Ceramic Brakes --- Porsche -vs- Ferrari

Perhaps there is a disk thickness difference? (ie we get thicker and thus they have less a tendency to crack) Just thinking out loud.

 

Ferrari, as does Mercedes, gets ceramic brake discs from Kilometro Rosso (http://www.brembo.com/ENG/Cars/BremboCars/BremboCeramicBrakeSystems.htm) a joint venture between Brembo and DiamlerChrysler. Porsche and Alcon (who supplies them to Brabus) get their ceramic discs from SGL Carbon (http://www.sglcarbon.com/sgl_t/brakedisc/index.html), originally developed by both Porsche and SGL Carbon.
Brembos process of making the discs out of chopped silicon carbide is supposed to be more economical but has yet to be seen with the current prices. SGL Carbons discs use silicon infiltrated carbon fiber.
I haven't heard much on the performance of the discs. I have heard of someone changing from the steel discs on their C4 and not noticing and change in stopping distance, just lighter unsprung weight.
Porsche is working on the second generation of PCCB discs for an option on the new 997 3.8 S.

 

That suprises me a little being that SGL Carbon has stated high mu (coefficient of friction) than that of steel discs. Its pretty well known that silicon carbide has a pretty high mu. With regards to the cracking discs, it may be due to the high rigidity of the carbon fiber core of the SGL Carbon discs as the silicon only seeps so deep in the infiltration process (on purpose). I can't say this for sure, this is only speculation. They may need some quality control or something. Anyways, they probably will try to address this problem in thier next generation discs due out soon.

 

Doody, what is replacment cost and normal intervals for the CD carbon brakes?

 

CS* I cant type today (or much of ever for that matter)

 

Ok, I'm kinda lost here! Why would you pay a lot more for brakes that are advertised as better for the track, then go with steel brakes on the tracK?????

#2 CS has Carbon brakes. I thought also the Ceramic and Carbon are different. I also thought that Ceramic worked faster than the Carbon which need more heat to get better stopping.
And if I am right and Carbon is different than Ceramic, are 360CS Carbon rotors and pads and Porsche Ceramic rotors and pads, or are the mixed like CS Carbon rotors and Ceramic pads etc?

 

Before fade becomes an issue, I'm sure the limiting factor in stopping distance on any car is tire performance. If you can reach incipient lock-up with steel brakes, there will be no performance benefit with carbon, ceramic, or anything else. After multiple stops, of course, fade resistance becomes a factor and that is where the exotic MAY outperform the steel. But at what cost?

Gary

 

You do have to look at the initial bite on the brake disc. Braking isn't an instantaneous on and off. Alcon and Brembo have gone to multi-pad setups to get higher initial bite from more leading pad edges. Drilled discs also provide initial bite. They rely on physical impedement of the brake discs. A higher coefficient of friction will provide higher initial bite without reducing the rotor life.

 

I suspect ferrari does not have an issue with their rotors because they are a lot larger and likely have a better cooling.

By the way on my GT2, even before the first track day, the brakes did not work very well when cold or very hot. They would not fade, they would basically not grab. I have experienced a similar issue during some spirited driving and lost confidence in the system.

In theory, I believe PCCB provides better stopping than steal because of the smaller unsprung weight. In reality, my GT2 stops a lot better since I have installed steel rotors...

AW

 

Hi guys,
I wanted to chime in on this one.
I was an engineer with Brembo until 2002. I had a small part in developing the CCM Enzo brakes.

The Porsche PCCB brake rotors are made for Porsche by a German company.
The Ferrari CCM is a Brembo development from Italy.
Brembo produces the calipers and suspension components for all current Porsches, but Porsche did the rotor and brake pad combination themselves for the PCCB.
There are many minor differences between the composition and productiuon technique between the PCCB and CCM rotors. Porsche has been having many problems with the rotors cracking during hard use. This is mostly due to an issue with a binding material breaking down. Many GT2 owners are switching to iron rotors for track days, which seems to beg the question as to the validity of the whole concept. The Ferrari CCM rotors have not had these problems as of yet.
The carbon-ceramic rotor technology is still very young, and the reality is that Porsche simply rushed the product a bit in order to be first to market.
I have no doubt that in time they will sort out the issues.
Brembo took a bit more time and seems to have a functionality edge currently. Understand also that even at the ridiculous prices being charged for the parts, Brembo and Porsche have spent vast amounts of money on the R&D and will not see any return for some time to come.

Also know that the CCM material is not the same as carbon-carbon, which has been used for decades in high level racing. Carbon-carbon works well only with heats that would cripple a iron rotor system. the point of CCM is to get the high temp functionality and light weight of carbon, with the ability to functiuon well from cold and without NVH issues. It does not produce a higher coeficient of friction than iron rotors, and it is very limited in pad choices, as all the fromulations for iron discs will not work well or at all with CCM. Being inherintly lighter, it can also use a larger rotor for more thermal capacity and braking leverage. Both are large advantages on a road corse or track day.

Anyway, thought two cents from an insider might help.
Eric

 

This is a quote from SGL Carbon's site:
"Carbon-Ceramic brake performance is revolutionary. The ceramic brake disc achieves not only very high, but also consistent frictional coefficients, maintaining them independent from temperature and weather conditions."
Silicon Carbide does have an inheirantly high coefficinet of friction as I mentioned above.
Carbon-Carbon brake discs also work on high temperature chemical friction properties as well. I'm not too familiar with it though.

 

I absolutely love the CS brakes on the track and simply based on feel would say that with heat the friction increases as well as that the stopping power is better than steel – however this might be caused by a combination of changes to the CS (tires, suspension, etc.)

yes the binding material seems to be the weak point that’s the reason I believe that a lot of the problems are caused by excessive heat especially impacting the pads

Article from http://www.ai-online.com/issues/article_detail.asp?id=257 that discusses CC and CCM

“How CCM is made
The Formula One-inspired CCM brake (above) is used to stop the Enzo Ferrari’s 660 horses (below).

Carbon braking bands for competition are typically made using long, resistant carbon fibers woven together and directed flat (two-dimensional) or in space (three-dimensional) in specific and non-random directions.

Brembo CCM discs, use short carbon fibers (chop fibers), arranged randomly in defined sizes and quantities. In Formula 1 discs, the Carbon/Carbon material is obtained from the CVD (Chemical Vapor Deposition) process. This process lasts about 150 days, and the raw materials include carbon fibers and methane, the finished product consists of carbon fibers in a carbon matrix. Raw materials used for CCM discs are made up of carbon fiber, phenol resin and silicon. The fibers and resin are molded in the geometric shape of the braking band. Through a process called pyrolysis, organic substances present in the resin are carbonized and a Carbon/Carbon material is yielded where the fibers are in a carbon matrix suitable for the final silication treatment.

The silication process is called LSI (Liquid Silicon Infiltration). In this phase, the liquid silicon is infiltrated into the carbon matrix and, combining with it, generates silicon carbide (ceramic) by reaction. At this point the disc has reached the necessary resistance to abrasion by the pads, which ensures a life equal to that of the car. This is followed by surface-finishing using diamond-tipped tools. Development of this production process considerably reduces the production times of the rough disc (five days) and is the basis for the future series production of CCM units. “

Picture below from http://www.autonews.com/files/pace/winners/2003bremboccmdiscs.htm - note that the design was changed during the CS production run - this is the old version