Why Bimbo and not Ah Pui Racing or others?

[Shaun]

Shaun,
Now that the front is definitely more fade resistant than stock, the increase in torque/bite is also quite significant. I was wondering if the Electronic Brake Force Distribution widget in the car is able to apply optimum braking power to all 4 wheels during an hard/emergency stop.

Hi Tanz, I can't say for sure since I've not studied late generation BMW brake systems in any detail, but I do believe that it still will be able to because the brake modulation F-R is still based on a feedback loop and not just constants.

Even IF the range of distribution is exceeded (IF there even is a limit), and you get some sort of error code or light come on to check the brakes, the braking is still biased to the front and still easy to control. You only really have to start worrying if you go to semi-slicks of slicks... this is the only way that weight F-R weight transfer is going to change since on street tires, the transfer is overwhelmingly limited by tires and not brakes. The BMW engineers would have been expecting this and I'm quite sure they would have factored in sufficient span of adjustment into the EBFD. Other cars seem to be running brake kits and tire types with no problems, so it would appear that you can too.

I guess a couple of braking and brake-turning tests in a wide open space will give you a very good indication of how good/safe things are right now compared to stock. Reduced decel or increased looseness in the rear would indicate problems or too much of a mismatch, but I doubt it'll happen.

 

[Tanzy]

Shaun,

Thanks! Sounds safe. I'll go do a brake test later.

 

[Tanzy]

Tried to bed in the pads today. Not very successful with the front rotors. Rear brakes are obviously bedded in. Surface of rear rotors is matt and powdery looking. Fronts are still kinda shiny. Experienced green fade on the 10th braking manuever. Pedal was firm and depressed all the way but decreased stopping power was felt. Completed 15 cycles before running out of road and had to cruise to let brakes cool down.

 

[Shaun]

What bedding process did you run?

 

[Tanzy]

Shaun,

Maximum braking before ABS kicks in from 120 to 20 km/h. Repeated 15 times in rapid successions. Could smell the brakes by the 8th or 9th time.

I don't think this is aggressive enough for the racing pads.

 

[Shaun]

I don't think that's the right way to bed them in! There is a process desciribed across many sites and they are largely the same. I do not recall exact details, but I know none of them describe anything as violent as multiple 120-20s. I seem to recall getting them up to temp slowly so the whole pad is hotish before doing the heavy stuff.. and even then having cooling periods in between. try searching

 

[Tanzy]

Shaun,

From Stop Tech website

We typically recommend a set of ten partial braking events, from 60mph down to 10mph, followed immediately by three or four partial braking events, from 80mph down to 10mph. Alternately, a set of eleven stops, from 80mph to 40mph, or a set of seven stops, from 100mph to 50mph, would be approximately the same. As with street pads, each of the partial braking events should achieve moderate-to-high deceleration (about 80% of the deceleration required to lock up the brakes and/or to engage the ABS), and they should be made one after the other, without allowing the brakes to cool in between.

 

[Shaun]

Funny, the Baer and Wilwood sites prescribe more gentle break ins, which kind of make more sense to me.. allowing to heat to saturate the pad first and even out across in before going really hard? Even Fred Puhn in his brake book recommends getting them up to temp gradually.

dunno man.. I guess the definition of gradual is different to different companies and people, but personally I would err on the side of taking too long rather than heating too quick.. esp when pad material and dimensions are different.

 

[Tanzy]

Shaun,

OK try again tonight.



Also, to show off a bit.

 

[Racebred]

aiyoh, tanzy why you bed in the brakes like that.... all you hd to do is to drive normally, with gentle braking, for about 2 full tanks and all is complete.

new brake pad smell is expected, and normal. you'll smell the same thing again when you change pad next time round.

and one thing, even with all my hard street driving, hard decel at NSH, or continunous track lappings in sepang (>10laps at one go), i never overworked my brakes or experience decrease in braking perf before leh. you quite hiong. heheheh but then again i'm quite a gentle braker.

 

[Tanzy]

Quite fun to see smoke coming out of the brakes and yet that thing can still stop well. AP must be even better. I think it will brake even when it is on fire!