RacingBrake on our 135i race car

[scottn2retro]

Hi All -

We moved up in class this year to a prepared class build, which meant we could go with aftermarket brakes. So I stopped by RacingBrake.com in Fullerton to see what they had.

Warren took me on a tour of the shop and I was impressed with the quality of the hardware he uses - forged rotor hats, stainless steel pistons with hollowed out cut for weight, connecting hardware (we've actually had connecting hardware break from other vendors). I also liked his patented rotor/hat alternating connecting pattern that allows more airflow.

So Warren and his team came up with a 4 pot setup for the front that allowed for a larger diameter rotor (380 mm), a 4 pot rear setup and his XR70 racing pads. They work well on the track (in fact the harder you lay on them, the better they work), with the only thing someone new to them would need to be aware of is a rythmic sound that they produce under braking. We believe it to be kind of a wind instrument effect caused by the holes in the cleaning slots.



The front kit under an 18" wheel.


The RacingBrake rear kit and the OEM rear rotor for comparison


The rear kit installed. Note the holes in the slots. Those aid in preventing stress cracks, but also are what create the sound that takes getting used to under braking.



How the rear brakes look under the rear wheel



We used some rotor temp paint to see how they did at Miller Motorsport Parks (a track with high speeds and some hard braking zones). Both pics below are from the same front rotor. Note that the paint records the highest instantaneous temp and that it is not the same temp on all parts of the same rotor.

[chris82]

Wow that's a serious setup, I'd like to hear what this noise under braking sounds like haha

edit: What size are the tires?

[ShocknAwe]

Looks amazing, thanks for posting this up. What was the overall weight reduction per corner (If there was one with the rotor size) moving to this equipment?

[Freon]

Looks great!

[Eddie135]

It's awesome quality!!!

Do they have replacement rotors for front & rear to work with our stock calipers?

[andrey_gta]

Originally Posted by Eddie135

It's awesome quality!!!

Do they have replacement rotors for front & rear to work with our stock calipers?

Yes they do - Stock F+R in two piece
Fronts can be Oversized disk via a Bracket

[Eddie135]

Originally Posted by andrey_gta

Yes they do - Stock F+R in two piece
Fronts can be Oversized disk via a Bracket

Can you point me to the correct direction as to where I can buy this from?

[andrey_gta]

Master list for BMW contains BBK and Rotor only
http://www.racingbrake.com/category-s/7118.htm

BMW sub forum for them to gather Pre orders for the Rear rotor
http://forums.racingbrake.com/forumdisplay.php?f=13

[arcticcat522]

If you do get some, be sure they fit with your rims. I bought some used rotors, and the caliper rubs ever so slightly on the rim after install

[dcaron9999]

Originally Posted by arcticcat522

If you do get some, be sure they fit with your rims. I bought some used rotors, and the caliper rubs ever so slightly on the rim after install

Oversized or standard size RB rotors?

[dcaron9999]

Originally Posted by Chrisar82

Wow that's a serious setup, I'd like to hear what this noise under braking sounds like haha

Same here!

Wonder if these holes get clogged by pad deposits, and if the slots have a "cheese grating" effect on the pads.

[dcaron9999]

Thinking about these rotors, SS pistons, high temp dust boots, and SS brake lines. Nice project for this winter ...

[project jayden]

those are absolutely beautiful! Someday i hope to own a set

[scottn2retro]

Originally Posted by Chrisar82

Wow that's a serious setup, I'd like to hear what this noise under braking sounds like haha

edit: What size are the tires?

We use 27/65x18 slicks (270mm wide/650mm diameter). It sounds like there is a vibration, but there isn't one, so it's just kind of a wierd thing to get used to.

Here is a testimonial from one of the drivers, Gary St. Amour:

"The 135i was also equipped with RacingBrakes. I have driven this 135i before and at the time it had stock brakes. I had a lot of brake issues with the pedal sinking to the floor and just not stopping well for race conditions, not very confidence inspiring. Scott has upgraded the car to Racing Brakes and they performed fantastic. I went in to the weekend a little apprehensive about the braking issues and so eased into using them harder and harder. I had no problems whatsoever, even when I got them very hot I was still able to go deep into brake zones after several laps and pad wear was minimal over 420 track miles. I have driven cars with other race brake manufacturers and the RacingBrakes are on an even par with them, I would recommend RacingBrakes as a confidence inspiring upgrade anytime."

[ShocknAwe]

Looks to be about a 5k upgrade for front and rear. Not bad for something that works so well I think.

[The HACK]

Originally Posted by scottn2retro

We use 27/65x18 slicks (270mm wide/650mm diameter). It sounds like there is a vibration, but there isn't one, so it's just kind of a wierd thing to get used to.

Yep. Weirdest thing ever. Not entirely sure it's aerodynamic related sound because of the holes, but I can hear it on my MZ4 Coupe equipped with same rotor too.

Best I can describe it, and this may be giving away my age, was it sounds like that thing that Crocodile Dundee used to communicate with his aborigine friend in the outback...A "wom-wom-wom" sound that various slightly in pitch.

Just for sh*ts and giggles, I'm exploring more pad options, and it appears Cobalt makes compounds that uses RB caliper pad shapes too, so you're not limited to just RB pads. Although their pads are excellent too...But just throwing it out there, if you're worried that you're locked in to their pads using RB calipers, you're not.

[arcticcat522]

Originally Posted by dcaron9999

Oversized or standard size RB rotors?

Oversized.

[scottn2retro]

Originally Posted by dcaron9999

Same here!

Wonder if these holes get clogged by pad deposits, and if the slots have a "cheese grating" effect on the pads.

Have never noticed the holes clogging up.

We've been working with these since early this year on tracks like COTA, Miller, Buttonwillow, Sonoma, Laguna Seca and soon Thunderhill. A variety of tracks with a varying use of brakes and the RB brakes have held up superbly. Tracks like COTA, Miller and Laguna Seca that have hard braking zones at the end of high speed straights where Sonoma, Buttonwillow and Thunderhill (5 mile config.) have more frequent uses of the brakes over the whole course.

[dcaron9999]

Originally Posted by scottn2retro

Have never noticed the holes clogging up.

We've been working with these since early this year on tracks like COTA, Miller, Buttonwillow, Sonoma, Laguna Seca and soon Thunderhill. A variety of tracks with a varying use of brakes and the RB brakes have held up superbly. Tracks like COTA, Miller and Laguna Seca that have hard braking zones at the end of high speed straights where Sonoma, Buttonwillow and Thunderhill (5 mile config.) have more frequent uses of the brakes over the whole course.

What pads have you been using? Are you using flex piping for cooling?

[scottn2retro]

Originally Posted by dcaron9999

What pads have you been using? Are you using flex piping for cooling?

I'm using the RB racing XR70 compound and at this point I'm using cooling hoses, but based on the temps of the rotors (remember, the paint records the maximum instaneous temperature which will be higher than the average temperature) and the operating range of the pads, we're looking are running without the hoses and see if they work even better.

[dcaron9999]

Originally Posted by scottn2retro

I'm using the RB racing XR70 compound and at this point I'm using cooling hoses, but based on the temps of the rotors (remember, the paint records the maximum instaneous temperature which will be higher than the average temperature) and the operating range of the pads, we're looking are running without the hoses and see if they work even better.

Interesting...
You are saying that your rotors are now get over-cooled?
Are you considering other brake pads as well, or are you locked in to RB pads due to oversize rotors?

Edit: just went to your first post again, and remembered you are using a full double axle BBK set up.
This is definitely not on my to do list, due to costs. I was thinking on going with an RB caliper rebuild kit, SS lines, and perhaps front rotors (either RB or quality blanks). I will also likely continue to use aftermarket brake pads (PFC08) with some cooling hoses. The PFC08 are simply awesome as a dual duty pad, with surpisingly no noise on the street, and quite adequate on the track with minimal fade when rotors and pads get too hot ...

[Ginger_Extract]

Originally Posted by scottn2retro

I'm using the RB racing XR70 compound and at this point I'm using cooling hoses, but based on the temps of the rotors (remember, the paint records the maximum instaneous temperature which will be higher than the average temperature) and the operating range of the pads, we're looking are running without the hoses and see if they work even better.

This backs that statements from Warren @ RB, who at times has been quoted as saying not to using ducting or additional cooling with his specific rotors. As always, YMMV.