GT2 brakes (Ceramic) = useless
10-01-2003, 01:29 PM
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GT2 brakes (Ceramic) = useless
I live in Europe and have owned a bunch of Porsches up until now, including a 911 Turbo of every type (except 3.0) and a RUF in the process. I now own a 996 TT (1 month old), which I knew would get souped up in power etc. The cars always stood out for braking and turbo kick. I hesitated to take the Ceramic brakes, and at the end didn't for timing reasons on my delivery.
I have just driven a 996 GT2 on the track, and man am I happy I didn't fork out the extra cash!!!! The brakes lasted exactly 4 laps around Spa. I will do around 2:45 in my TVR racer around Spa, which for an am is a decent time, thus I wasn't driving slow with the GT2, but 4 laps for a brake system that is supposed to last for ever!!!! So on the phone I get with the owner, and we talk to a brake engineer, who tells me that the factory has received numeruous legal claims by GT2/996TT owners having to swap back to different brakes!!! Apparently Ceramic disks unlike carbon (huge difference), are isolators and thus do not provide the adequate reaction to heat, they also tend to brake apart. From the engineer, I understand that the factory tests were not exactly "great" but that for marketing reasons it was decided to go ahead nevertheless.
I find this amazing, and was just curious to find out whether this is a European disease or something that you guys in the US encounter too.
Cheers,
Gerard
I have just driven a 996 GT2 on the track, and man am I happy I didn't fork out the extra cash!!!! The brakes lasted exactly 4 laps around Spa. I will do around 2:45 in my TVR racer around Spa, which for an am is a decent time, thus I wasn't driving slow with the GT2, but 4 laps for a brake system that is supposed to last for ever!!!! So on the phone I get with the owner, and we talk to a brake engineer, who tells me that the factory has received numeruous legal claims by GT2/996TT owners having to swap back to different brakes!!! Apparently Ceramic disks unlike carbon (huge difference), are isolators and thus do not provide the adequate reaction to heat, they also tend to brake apart. From the engineer, I understand that the factory tests were not exactly "great" but that for marketing reasons it was decided to go ahead nevertheless.
I find this amazing, and was just curious to find out whether this is a European disease or something that you guys in the US encounter too.
Cheers,
Gerard
10-01-2003, 08:57 PM
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Over 4000 miles, on track and off, PCCB equiped GT2, no problems whatsoever. These threads do make me nervous, though.
Does anyone have any REAL evidence (semi-official reports, statements by Porsche, statements by reputable sources, articles in major car magazines, etc.)? My scientific background leads me to discount heavily anecdotal information (which is all I have heard so far).
Is this the vocal minority we are hearing from, or is there actually a problem with the ceramic brake system? If so, I imagine Porsche is in big trouble....
I bought a 1995 BMW 540i that was a victim of the Nikasil engine block problem. I remember there were so many myths, misunderstandings and misinformations circulating at the time the problem emerged. BMW finally admitted (in 1997) that there was an issue, and extended our warranties to 100k miles.
Does anyone have any REAL evidence (semi-official reports, statements by Porsche, statements by reputable sources, articles in major car magazines, etc.)? My scientific background leads me to discount heavily anecdotal information (which is all I have heard so far).
Is this the vocal minority we are hearing from, or is there actually a problem with the ceramic brake system? If so, I imagine Porsche is in big trouble....
I bought a 1995 BMW 540i that was a victim of the Nikasil engine block problem. I remember there were so many myths, misunderstandings and misinformations circulating at the time the problem emerged. BMW finally admitted (in 1997) that there was an issue, and extended our warranties to 100k miles.
10-02-2003, 12:29 AM
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Do people who upgrade with steel discs have fade problems? I understand the unsprung weight issue, but the purchase price seems steep for solving a non-existent problem. AS
10-02-2003, 09:55 AM
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Re: GT2 brakes (Ceramic) = useless
Originally posted by gl911
we talk to a brake engineer, who tells me that the factory has received numeruous legal claims by GT2/996TT owners having to swap back to different brakes!!!
we talk to a brake engineer, who tells me that the factory has received numeruous legal claims by GT2/996TT owners having to swap back to different brakes!!!
Can you be any more specific about this? Was the brake engineer affiliated with Porsche? The legal claims were lawsuits or just threats?
I'm at that point now where I'm threatening litigation if they don't put back the original system. Any information you can give me would be useful.
off list if you prefer: lists@indocap.com.
Thanx.
Stephen
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10-02-2003, 05:50 PM
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The info about me driving the car and the brakes fading is first hand, and easily explained due to the fact that the ceramic brakes do not do an efficient job at releasing the tremenduous heat generated and thus that is transferred into the braking liquid which starts boiling, creates air bubbles and thus provides the fading by not having the adequate presssure. Again I experienced this after 4 laps of Spa Francorchamps with Michelin Cup tires and around 22 degrees celsius (not too hot)
The engineer (doesn't want to be swamped with mail or calls) I refer too is extremely knowledgable about this as he is known as one of the braking gurus world wide, consults for MB, Nissan Motorsport, Honda in the Japanese GT series etc. as well as the company that provides most of the braking components to Porsche and other brands. The lawsuits are according to him just that and not simple threats. As far as the change of brakes goes, most of those people have opted for other stuff but always steel.
The fact that the ceramic brakes have been pushed by the marketing department is not a myth. MB used the same technology on the CL 55 F1 series, and decided to take the brakes back. Now this CL 55 in 2000 had 347 HP, how come the 500 HP CL now has steel brakes?
Finally and even more funnily, Brembo who also delivers the brakes for MB has a special deal for the top of the line S-Class. If any of you guys have an S Class (I did), check the following, the brake calipers are from the "old" turbo that is the 1989 Turbo 3.3, while the disks vented and perforated don't work, because one rotates correctly letting air out, while the other rotates in the wrong direction holding the hot air in. Why? Because it was cheaper to cast a single disk, rather than having an actual left and right. Check it out it is funny, next time you see an S Class. Thus it is not just Porsche who plays tricks on us with some fancy wording/pictures out of the marketing depts.
So much to the braking debate. I am happy to share more war stories, as this is a topic that I have always taken seriously. Just ask Chrysler about my own adventure regarding my initial Viper GTSs brakes
Gerard
The engineer (doesn't want to be swamped with mail or calls) I refer too is extremely knowledgable about this as he is known as one of the braking gurus world wide, consults for MB, Nissan Motorsport, Honda in the Japanese GT series etc. as well as the company that provides most of the braking components to Porsche and other brands. The lawsuits are according to him just that and not simple threats. As far as the change of brakes goes, most of those people have opted for other stuff but always steel.
The fact that the ceramic brakes have been pushed by the marketing department is not a myth. MB used the same technology on the CL 55 F1 series, and decided to take the brakes back. Now this CL 55 in 2000 had 347 HP, how come the 500 HP CL now has steel brakes?
Finally and even more funnily, Brembo who also delivers the brakes for MB has a special deal for the top of the line S-Class. If any of you guys have an S Class (I did), check the following, the brake calipers are from the "old" turbo that is the 1989 Turbo 3.3, while the disks vented and perforated don't work, because one rotates correctly letting air out, while the other rotates in the wrong direction holding the hot air in. Why? Because it was cheaper to cast a single disk, rather than having an actual left and right. Check it out it is funny, next time you see an S Class. Thus it is not just Porsche who plays tricks on us with some fancy wording/pictures out of the marketing depts.
So much to the braking debate. I am happy to share more war stories, as this is a topic that I have always taken seriously. Just ask Chrysler about my own adventure regarding my initial Viper GTSs brakes
Gerard
10-02-2003, 05:57 PM
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By the way, one of the reasons ceramic brakes do not do a good job at dissipating heat, is also because the pads are much more aggressive and thus create even more heat to start with. I'll share any other finding as we investigate on my friends GT2 and with the factory.
10-03-2003, 08:37 AM
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Originally posted by gl911
The info about me driving the car and the brakes fading is first hand, and easily explained due to the fact that the ceramic brakes do not do an efficient job at releasing the tremenduous heat generated and thus that is transferred into the braking liquid which starts boiling, creates air bubbles and thus provides the fading by not having the adequate presssure. Again I experienced this after 4 laps of Spa Francorchamps with Michelin Cup tires and around 22 degrees celsius (not too hot)
The info about me driving the car and the brakes fading is first hand, and easily explained due to the fact that the ceramic brakes do not do an efficient job at releasing the tremenduous heat generated and thus that is transferred into the braking liquid which starts boiling, creates air bubbles and thus provides the fading by not having the adequate presssure. Again I experienced this after 4 laps of Spa Francorchamps with Michelin Cup tires and around 22 degrees celsius (not too hot)
Technically, boiled fluid isn't considered "brake fade". Brake fade is when the pad material overheats to such an extent that there is no more friction between the pads and the rotors. Boiled fluid means you cannot deliver the pressure to the pads to work the brakes.
For what it is worth, my experience and the experience of others is that the boiled fluid problem can be totally dealt with by swapping to a high temp DOT4 fluid (my recommendation is Castrol SRF).
One of the reasons that the rotors and pads destroy themselves is that they do not fade. Fade would force the driver to back off. Since they don't fade, he is able to get them hotter and hotter until they destroy themselves.
I really would appreciate info on the lawsuits. I would like to contact the parties or their lawyers.
Stephen
10-03-2003, 12:08 PM
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Last weekend, there was a GT2 at Laguna. The driver was quite experienced and was pushing his car to its limit in the fast group. He was braking really hard and really late all the time. He was using green "race" pads with his ceramic rotors and so far was happy with the setup. He was very fast, running at the same speed than a few Radical SR3. Additionally, he was running with some slicks.
My own conclusion on this topic, is that the street pads have been designed to optimize for the rotor life. They generate a lot of heat. When the pad is too hot, it won't grab. I have experienced this with my car. It is not a brake fade as the pedal does not go to the floor. The pad simply does not grab, or more exactly, does not stop the rotor as efficiently as usual. At that point, I suspect it is necessary to back off and cool the rotors. If not, there is a risk to destroy the rotors.
Race pads should be used on the track. They can be obtained via your Porsche dealer (I bought a set last week). I haven't tried them yet but suspect they are not as good the street pads when cold and are likely harder on the rotors from a longevity point of view.
AW
My own conclusion on this topic, is that the street pads have been designed to optimize for the rotor life. They generate a lot of heat. When the pad is too hot, it won't grab. I have experienced this with my car. It is not a brake fade as the pedal does not go to the floor. The pad simply does not grab, or more exactly, does not stop the rotor as efficiently as usual. At that point, I suspect it is necessary to back off and cool the rotors. If not, there is a risk to destroy the rotors.
Race pads should be used on the track. They can be obtained via your Porsche dealer (I bought a set last week). I haven't tried them yet but suspect they are not as good the street pads when cold and are likely harder on the rotors from a longevity point of view.
AW
10-03-2003, 03:25 PM
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I will post the findings from the factory as soon as we have an official answer, and if he permits I will also post the contact to the engineer, if I do please avoid mail swamping him.
Gerard
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10-03-2003, 05:37 PM
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gerard,
your comments on S600 would cover 2001 cars? my wife has one, i will look at the rotors.
on pccb,
i now have 14,000 miles on pccb. no issues except occasional mild screech, and poor cold braking. i have whatever pad is stock currently with 7000 miles on this gt2. i find my brakes must warm up for 20 minutes or more and then they become wonderbar. they are poor when cold, as i find every morning.
there's enough smoke for there to be a fire somewhere. i have said before that rick perkins my exec at PCNA has only had one claim when we spoke about it a month ago. if i ever do have problems i know he'll replace them, he's always been fair to me the last 15 years over many cars and many problems. i do admit the factory sounds less accommodating in Europe.
your comments on S600 would cover 2001 cars? my wife has one, i will look at the rotors.
on pccb,
i now have 14,000 miles on pccb. no issues except occasional mild screech, and poor cold braking. i have whatever pad is stock currently with 7000 miles on this gt2. i find my brakes must warm up for 20 minutes or more and then they become wonderbar. they are poor when cold, as i find every morning.
there's enough smoke for there to be a fire somewhere. i have said before that rick perkins my exec at PCNA has only had one claim when we spoke about it a month ago. if i ever do have problems i know he'll replace them, he's always been fair to me the last 15 years over many cars and many problems. i do admit the factory sounds less accommodating in Europe.
10-04-2003, 11:43 AM
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I had a problem with my PCCB using the black "comfort pads" on the track. They heat up and when they cool down they break apart. Porsche issued a tech bulletin in Sept -01 saying never to used comfort pads on the track. I guess my dealer was behind in his reading because they gave me the softer comfort pads. Using the yellow "Sport" pads I have had no problems on the track. I do wonder about the long term though since new rotors cost a fortune. I have read that the 2004 cars have an improved version of the rotors. Like everone else reading this thread I'd like to know more. Gert Carnewal mentioned that some guys in Europe were switching to the steel rotors from the GT3. Let's all keep digging.
Bob
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10-04-2003, 01:56 PM
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Originally posted by FixedWing
Gerard,
Technically, boiled fluid isn't considered "brake fade". Brake fade is when the pad material overheats to such an extent that there is no more friction between the pads and the rotors. Boiled fluid means you cannot deliver the pressure to the pads to work the brakes.
Gerard,
Technically, boiled fluid isn't considered "brake fade". Brake fade is when the pad material overheats to such an extent that there is no more friction between the pads and the rotors. Boiled fluid means you cannot deliver the pressure to the pads to work the brakes.
1) Pad Fade - occurs for several reasons. All friction material (brake pad stuff) has a coefficient of friction curve over temperature. Friction materials have an optimal working temperature where the coefficient of friction is the highest. Sometimes you can use the brakes so hard that you get the temperature over the point of maximum friction to where the coefficient of friction curve starts to decline.
2) Green Fade - fade that manifests itself on brand new brake pads. Brake pads are usually made of different types of heat resistant materials bound together with a phenolic resin binder. These are thermosetting plastic resins with a high heat resistance. On a new brake pad, these resins will out-gas or cure when used hard on their first few heat cycles. The new pad can hydroplane on this layer of excreted gas.
3) Fluid fade - caused by the boiling of the brake fluid in the calipers. This produces bubbles in the brake system. Since bubbles are compressible, this makes for a soft spongy pedal.
Please correct me if I am mis-informed. Thanks
