Ceramics...is Porsche backtracking?
10-30-2003, 09:36 AM
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Ceramics...is Porsche backtracking?
This is what they currently say (typos excluded):
"...Thanks to its enhanced stability in all conditions, PCCB helps minimize braking distances in even the most extreme road and race scenarios. Inherent fade resistance provides safer deceleration from racing speeds and the system's prodigious response requires only moderate pedal inputs from the driver.
Another key benefit of the PCCB system is the remarkable durability of both pads and discs. While the actual rate of wear on all brake components – particularly pads and discs – is entirely dependent on individual driving style and, of course, vehicle usage, like-for-like testing reveals a much longer lifespan compared with conventional systems.
With its major weight savings and exceptional fade resistance, even at very high temperatures, PCCB is the ideal option for genuine competition use. It is important to note, however, that circuit racing or similar extreme driving conditions can significantly reduce the overall life expectancy of even the most durable pads and discs. It is therefore important – as with conventional steel high-performance brakes – to have all PCCB components properly checked and replaced, if necessary, after every track event."
This is what they previously said (typos excluded):
"...What's more, while metal dics suffer grooving and become fractured over time, the PCCB disc is subject only to a minimal degree of thermal erosion.....temperature is no longer a major factor in brake performance. Apart from reducing braking distances by some considerable margin-paticularly under heavy use- PCCB offers much safer deceleration from high speed as well as maximum resistance to fading.
In an emergency, PCCB responds instantly and effortlessly, with no need for excessive pedal input. What's more because braking degradation is much lower than on conventional braking systems, the typical life span of a PCCB disc- provided it is subject to normal road use only- is almost as long as that of the car itself.
A key factor in the system's phenomenal wet and dry performance is the unique pairing of copmosite pads and cross drilled ceramic disc. Because PCCB is specifically designed for the extremely high braking loads encountered on the track, it also delivers much greater levelso f safety on the road. Nevertheless, no matter how effective it might be, even the most advanced braking system does,of course, have its limits. As with every brake technology, the rate of component wear is directly dependant on individual driving style and the conditions in which the system is used.
The PCCB system as featured on the 911 GT2 delivers all the performance and duability required for competition use. As well as continuing with our rich tradition in international motor racing, PCCB offers the very highest standaards of safety for the road. through the logical application of the beat engineerin principals, Porsche has achieved amaojor innovation that is far in advance of conventional brake technologies. Specifically designed for the most demanding applications, PCCB delivers consistently high performance as well as a major reduction in both unsprung weight and brake degradation. As a result. PCCB is uniquely matched to the enormus potential of your Porsche"
The first question which comes to mind is what is "circuit racing"?. After that, everything including driving, like you experience at PDE, DE or time trialling should be covered as far as damage or premature wear is concerned. Unless of course, worn out pads damage your rotors. I assume that for warranty purposes "track use" equates to circuit racing".
"...Thanks to its enhanced stability in all conditions, PCCB helps minimize braking distances in even the most extreme road and race scenarios. Inherent fade resistance provides safer deceleration from racing speeds and the system's prodigious response requires only moderate pedal inputs from the driver.
Another key benefit of the PCCB system is the remarkable durability of both pads and discs. While the actual rate of wear on all brake components – particularly pads and discs – is entirely dependent on individual driving style and, of course, vehicle usage, like-for-like testing reveals a much longer lifespan compared with conventional systems.
With its major weight savings and exceptional fade resistance, even at very high temperatures, PCCB is the ideal option for genuine competition use. It is important to note, however, that circuit racing or similar extreme driving conditions can significantly reduce the overall life expectancy of even the most durable pads and discs. It is therefore important – as with conventional steel high-performance brakes – to have all PCCB components properly checked and replaced, if necessary, after every track event."
This is what they previously said (typos excluded):
"...What's more, while metal dics suffer grooving and become fractured over time, the PCCB disc is subject only to a minimal degree of thermal erosion.....temperature is no longer a major factor in brake performance. Apart from reducing braking distances by some considerable margin-paticularly under heavy use- PCCB offers much safer deceleration from high speed as well as maximum resistance to fading.
In an emergency, PCCB responds instantly and effortlessly, with no need for excessive pedal input. What's more because braking degradation is much lower than on conventional braking systems, the typical life span of a PCCB disc- provided it is subject to normal road use only- is almost as long as that of the car itself.
A key factor in the system's phenomenal wet and dry performance is the unique pairing of copmosite pads and cross drilled ceramic disc. Because PCCB is specifically designed for the extremely high braking loads encountered on the track, it also delivers much greater levelso f safety on the road. Nevertheless, no matter how effective it might be, even the most advanced braking system does,of course, have its limits. As with every brake technology, the rate of component wear is directly dependant on individual driving style and the conditions in which the system is used.
The PCCB system as featured on the 911 GT2 delivers all the performance and duability required for competition use. As well as continuing with our rich tradition in international motor racing, PCCB offers the very highest standaards of safety for the road. through the logical application of the beat engineerin principals, Porsche has achieved amaojor innovation that is far in advance of conventional brake technologies. Specifically designed for the most demanding applications, PCCB delivers consistently high performance as well as a major reduction in both unsprung weight and brake degradation. As a result. PCCB is uniquely matched to the enormus potential of your Porsche"
The first question which comes to mind is what is "circuit racing"?. After that, everything including driving, like you experience at PDE, DE or time trialling should be covered as far as damage or premature wear is concerned. Unless of course, worn out pads damage your rotors. I assume that for warranty purposes "track use" equates to circuit racing".
10-30-2003, 02:57 PM
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The definition of "track use" will depend in part on your dealer but considering the price for new PCCB rotors I'd expect that even a DE event would fall under that category and cause a warranty claim to be denied. I didn't want to find out firsthand which is one of the reasons I changed my order to drop the PCCB option.
10-30-2003, 03:01 PM
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Simple enough... never tell the dealer about any track use. I doubt as if it could be that simple, especialy if you have a roll bar/cage installed. But how would they know otherwise.
10-30-2003, 03:11 PM
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Well my dealer usually has a couple of people at their local region's DE events so they _know_ what I do to my cars. 
That hasn't caused any problems for me though. I had some issues with the brakes on my Boxster S after a DE (pedal feel after repeated bleeding and occasionally a really long pedal) and the master cylinder was replaced under warranty.
That hasn't caused any problems for me though. I had some issues with the brakes on my Boxster S after a DE (pedal feel after repeated bleeding and occasionally a really long pedal) and the master cylinder was replaced under warranty.
10-30-2003, 03:36 PM
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Good point. Good thing my local dealer is not involved with anything relating to Porsches going to the track. 
I just hope that PCNA steps up to the plate for those that have problems. Knowing these issues are floating around, I am very reluctant to take my GT3 to the track.
I just hope that PCNA steps up to the plate for those that have problems. Knowing these issues are floating around, I am very reluctant to take my GT3 to the track.
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10-31-2003, 06:20 PM
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Gordan Murray's comment re: oxidation of carbon got me thinking.
So, I noodled over how oxygen propogates through a carbon reinforced ceramic material.
Essentially, there are two, conditional, types of Ox that can take place; low-temp reaction controlled kinetic oxidation; and high-temp diffusion controlled oxidation.
In the former , the oxygen seeps into the material through an abrasion, or nick, at the leading edge, but the rate of C oxidation is mediated by the rate at which the C is consumed under oxidation condtions on account of the low temp [750 C].
Under the latter example, the oxygen once again seeps in through an abrasion in the material, or it's leading edge, but because the temps are elevated [1250 C], the oxidation of C takes place at a diffusion dependant rate; that is, the C is consumed by a wave front of entering oxygen, and the kinetics are dependant only upon the diffusion gradient of oxygen coming into the carbon matrix. So, the carbon in the material is eaten away until it's entirely consumed.
In my mind, this bears credence to the rapid "dusting" of the rotors when/if they start to degrade, and the warning against not knicking the rotor when changing pads/wheels as it could precipitate the conditions leading up to rotor destruction as descirbed above.
10-31-2003, 10:00 PM
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Colm,
"to have all PCCB components properly checked and replaced, if necessary, after every track event."
Am I the only one who thinks this is insane? Two track events could equal the cost of an entire track car. Based on what people are reporting, if you wanted to take a car to a track with long straights (like Elkhart Lake) for a weekend, you'd probably have to bring an extra set of rotors. It's positively nuts for Porsche to expect its customers to be prepared to pay a fortune for a degradable part or completely switch to an aftermarket brake system. How can anybody with these brakes comfortably track their car, knowing that a small amount of maximal braking can destroy an entire system? How is it possible that 4 brake rotors can cost 10% of the cost of an entire GT3? This is the only Porsche product not intended for maximal use. I used to think running a CanAm car was expensive. This is ridiculous.AS
"to have all PCCB components properly checked and replaced, if necessary, after every track event."
Am I the only one who thinks this is insane? Two track events could equal the cost of an entire track car. Based on what people are reporting, if you wanted to take a car to a track with long straights (like Elkhart Lake) for a weekend, you'd probably have to bring an extra set of rotors. It's positively nuts for Porsche to expect its customers to be prepared to pay a fortune for a degradable part or completely switch to an aftermarket brake system. How can anybody with these brakes comfortably track their car, knowing that a small amount of maximal braking can destroy an entire system? How is it possible that 4 brake rotors can cost 10% of the cost of an entire GT3? This is the only Porsche product not intended for maximal use. I used to think running a CanAm car was expensive. This is ridiculous.AS
10-31-2003, 10:21 PM
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Start a log (web site) of problems to create a recall!
Maybe what is going need to happen to get Porsche to set up and either fix the rotors or offer to buy back the systems and replace them with steal systems including hubs is to create a web site that contains failure data and make it public. A very good example of this is the E46 M3 motor bearing problem that finally turned into a recall by BMW to replace the parts in the motors. Many people in the BMW world said it would never happen but it did. If a PCCB rotor can not out last a steal rotor then there is a big problem, all of us just need to track the failure or mileage before replacement. We just need to show them the failure data. Here is a link to the data collected that helped in getting the BMW motor recall.
http://members.roadfly.org/jason/m3engines.htm
http://members.roadfly.org/jason/m3engines.htm
11-01-2003, 12:39 AM
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I'll go out on a limb here by saying this but the cost for a replacement PCCB rotor should only be at most about twice the cost of a steal rotor. (Period)
Also I find the PCCB brakes very disconcerting at most times because they cool off to soon. The brake pedal and the application force that one needs to apply changes all the time and one never has the same pedal feel time after time after time. Sorry Porsche put this system is not an enjoyable system to brake the car with. Because of the every changing brake pedal feel, the rotor problems that are showing up, this system may not be safe.
If Porsche wants to offer me a reasonable and I mean reasonable price to convert / trade in my GT3 PCCB to steal rotors, Red Calibers, hats, mounts and hubs I'll take it and shut up, but in the mean time this PCCB system is not right.
Also I find the PCCB brakes very disconcerting at most times because they cool off to soon. The brake pedal and the application force that one needs to apply changes all the time and one never has the same pedal feel time after time after time. Sorry Porsche put this system is not an enjoyable system to brake the car with. Because of the every changing brake pedal feel, the rotor problems that are showing up, this system may not be safe.
If Porsche wants to offer me a reasonable and I mean reasonable price to convert / trade in my GT3 PCCB to steal rotors, Red Calibers, hats, mounts and hubs I'll take it and shut up, but in the mean time this PCCB system is not right.
Last edited by twisted; 11-01-2003 at 01:28 AM.
11-05-2003, 02:59 PM
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One more data point guys. I sent an email to the Tech Rep for Porsche Cars Canada and while he did not respond to me, he did talk to my dealer who answered me. The position of Porsche in Canada seems to be the same as the USA. If you use your car on the track, they will not warranty the brakes be they steel or ceramic. So if your PCCBs fail because of track usage, you are out of luck for a stupidly expensive replacement..
I feel seriously let down by Porsche. I've been driving them for 25 years and I'm very loyal to the brand. My loyalty was based not only on the the cars themselves but Porsche's attitude towards customers. When 996 engines and trannys failed they were replaced without hassle. When my 964 leaked because Porsche thought they could build an engine without head gaskets, it was fixed (a very complex job) for free. Now on the most expensive model one can buy, I'm told that PCCB brakes are unsuited for the track? This is unacceptable.
In my view the GT2 and GT3 are track cars. The PCCB were touted as being the definitive high performance braking system. Colm's post above spells it out clearly. The manual for a GT2 or 3 makes the intent of the car perfectly clear. To be told that PCCB are not warranted if the car is driven on a race track is a major let-down. If we were racing the cars, I'd understand. There is no warranty on any race car. Lapping and DE are not racing. Fitting PCCB to the GT2 (no option to do otherwise) implies that PCCB is fit for the intended use of the car. Not only has Porsche changed their story on PCCB the seem unwilling to admit that they made a mistake. One which those of us who paid a ridiculous price for the GT2 in the first place are condemned to pay for. Colm, please do not lose your files because I may want them in the near future. I see litigation brewing unless Porsche comes to their senses. I'd accept a conversion to steel rotors plus one replacement of the ceramic rotors as a fair deal. As others have suggested I'd store the PCCB and use the cheaper steel rotors for DE.
I feel seriously let down by Porsche. I've been driving them for 25 years and I'm very loyal to the brand. My loyalty was based not only on the the cars themselves but Porsche's attitude towards customers. When 996 engines and trannys failed they were replaced without hassle. When my 964 leaked because Porsche thought they could build an engine without head gaskets, it was fixed (a very complex job) for free. Now on the most expensive model one can buy, I'm told that PCCB brakes are unsuited for the track? This is unacceptable.
In my view the GT2 and GT3 are track cars. The PCCB were touted as being the definitive high performance braking system. Colm's post above spells it out clearly. The manual for a GT2 or 3 makes the intent of the car perfectly clear. To be told that PCCB are not warranted if the car is driven on a race track is a major let-down. If we were racing the cars, I'd understand. There is no warranty on any race car. Lapping and DE are not racing. Fitting PCCB to the GT2 (no option to do otherwise) implies that PCCB is fit for the intended use of the car. Not only has Porsche changed their story on PCCB the seem unwilling to admit that they made a mistake. One which those of us who paid a ridiculous price for the GT2 in the first place are condemned to pay for. Colm, please do not lose your files because I may want them in the near future. I see litigation brewing unless Porsche comes to their senses. I'd accept a conversion to steel rotors plus one replacement of the ceramic rotors as a fair deal. As others have suggested I'd store the PCCB and use the cheaper steel rotors for DE.
11-05-2003, 05:04 PM
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Sloth: In theory the front PCCB and steel/iron rotors are a direct swap. The rear is problematic as the PCCB and steel/iron rotors are different sizes so you'd also have to swap the calipers. There _may_ be a difference in ABS calibration but I haven't heard anything definite on that.