeks after track day) as the uneven pad transfer wore off.

I'm inclined to think that yours is also due to uneven pad transfer. It's not something you can easily see. I'm fairly certain that most pads would overheat way before the OEM discs go beyond its maximum operating temperature. Also, once a disc is truly warped - not with axial runout due to pad deposits - it'll never recover, so by the fact that it gets better as you manage the brakes before the next session, points more towards uneven pad transfer.

So if I follow you, you think I was over heating the pads, getting some uneven transfer, and then the easier laps were removing it?

[mlhj83]

Originally Posted by M3PO

So if I follow you, you think I was over heating the pads, getting some uneven transfer, and then the easier laps were removing it?

Yes. Just be aware that uneven pad transfer can become permanent if you keep hammering the brakes, as the parts of the disc with pad deposits get hotter and hotter with each pass of the brake pad; more so than the parts of the disc with no deposits.

OEM pads take some time to scrub off deposits because the pads are generally quite soft and not very abrasive. Also, in general, pads are at their most abrasive when cold to slightly warm temperatures.

[Chagrin]

Originally Posted by mlhj83

I use BMW M Sport pads and I've driven them to the point of absolute fade and have never had vibration under braking. I did however have significant vibration under braking when I tried the standard pads on track, which gradually disappeared (2 weeks after track day) as the uneven pad transfer wore off.

I'm inclined to think that yours is also due to uneven pad transfer. It's not something you can easily see. I'm fairly certain that most pads would overheat way before the OEM discs go beyond its maximum operating temperature. Also, once a disc is truly warped - not with axial runout due to pad deposits - it'll never recover, so by the fact that it gets better as you manage the brakes before the next session, points more towards uneven pad transfer.

May I ask if you are using the BMW M Sport pads with the stock rotors? Or do the rotors need to be changed as well?

[mlhj83]

Originally Posted by Chagrin

May I ask if you are using the BMW M Sport pads with the stock rotors? Or do the rotors need to be changed as well?

I'm using them with the rotors that came with the car from factory, and not had any issues (5 track days). I'm aware that there are different OEM rotors specifically for the Sport pads which have different part numbers to the rotors that came from factory, but nobody knows the difference as they look exactly the same; materials might be slightly different perhaps. Best to send an email to BMW customer services for a definitive answer if you are interested.

Oh, I don't use the Sport pads on the road as they are way too noisy - I see pedestrians cringe when I come to a stop. I swap to the standard pads after a track day.

[M3PO]

Originally Posted by mlhj83

Yes. Just be aware that uneven pad transfer can become permanent if you keep hammering the brakes, as the parts of the disc with pad deposits get hotter and hotter with each pass of the brake pad; more so than the parts of the disc with no deposits.

OEM pads take some time to scrub off deposits because the pads are generally quite soft and not very abrasive. Also, in general, pads are at their most abrasive when cold to slightly warm temperatures.

Interesting. The confusing part for me was that they got better if I went easier on them and were perfect at the beginning of the next session (and even on the way home for that matter). I guess the pad transfer wore off during the remainder of the session.

[mlhj83]

Originally Posted by M3PO

Interesting. The confusing part for me was that they got better if I went easier on them and were perfect at the beginning of the next session (and even on the way home for that matter). I guess the pad transfer wore off during the remainder of the session.

Sounds about right; when the pads cool, they become more abrasive, and probably cleaned the disc surface of uneven deposits. Or, your pads may have cooled to its ideal temperature range and laid an even layer of deposit all around the disc, while also spreading the existing uneven deposits evenly around the discs.

[M3PO]

Originally Posted by mlhj83

Sounds about right; when the pads cool, they become more abrasive, and probably cleaned the disc surface of uneven deposits. Or, your pads may have cooled to its ideal temperature range and laid an even layer of deposit all around the disc, while also spreading the existing uneven deposits evenly around the discs.

Cool, thanks for the explanation! Since there wasn't a degradation in braking (at least not that I noticed, track noob though), I assumed that the pads and fluid were okay.

[THE TECH]

The parts we've been working on with Racing Brake have been released. You can see details here: http://www.racingbrake.com/BMW-M3-E9...-p/2161-pu.htm

[Z K]

Originally Posted by THE TECH

The parts we've been working on with Racing Brake have been released. You can see details here: http://www.racingbrake.com/BMW-M3-E9...-p/2161-pu.htm

Are the brake calipers specific for the M3 so they use the appropriate sized brake pistons so the stock f/r brake proportioning stays the same?

[THE TECH]

Originally Posted by Z K

Are the brake calipers specific for the M3 so they use the appropriate sized brake pistons so the stock f/r brake proportioning stays the same?

That's correct.

[M3PO]

Originally Posted by THE TECH

The parts we've been working on with Racing Brake have been released. You can see details here: http://www.racingbrake.com/BMW-M3-E9...-p/2161-pu.htm

Can I ask who manufactures the calipers? Are they manufactured by the same factory that other brake vendors use for example?

[THE TECH]

Originally Posted by M3PO

Can I ask who manufactures the calipers? Are they manufactured by the same factory that other brake vendors use for example?

As far as I've been told by the owner of Racing Brake himself, they do all the mfg. themselves.

[Raucky2000]

Yup, THE TECH is all over this one...RB=great stuff.