RacingBrake Carbon Ceramic Rotor Install

[MrSkute]

I haven’t had issues with the longer bolts but I’ve only done the break-in since I had to travel for work. I’ll take a look over the weekend.

 

[Brokenblinker]

Do these rotors move the brake bias at all?

 

[kitkat]

Do these rotors move the brake bias at all?

I was wondering why the move to a larger front rotor with a ring of unswept area. This seems like it would increase front brake torque, but for what purpose?

 

[Brokenblinker]

I was wondering why the move to a larger front rotor with a ring of unswept area. This seems like it would increase front brake torque, but for what purpose?

Yeah, if you are using the same caliper piston and it's just acting on a bigger radius, this will lead to significant understeer under braking

 

[Eagle7]

I was wondering why the move to a larger front rotor with a ring of unswept area. This seems like it would increase front brake torque, but for what purpose?

They already had these for the McLaren, and they fit the Emira, so rather than go to the expense of creating a new rotor just for the Emira, they made them part of the Emira set. It seems they are going to make a custom hat for the front for the alignment set screw though.

 

[kitkat]

They already had these for the McLaren, and they fit the Emira, so rather than go to the expense of creating a new rotor just for the Emira, they made them part of the Emira set. It seems they are going to make a custom hat for the front for the alignment set screw though.

So you’re saying convenience instead of properly developing an Emira kit?

 

[Brokenblinker]

If anyone knows the brake bias stock, we could compute the change in distribution based on the updated geometries.

In the GR86/BRZ community, people have worked out spreadsheets for all of the aftermarket brake setup options.

In this case, I think the community is a bit smaller so maybe that doesn't exist. I'd sure want to know how I'm changing bias before spending this much.

 

[Eagle7]

So you’re saying convenience instead of properly developing an Emira kit?

Kinda sorta but only for the front brakes which are slightly larger. The rears are the same size as factory. It's not unusual for after-market brake upgrades to go with bigger rotors in the front, and often 6 pot instead of 4 pot calipers. By using the McLaren front rotor, they're able to offer a full CCB kit for the Emira for a much lower price than having a custom front rotor built just for the Emira. Whether that's "properly" or not is up to the customer. Doesn't bother me. The lighter weight and dramatically reduced brake dust works for me. Since I'm not going to take my car to the track, they're basically a lifetime upgrade.

Based on what @MrSkute is saying about performance, I'm also in favor of more linear and less grabby braking. Soon as the weather warms up, I'll install them and report on the results.

 

[Eagle7]

If anyone knows the brake bias stock, we could compute the change in distribution based on the updated geometries.

In the GR86/BRZ community, people have worked out spreadsheets for all of the aftermarket brake setup options.

In this case, I think the community is a bit smaller so maybe that doesn't exist. I'd sure want to know how I'm changing bias before spending this much.

Doesn't the ABS and other computers in the Emira adjust for this? You're removing over 6 lbs per front rotor with the RB CCB rotors which should improve braking. It's obviously going to change the braking characteristics compared to the stock iron rotors, but that's something you adjust to as a driver with a bit of test driving. If you're a trail-brake finesse driver, you'll adjust to it just like you do as the brakes heat up. If you're a hard stomp braking driver, you'll do the same thing.

 

[Brokenblinker]

"should improve braking"


It depends on what you mean by "improve". You want front and rear to lock up at the same time to maximize braking distance. If front locks up first, you will understeer and not slow down as fast. If back locks up first, you will oversteer and not slow down as fast.

The stock brakes are already capable of locking up the wheels. Most OEM systems are already slightly front biased to not spook normal drivers with limit oversteer.

Therefore if braking performance is "improved" as you describe (you really mean it slows the front down faster by applying more force and having less rotational inertia) in the front only, the car will go FURTHER away from an appropriate brake bias and stopping distances probably increase.

If the dust and feel outweigh the performance for you, that can still be a reasonable purchase decision.

PS you can adjust to the feel and brake differently, but you can't do anything to the bias as a driver. You can try and drive around it, but it will always be further from optimal.

 

[Eagle7]

"should improve braking"


It depends on what you mean by "improve". You want front and rear to lock up at the same time to maximize braking distance. If front locks up first, you will understeer and not slow down as fast. If back locks up first, you will oversteer and not slow down as fast.

The stock brakes are already capable of locking up the wheels. Most OEM systems are already slightly front biased to not spook normal drivers with limit oversteer.

Therefore if braking performance is "improved" as you describe (you really mean it slows the front down faster by applying more force and having less rotational inertia) in the front only, the car will go FURTHER away from an appropriate brake bias and stopping distances probably increase.

If the dust and feel outweigh the performance for you, that can still be a reasonable purchase decision.

PS you can adjust to the feel and brake differently, but you can't do anything to the bias as a driver. You can try and drive around it, but it will always be further from optimal.

I don't want the brakes to lock up at any time. You're sliding and not in control at that point. That's the whole purpose of ABS to rapidly pulse modulate the brakes to prevent lock up. In the old days before automated anti-skid systems, I used to pulse the pedal manually to keep the brakes from locking up the wheels. Modern ABS systems are much more sophisticated and much better at that now. That's a good thing, which is probably why even in Track mode, ABS is still active.

Keep in mind this isn't a track car. It wasn't specifically designed and built for track. It's set up for street use. If you want to go dedicated track, then you should add the components for that, and set the car up accordingly. There are probably things in the Emira GT4 parts bin that you could take advantage of if that's where you want to go with your car.

 

[Brokenblinker]

I don't want the brakes to lock up at any time. You're sliding and not in control at that point. That's the whole purpose of ABS to rapidly pulse modulate the brakes to prevent lock up. In the old days before automated anti-skid systems, I used to pulse the pedal manually to keep the brakes from locking up the wheels. Modern ABS systems are much more sophisticated and much better at that now. That's a good thing, which is probably why even in Track mode, ABS is still active.

Keep in mind this isn't a track car. It wasn't specifically designed and built for track. It's set up for street use. If you want to go dedicated track, then you should add the components for that, and set the car up accordingly. There are probably things in the Emira GT4 parts bin that you could take advantage of if that's where you want to go with your car.

Yeah of course ABS exists. The point is it will kick in (which is not good for general pad/rotor wear but maybe doesn't matter for ceramic) much earlier than it would otherwise before the brake bias was messed with.

If you never plan on hard braking during spirited driving or track, no worries, you probably won't notice the understeer as much.

 

[Eagle7]

Yeah of course ABS exists. The point is it will kick in (which is not good for general pad/rotor wear) much earlier than it would otherwise before the brake bias was messed with.

If you never plan on hard braking, no worries.

Any braking is not good for pad/rotor wear. They're a consumable, like tires. If you don't want pad/rotor wear, don't drive your car, then you won't have to worry about bias or wear. No worries indeed.

 

[Brokenblinker]

Any braking is not good for pad/rotor wear. They're a consumable, like tires. If you don't want pad/rotor wear, don't drive your car, then you won't have to worry about bias or wear. No worries indeed.

It's sounds like you're talking about general wear which is very different than ABS abuse which usually create warbles from uneven deposits etc. probably doesn't matter for ceramic.

 

[Brokenblinker]

Also, I am not trying to convince you this is a bad mod. On the contrary, it seems awesome for you and I hate brake dust.

But prospective buyers should know that this probably significantly moves the brake bias which will mess with limit braking for people that care about driving hard.

 

[cedricchew]

I may have missed this, but how much lighter are these rotors over stock?

 

[kitkat]

Kinda sorta but only for the front brakes which are slightly larger. The rears are the same size as factory. It's not unusual for after-market brake upgrades to go with bigger rotors in the front, and often 6 pot instead of 4 pot calipers. By using the McLaren front rotor, they're able to offer a full CCB kit for the Emira for a much lower price than having a custom front rotor built just for the Emira. Whether that's "properly" or not is up to the customer. Doesn't bother me. The lighter weight and dramatically reduced brake dust works for me. Since I'm not going to take my car to the track, they're basically a lifetime upgrade.

Based on what @MrSkute is saying about performance, I'm also in favor of more linear and less grabby braking. Soon as the weather warms up, I'll install them and report on the results.

I think i’d like to hear from RacingBreak on the topic because they’ve been pretty quiet in the forum recently.

 

[Eagle7]

I may have missed this, but how much lighter are these rotors over stock?

In total for all 4 wheels they're 23.34 lbs lighter. Here are the individual weights.

 

[Eagle7]

I think i’d like to hear from RacingBreak on the topic because they’ve been pretty quiet in the forum recently.

I'll see if @Warren-RB or Javier is watching.