Braking Distance CCB vs Stock

[SteveSpy]

Originally Posted by FTS

From the review of the RC-F:

"In terms of braking, the RC F stops from 60 mph in 108 feet. The M4 with optional $8000 carbon-ceramic brakes needs 98 feet, the Audi RS 5 requires 104 feet, and the old AMG 507 needed just 103 feet."

Read more: http://www.motortrend.com/roadtests/...#ixzz3ChEl2bmL

Thank you @FTS for finally answering my original post. It only took two months and countless bullshit for somebody to bring me empirical evidence to answer my question. Now we can move on.

[FTS]

You're welcome

[Maxis]

The one minor issue with ceramic composite brakes are situations when you're using the vehicle with light application on the brakes while the brakes are still cool for example when you're driving the vehicle for the first time in the morning or anytime when the vehicle has been resting for hours and the brakes are cold it will feel a little grabby but it still works.

[FTS]

Just to keep things consolidated:

Alexshop's performance test results (CCB equipped M4, stock tires, DCT); original thread:

http://f80.bimmerpost.com/forums/sho....php?t=1038740

Avg. braking distance is 308 ft or 94 m.

[Musashi]

No Performance Difference, Yet I Would Get Ccb's In An Instant...
First, would like to thank the post members for having it, this post is invaluable at gaining insight on the CCB. I have no doubt that this type of community will drive the eventual mass production of CCB's. I am not an engineer, nor a racer, but am relying on basic scientific or technical knowledge to retrieve published authoritative expertise arguments and bring them here.

Summary: There is no performance difference between CCB's and high-grade , high-quality cast iron discs, and am demonstrating, as concisely as possible, why it is so, and keep math or physics to a minimum. But that aside, I would buy CCB's the first opportunity, and most certainly on the next gen M3, which I believe will probably be all carbon fiber and even more exceptional.

FORMULA 1

In the 1990s F1s evolution was reducing the braking boundaries at distances so short that overtaking was headed towards obsoletion. FIA rules altered braking regulations to increase the braking distance, which included limiting the input assist, reducing rotor diameter etc. Dimension wise:

11.3.2 All discs must have a maximum thickness of 28mm and a maximum outside diameter of 278mm (Source: F1)

Weight: 4 discs = 1.5kg or 13.2 lbs total. That is over 30lbs shaved off regular CCB's. In addition, wheel size limits the CCB disc, and that will change as larger wheels have already been tested in F1. However, a reminder that F1 and FIA do not want better braking or it will prevent overtaking.

Within the F1 dimensions, the only material that can deliver is CCB. Athough CCB's have a poor performance below 400°C and optimum braking performance above 650°C.” (Source Racecar Engineering). Typical T= 1200 Deg C. The short acceleration and deceleration timings, F1 rotor temperature spikes over 1000 Deg C. As ABS is banned in F1, the thermal requirement prohibit cast iron as it cannot survive the temperatures. Ceramic is the only material that can do the job.

In a full season, Brembo supplies each team with the following material for two cars
(http://www.brembo.com/en/Press/Comun...hip%202014.pdf)

• 10 sets of calipers (i.e. 4 x 10 components)
• Between 140 and 240 discs (or 35 to 60 sets)
• Between 280 and 480 pads

For 20 events, averaging 350 kms race and a generous 200kms for testing and quals, total is 11,000 kms x 2 cars = 22,000kms / 35 to 60 sets or a median replacement frequency of 370kms (one race) to 630 kms per set!!! CCB's get replaced before half-life and even before 20% life is used or after one hard braking incident. F1 teams learned that anything over 200kms, CCB's may develop critical cracks that can fracture the CCB. A single braking action can also do it. Post race X-Rays and in-race failures demonstrated this amply, such as the article below.:

Tech explanation, Brembo F1 CCB failure, Tech info, Ferrari’s own CCB's: http://www.racecar-engineering.com/t...brake-systems/

As if not sufficient, 2015 F1 CCB's are changing again to improve reliability. So even CCB evolution demonstrates that CCB's are not created equal.

F80, M3 M3 GT2 PORSCHE PORSCHE GT CORVETTE ETC

Back to M3 and GT. F1s max weight is 691kgs vs 1290 / M3 GT2. As the mathematical posts above demonstrated (I decided against adding Force, Mass, acceleration, etc equations), unsprung mass matters a lot for fast cars. F1s accelerate 0-100 in 1.7 seconds, nearly 1-2 seconds faster that most GT cars. Half the weight, x 3-4 G force, higher tire footprint ratio, lower body, any F1 can slow down, for the same speed, nearly THREE times faster than the average GT.

Combined with faster acceleration, the cooling cycle for F1 CCB's is nearly HALF (1/2) the GT cooling period. And more frequent. Or disc Area is

A=πr2 CCB at 278mm = 2427 sq cm, and for 400mm= 5026 sq cm. Twice the size for commercial CCB's. Note, F1 discs are THINNER as well. So about 2.5 three times more cooling surface/volume in commercial CCB's than F1.

Energy kinetic = Ek = ½mv2. M for mass. Means that at equal speed, GT must dissipate TWICE as much energy (twice or more the mass)

Common question, “Ok, so twice the car mass, thrice the rotor, means same braking right? That Porsche or M3 will brake like the F1?”

No. Car acceleration, and traction force will relate to brute HP (400-800 hp), weight, mass, tires, temperature, unpsrung weight etc. Calculator: http://www.engineeringtoolbox.com/ca...on-d_1309.html For an M3 and Porsche 911 GT, Mass is x 2-3 higher, Traction lower, CoG higher, 1/2 vs 3/4 G Force, accelerate slower, and have more than twice the mass and Ek at the same time and space and speed. However, other variables intervene (height, CoG, traction, etc), and consequently, the braking is not just x2, but nearly 3 times slower to get the car into a safe max speed apex. Add to it ABS and longer deceleration time, these GT car cast iron discs have more than sufficient time for thermal dissipation and to cool down, since the cooling rate is similar to CCB but with more ample time to spare..

Example: at Spa-Francorchamps, at the Kemmel Straight, approaching turn 7 at Les Combres, an M3 GT2 can accelerate up to 320, then must hit the brakes the latest at the 200m marker and arrive at 100-110km/hr, whereas the F1 can do so drop from 345km/hr commencing braking at the 100-75 m marc, and could enter the turn at 120-140km/hr. In practice, everyone is a bit slower, as tire degradation and track temperature will affect this from lap to lap. http://upload.wikimedia.org/wikipedi...of_Belgium.svg

The technical data from the article attached, “Optimizing carbon- ceramic brake disc design for same-size replacement of cast iron discs” is one of many that demonstrate that there is NO difference whatsoever between CCB and cast iron performance with the larger commercial dimensions. Some fading is indeed noted, but both retain their effectiveness within the same envelope. The F1 environment is different, as the technical limitations do not allow for cast iron.

Additional articles inside academic libraries discuss the topic, but these cannot be reproduced without author permissions. Bottom-line, M3, M3 GT2, Porsche 911 GT usage, the cooling cycle is longer and more than sufficient to allow for identical performance between cast iron and CCB. Furthermore, cast iron being four times cheaper, the esteemed Porsche racers are very wise to substitute their CCB's. However, experienced racers are also experienced brakers; poor braking techniques on cast iron can push their limits, increase fading, but that does not prove, empirically, that CCB's are superior. As a base offering in some cases, such as the F80, the BMW M Performance brakes are terrific (BMW M Performance videos repeat in fast succession dozens of 250-0 km/hr braking cycles that prove their resilience). Coupled with additional pad and braking liquid modifications, all race grade sports cast iron discs are equal in performance to CCB's, and actually superior when operating below 400C,..

ANOTHER CCB PROBLEM: FRACTURE RISK

As illustrated by the F1 reality and extensive CCB testing, track degradation of CCB's is nearly identical. But CCB life-cycle is actually much shorter. A few laps on a CCB can create micro fractures that can fail catastrophically one or both front discs, and jeopardize the driver. Unless taking the CCB's and xRay-ing them after each track day, a CCB user topping 300-100 km/hr even once per lap is increasing exponentially his risk by keeping them on. In F1 they do not bother and simply discard them or give them to Brembo before they head for clock makers and become beautiful sports ornaments. For a DD, he can microfracture the CCB, and keep driving on it for months or years without knowing; but he may be one hard deceleration away from CCB fracture.

The deduction is that one cannot buy CCB’s, track them ten times for 100 laps per year, and expect a similar lifelong performance as cast irons tracked as well 100 laps per year. The risk of catastrophic failure of CCB's increases exponentially with each major deceleration. By 9th month of occasional tracking, at Indianapolis (Laguna Seca being a slower circuit), cumulative lap 80, the front CCBs are likely done and can just fracture, whereas, at their worst, high-grade cast irons will retain form and provide advanced failure feedback, such as pulsations etc while retaining integrity. This again speaks in favor of those installing cast irons for races. The fracture risk is one of those hidden risks CCB manufacturers carefully omit from the sale's pitch. But that is why they do not warrant them if tracked.

Unsprung weight: As per previous posts math, for an F1, dropping 30lbs is a significant weight reduction that can be used in KERS etc. Math in previous posts is correct, the ability to get that F1 0-100km/hr in 1.7 seconds directly relates to horse power, mass, traction. But in a car three times heavier, it does not matter as much.

Why buy CCB's? There are some outstanding reasons.

• Cost: In 250,000 kms driving two Japanese cars, I replaced 4 sets of rotors. At least two were lost to warpage, or premature corrosion related degradation impacting thermal properties, and they failed during two single braking incidents... Zing coasting lasts 10,000 hrs in salt, or about a winter. Cadmium plating lasts lifetime of rotor but is hard to come by. GT grade cast irons gave me longer lifespan (80,000-140,000 kms), but the bottom line? I spent $4,000 in brakes on a low end car. Yet, a single CCB set would have lasted me this distance and still be about half life…
• Unlimited $, you can track and replace them at will, money never an issue;
• CCB's look terrific (no one can dispute that);
• Branding;
• Somewhat better braking performance but only if comparing them with rusting cast irons in 3d year, BMW’s argument is a bit misleading. Any other time and space, or track, it is identical;
• Will drive the car DD in nice weather, spirited digressive driving, and minimal track performance;
• Zero rust: true, but most high-end luxury cars do not drive them in winter. That aside, seen quite a few Porsches driven in Canadian winters, CCB's, owners assured by the knowledge that salt will never attack the frame. That in turn, promotes better looks. As carbon and alloy frames multiply, so will be winter driving. Anti-corrosion properties cannot be ignored;
• Lifetime brakes. A rapid 250,000 kms wear on a high-end sporty car, driven 15,000 kms/year that is 16 years, quite the deal! Porsche and BMW CCB's can probably last over 350,000 kms spirited and DD and even with occasional tracking. One would have to be really unlucky to get a crack.
• 8k is not that much more for you vs overall cost of car;
• You always have access to a qualified wheel installer that WILL NEVER crack your disk mounting tires etc.
• All of the above considered, 8k is a bargain, be it a higher up-front cost.

Why not to get them

• Race track performance- no difference;
• Intend on selling car in 3-5 years, which case next owner may not accept them;
• Intend to track the car frequently and do not want to bother with spare cast iron sets;
• You hate squeal sound when the CCB's are cold, especially in winter. The -18C to -30C (-4F to -22F) we had recently (Ottawa, Montreal, twice as cold in Winnipeg), there was nowhere I could even warm up my M Performance set. 30 min drive, out of car, they are not even lukewarm... Hard braking is out of the question, too slippery even on dry asphalt with winter tires. CCB's would squeal incessantly in these conditions, meaning, Summertime car only;
• May genuinely be financially on the edge in which case an M3 is itself a doubtful commitment;
• Little to no access to specialized center that can safely remove your rims each time.

I would get them in an instant, even for my F30 if they were produced. That aside, I do believe that the cost potential for CCB's should not exceed that of cast iron (2-4k per set), but only if they were mass produced.

Thank you!!

Sources

http://www.engineeringtoolbox.com/ca...on-d_1309.html
Brembo. http://www.brembo.com/en/Press/Comun...hip%202014.pdf
http://www.surface-transforms.com/fi...march_2014.pdf (Attached)
F1 Regulations, http://www.formula1.com/inside_f1/ru.../8696/fia.html
“F1 2014 explained: Brake systems”, Racecar Engineering, last edited Jul 2014, http://www.racecar-engineering.com/t...brake-systems/

Attachments

“Optimising carbon- ceramic brake disc design for same-size replacement of cast iron discs.” SMMT Innovation and Technology, Spring 2014, http://www.surface-transforms.com/fi...march_2014.pdf
and Brembo's communique..
Attached Images
File Type: pdf smmt_surface_transforms_article_march_2014.pdf (396.2 KB, 2 views)
File Type: pdf Brembo_F1 World Championship 2014.pdf (339.0 KB, 2 views)

[FTS]

Although a good attempt, information in your post is a little misleading: F1 has been using Carbon-Carbon rotors for sometime, which is completely different then Carbon-Ceramic compound. Now Brembo has CER, which I do not even know its manufacturing process and there is little information on the compound, which is an evolution to Carbon-Carbon.

MovIt has had CCF as an evolution to CCB and now also has CER. All of these technologies supposedly provide better brake energy management overall compared to CCB.

Regardless, you are comparing F1 braking technology to street systems, which is not comparable, and all these rotor compounds and construction yield different results compared to CCBs, which is apples to oranges.

One of the beat parts of CCBs for street use is that they do operate very well at even freezing temps, they give very little to their iron cousins; otherwise street car manufacturers would not put them on our cars risking many law suits

[sham4]

Surely 6 Pistons must be better braking than 4 piston? Having driven both they definitely feel different.

[CanAutM3]

Originally Posted by sham4

Surely 6 Pistons must be better braking than 4 piston? Having driven both they definitely feel different.

Have your read the thread ?

[Lotus99]

So I'm debating which brakes to order with my car, and came across this thread. Was hoping that it would've been updated in the past 2 years.

I track mine maybe 5 days a year. What would you guys recommend if I was willing to even use track pads on those days. I've never changed out pads before, but I am not a mechanical dimwit, as I can do stuff like changing spark plugs, so I'm guessing this can't be that much harder?

Are there now some updates on the issues brought up in this thread?

[MasterP]

Originally Posted by Lotus99

So I'm debating which brakes to order with my car, and came across this thread. Was hoping that it would've been updated in the past 2 years.

I track mine maybe 5 days a year. What would you guys recommend if I was willing to even use track pads on those days. I've never changed out pads before, but I am not a mechanical dimwit, as I can do stuff like changing spark plugs, so I'm guessing this can't be that much harder?

Are there now some updates on the issues brought up in this thread?

It's easy. Punch the pins out of the caliper, remove the noise springs. Spread the pistons. Remove pads. Reverse to install.

[CanAutM3]

Originally Posted by Lotus99

So I'm debating which brakes to order with my car, and came across this thread. Was hoping that it would've been updated in the past 2 years.

I track mine maybe 5 days a year. What would you guys recommend if I was willing to even use track pads on those days. I've never changed out pads before, but I am not a mechanical dimwit, as I can do stuff like changing spark plugs, so I'm guessing this can't be that much harder?

Are there now some updates on the issues brought up in this thread?

There is nothing new posted because nothing changed.

Both will offer similar performance on track when the irons are paired with proper track pads. The issue is with CCB replacement cost with frequent track use.

[CAOZKAN]

Originally Posted by Lotus99

So I'm debating which brakes to order with my car, and came across this thread. Was hoping that it would've been updated in the past 2 years.

I track mine maybe 5 days a year. What would you guys recommend if I was willing to even use track pads on those days. I've never changed out pads before, but I am not a mechanical dimwit, as I can do stuff like changing spark plugs, so I'm guessing this can't be that much harder?

Are there now some updates on the issues brought up in this thread?

Let me try to give you some of my first hand experience about CCB ownership:
Pros
1-they are really really good on track vs steel especially on repetitive braking
2-they are looking great and have no dust
3-If you don't track them they will most probably outlive your car
Cons
1-Very costly to replace rotors + pads ( I have changed mines after 8-10 track days even though BMW said that their weights were enough, their markers were gone and they were making a heavy noise, vibration and pull, I couldn't bare with them and thankfully I bought from one forum member 4 pads + rotors for 4.5k$.)
2-cold and rainy performance of them, sometimes, close to dangerous. When they are cold on the long autobahn runs, they don't work for few seconds which scary and dangerous.
3-they squeak no matter what I did

All things said, I still love them and will replace them again if I can find a cheap offer after the new set is gone. Otherwise I will most probably go with iron replacements.

[Lotus99]

Originally Posted by CanAutM3

There is nothing new posted because nothing changed.

Both will offer similar performance on track when the irons are paired with proper track pads. The issue is with CCB replacement cost with frequent track use.

Would you define 5 track days a year as "frequent track use"?

I read the whole thread in one shot, and the main points of discussion seemed to center around whether CCB's offer a shorter stopping distance or not (there weren't direct M4 results, only Porsche ones to deduct from), and whether over time the CCB's would need replacement with track use, despite their claim that they should last a really long time, in which case, for someone tracking, they're better off sticking to iron rotors.

PS Which pads do you use for your track days?

Originally Posted by CAOZKAN

Let me try to give you some of my first hand experience about CCB ownership:
Pros
1-they are really really good on track vs steel especially on repetitive braking
2-they are looking great and have no dust
3-If you don't track them they will most probably outlive your car
Cons
1-Very costly to replace rotors + pads ( I have changed mines after 8-10 track days even though BMW said that their weights were enough, their markers were gone and they were making a heavy noise, vibration and pull, I couldn't bare with them and thankfully I bought from one forum member 4 pads + rotors for 4.5k$.)
2-cold and rainy performance of them, sometimes, close to dangerous. When they are cold on the long autobahn runs, they don't work for few seconds which scary and dangerous.
3-they squeak no matter what I did

All things said, I still love them and will replace them again if I can find a cheap offer after the new set is gone. Otherwise I will most probably go with iron replacements.

Thx for pointing out the negatives too... I was lucky enough over the weekend to take out a Comp Pack M4 with CCB's for a nice test drive, and man, are the CCB's nice. It was a lovely dry day, and the car only had 100 miles on it, but they didn't squeak on me once.

When I got back and was talking to my sales advisor about them, he really tried to stress that quite a few of his clients with CCB's have found the squealing to be pretty bad (and not fixable).

But most importantly, especially given where I live (Vancouver, Canada, where it rains a lot during the year), he said quite a few have had pretty scary encounters when using the pads the first time in wet weather, in that they barely worked. Which would put me off of them for sure...

So it sounds like your experience with them is fairly representative of what he told me...

[CAOZKAN]

Originally Posted by Lotus99

Would you define 5 track days a year as "frequent track use"?

I read the whole thread in one shot, and the main points of discussion seemed to center around whether CCB's offer a shorter stopping distance or not (there weren't direct M4 results, only Porsche ones to deduct from), and whether over time the CCB's would need replacement with track use, despite their claim that they should last a really long time, in which case, for someone tracking, they're better off sticking to iron rotors.

PS Which pads do you use for your track days?

Thx for pointing out the negatives too... I was lucky enough over the weekend to take out a Comp Pack M4 with CCB's for a nice test drive, and man, are the CCB's nice. It was a lovely dry day, and the car only had 100 miles on it, but they didn't squeak on me once.

When I got back and was talking to my sales advisor about them, he really tried to stress that quite a few of his clients with CCB's have found the squealing to be pretty bad (and not fixable).

But most importantly, especially given where I live (Vancouver, Canada, where it rains a lot during the year), he said quite a few have had pretty scary encounters when using the pads the first time in wet weather, in that they barely worked. Which would put me off of them for sure...

So it sounds like your experience with them is fairly representative of what he told me...

No problem at all. This is only my experience and I'm on my second set and after one track day, they already started to squeak but I learnt to leave with it. Maybe most of the people don't track them and this way they don't squeak :

[darkbluemn]

Originally Posted by CAOZKAN

No problem at all. This is only my experience and I'm on my second set and after one track day, they already started to squeak but I learnt to leave with it. Maybe most of the people don't track them and this way they don't squeak :

Squeak is normal I believe. I went to M school and drove M3/4 with CCB for 2 days and beat them with hardest brake all the time. Everyone do the same for every M school, and those cars perform consistently except noise. You cannot avoid the worse and worse noise for tracking your car.

[Lotus99]

Originally Posted by CanAutM3

There is nothing new posted because nothing changed.

Both will offer similar performance on track when the irons are paired with proper track pads. The issue is with CCB replacement cost with frequent track use.

Interesting article I'm reading... Some snippets of it include:

At high temperatures, carbon ceramic materials are also less resistant to deformation or warping, which means that they should last a bit longer than traditional brakes.

Yet, we have people here saying theirs got deformed after track use. What's going on?

“This feature means that the wear resistance of Carbon Ceramic Material guarantees an approximate disc life of 150,000 km (93,000 miles) for road use and 2,000 km (2,400 miles) for extreme track use (e.g. Ferrari Challenge),” Michelini said.

Jesus! That's a huge difference in wear! Would they define HPDE days as "extreme track use"? And if so, how many days is that?


http://www.autoguide.com/auto-news/2...ic-brakes.html

[CanAutM3]

Originally Posted by Lotus99

Interesting article I'm reading... Some snippets of it include:

At high temperatures, carbon ceramic materials are also less resistant to deformation or warping, which means that they should last a bit longer than traditional brakes.

Yet, we have people here saying theirs got deformed after track use. What's going on?

“This feature means that the wear resistance of Carbon Ceramic Material guarantees an approximate disc life of 150,000 km (93,000 miles) for road use and 2,000 km (2,400 miles) for extreme track use (e.g. Ferrari Challenge),” Michelini said.

Jesus! That's a huge difference in wear! Would they define HPDE days as "extreme track use"? And if so, how many days is that?


http://www.autoguide.com/auto-news/2...ic-brakes.html

a little.

The article you quoted is misleading, Carbon Ceramic brakes (CCB) have nothing to do with the Carbon-Carbon brakes used in high-end racing.

http://f80.bimmerpost.com/forums/sho....php?t=1239580
http://f80.bimmerpost.com/forums/sho....php?t=1302752
http://f80.bimmerpost.com/forums/sho....php?t=1378641

With the high temperature generated with track use, the fibres in the CCB matrix will oxidize. That is why CCB wear is evaluated on lost weight. It has been demonstrated that CCB will wear just as fast if not faster than standard iron rotors with track use.

With street only use, they will likely outlive the car itself.

BTW, 2000km = 1200 miles