GT2 brakes (Ceramic) = useless
10-10-2003, 09:07 AM
#31
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Gerard: I think the comments of your engineer are generally correct. Heat abrosption, heat dissipation, and poor thermal conductitvity are right on.
Colm and Offroad, I think your logic is flawed. I am an engineer and have a reasonable understanding of brake systems, but instead of going technical, I will take a practical approach.
1. Why do almost all race cars use iron rotors? Certainly Nascar could use whatever they want and they use iron! They have much heavier cars with less cooling than F1 cars.
2. Porsche on all their cup cars uses iron. They could certainly afford ceramics and I guarantee you that when they are better, everyone will install them!
3. The Enzo brakes are carbon-ceramic and are very close to Formula 1 brakes and are absolutely outstanding. But then again, the pads alone cost around $5,000. No one has discussed the longetivity of the brakes but people who buy and Enzo expect ludicrous maintenance bills (I can vouch for this owing just a Lamborghini).
Now, I'm npot saying the ceramic brakes are bad, just not as good on the track as iron, - at this time.
Tim
Colm and Offroad, I think your logic is flawed. I am an engineer and have a reasonable understanding of brake systems, but instead of going technical, I will take a practical approach.
1. Why do almost all race cars use iron rotors? Certainly Nascar could use whatever they want and they use iron! They have much heavier cars with less cooling than F1 cars.
2. Porsche on all their cup cars uses iron. They could certainly afford ceramics and I guarantee you that when they are better, everyone will install them!
3. The Enzo brakes are carbon-ceramic and are very close to Formula 1 brakes and are absolutely outstanding. But then again, the pads alone cost around $5,000. No one has discussed the longetivity of the brakes but people who buy and Enzo expect ludicrous maintenance bills (I can vouch for this owing just a Lamborghini).
Now, I'm npot saying the ceramic brakes are bad, just not as good on the track as iron, - at this time.
Tim
10-10-2003, 09:10 AM
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PCCB Real Experience
I've read this thread and kept quiet, since I do not feel qualified to discuss the metallurgy or thermodynamic issues.
I purchased a GT2 earlier this year that was approximately 18months old and has done 9,000 miles. The car was equipped with the PCCB ceramic brakes.
Once I had started to acclimatise to the car I felt that the brakes were performing very poorly, worse than previous stock Porsches I had owned and in no way consistent with the great reviews they had got in the press.
By way of comparison I simultaneously owned this car with a genuine 993 RS 3.8 and a Nissan Skyline GTR R34 with 600+ rwhp and 10 pot brakes, so I am well used to speed, power and good brakes.
Upon examing the rotors and pads two things were clear:
1. The stock yellow pads had been replaced with black Pagid pads, which I would guess are race/track pads.
2. The front rotors were very badly damaged, with lots of surface degredation and small gouges out of the disc, where the disc almost looked like it was crumbling.
I contacted my Porsche Dealer to ask them to examine the brakes (I had purchased the car privately). They looked in detail and then summoned a brake expert from the Porsche HQ to examine and opine.
Their inital response was that due to the damage to the discs the car had been driven on track and that therefore the damage was to be expected, but would not be covered by warranty. After a brief conversation, when they became aware that the damage could not have been caused by me, due to only owning the car for a few weeks, they very kindly offered to replace the rotors and pads free as a goodwill gesture, for which I was obviously greatly relieved.
They made it clear to me that whilst the expectation was that in normal use the longevity of the discs was expected, if the car saw heavy track use, especially if the pads were changed to harder pads, then the rotors might have a very short life indeed (as would steel). They made it clear they would not provide another set of rotors under warranty or goodwill.
They also told me that the list price for a pair of rotors and pads was £14,000 ($22,400).
With the new rotors and the standard yellow pads the car now brakes very well indeed and has never faded once even in hard driving.
I would summarise the situation as follows for PCCB:
1. They work very well for a street car and will last.
2. They will not last if used for track or race and are very expensive to replace.
3. They represent a huge potential liability to owners in future.
4. They are great for the wheels as they shed almost no brake dust.
Whilst I am happy with them on my car as a road car and am very pleased with how Porsche have dealt with my problem, my view going forward is as follows:
1. If I was to order a new car, I would not choose PCCB, as the slight advantages do not outweight the dis-advantages and the potential liability.
2. If you have PCCB and plan to use the car on track, I suggest you remove the PCCB, store them very safely, put on a set of steel rotors (350mm or upgrade to 380mm), use the steel rotors as a low-cost replacable trackday rotor and replace the PCCB on the car come re-sale time.
There is a good reason that no Porsche race teams use the PCCB rotors -why is that? (I saw at least 20 GT3 race-cars at the 24hr Nurburgring race this year and none had PCCB)
Guy
I purchased a GT2 earlier this year that was approximately 18months old and has done 9,000 miles. The car was equipped with the PCCB ceramic brakes.
Once I had started to acclimatise to the car I felt that the brakes were performing very poorly, worse than previous stock Porsches I had owned and in no way consistent with the great reviews they had got in the press.
By way of comparison I simultaneously owned this car with a genuine 993 RS 3.8 and a Nissan Skyline GTR R34 with 600+ rwhp and 10 pot brakes, so I am well used to speed, power and good brakes.
Upon examing the rotors and pads two things were clear:
1. The stock yellow pads had been replaced with black Pagid pads, which I would guess are race/track pads.
2. The front rotors were very badly damaged, with lots of surface degredation and small gouges out of the disc, where the disc almost looked like it was crumbling.
I contacted my Porsche Dealer to ask them to examine the brakes (I had purchased the car privately). They looked in detail and then summoned a brake expert from the Porsche HQ to examine and opine.
Their inital response was that due to the damage to the discs the car had been driven on track and that therefore the damage was to be expected, but would not be covered by warranty. After a brief conversation, when they became aware that the damage could not have been caused by me, due to only owning the car for a few weeks, they very kindly offered to replace the rotors and pads free as a goodwill gesture, for which I was obviously greatly relieved.
They made it clear to me that whilst the expectation was that in normal use the longevity of the discs was expected, if the car saw heavy track use, especially if the pads were changed to harder pads, then the rotors might have a very short life indeed (as would steel). They made it clear they would not provide another set of rotors under warranty or goodwill.
They also told me that the list price for a pair of rotors and pads was £14,000 ($22,400).
With the new rotors and the standard yellow pads the car now brakes very well indeed and has never faded once even in hard driving.
I would summarise the situation as follows for PCCB:
1. They work very well for a street car and will last.
2. They will not last if used for track or race and are very expensive to replace.
3. They represent a huge potential liability to owners in future.
4. They are great for the wheels as they shed almost no brake dust.
Whilst I am happy with them on my car as a road car and am very pleased with how Porsche have dealt with my problem, my view going forward is as follows:
1. If I was to order a new car, I would not choose PCCB, as the slight advantages do not outweight the dis-advantages and the potential liability.
2. If you have PCCB and plan to use the car on track, I suggest you remove the PCCB, store them very safely, put on a set of steel rotors (350mm or upgrade to 380mm), use the steel rotors as a low-cost replacable trackday rotor and replace the PCCB on the car come re-sale time.
There is a good reason that no Porsche race teams use the PCCB rotors -why is that? (I saw at least 20 GT3 race-cars at the 24hr Nurburgring race this year and none had PCCB)
Guy
10-10-2003, 10:41 AM
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Please be aware that most Sports Car sanctioning bodies do not allow Ceramic brakes - thus one will not see them at most race events.
Perhaps I'm missing something, but the issue is not whether PCCB brakes are "better" (a highly subjective term), but whether or not they reliably and frequently meet the terms stated by Porsche in the sales literature.
At the Frankfurt show debut of PCCB on the stand, the following were claimed:
Outstanding life of the rotor (no word on pad life) in "All applications" (their words, not mine).
Reduced levels of brake dust/debris
Greatly reduced levels of fade over a number of brake applications (the chart provided at the show displays 25 stops of PCCB vs iron brakes).
To my mind, these statements have not been met at a very high level.
BTW, the literature also claims a "fully metallic pad" unique to PCCB. What happened to that pad?
J
Perhaps I'm missing something, but the issue is not whether PCCB brakes are "better" (a highly subjective term), but whether or not they reliably and frequently meet the terms stated by Porsche in the sales literature.
At the Frankfurt show debut of PCCB on the stand, the following were claimed:
Outstanding life of the rotor (no word on pad life) in "All applications" (their words, not mine).
Reduced levels of brake dust/debris
Greatly reduced levels of fade over a number of brake applications (the chart provided at the show displays 25 stops of PCCB vs iron brakes).
To my mind, these statements have not been met at a very high level.
BTW, the literature also claims a "fully metallic pad" unique to PCCB. What happened to that pad?
J
10-10-2003, 11:08 AM
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ColorChange,
NASCAR uses iron rotors because they're CHEAP!
NASCAR has developed a formula by which they run the business that calls for keeping the costs down. They theorize that low costs are necessary to promote entry of new teams at the grass-roots levels of their organization. They've gotten to the point where a manufacturer has to have products on NASCAR's "approved list" for teams to be able to use them on the track. One of the requirements for approval is that NASCAR must like the product -- for whatever reasons seem good to NASCAR.
NASCAR uses iron rotors because they're CHEAP!
NASCAR has developed a formula by which they run the business that calls for keeping the costs down. They theorize that low costs are necessary to promote entry of new teams at the grass-roots levels of their organization. They've gotten to the point where a manufacturer has to have products on NASCAR's "approved list" for teams to be able to use them on the track. One of the requirements for approval is that NASCAR must like the product -- for whatever reasons seem good to NASCAR.
10-10-2003, 11:08 AM
#36
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Originally posted by Colm
I'll put my trust in Porsche engineers any day...Come to think of it I do, everytime I drive. I think there's a whole more to this than a simplistic "marketing" answer.
I'll put my trust in Porsche engineers any day...Come to think of it I do, everytime I drive. I think there's a whole more to this than a simplistic "marketing" answer.
Pretty much your entire post comes down to this one quoted paragraph. Fair enough. Everyone is entitled to their opinion. But please excuse me if I'm not convinced.
On the other hand, everything that Gerard quoted does agree with my own experiences and with what I too have been told. I do find this much more convincing than blind faith.
Stephen
10-10-2003, 01:05 PM
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Guys,
This is a very interesting thread. I have learned a lot. In the last two seasons I did a total of 55 track days with my GT2. I have gone through three sets of pads, four sets of R compound tires and my PCCB perform very well as long as I follow2 basic rules. 1) Bed the pads properly. 2) Keep the holes in the rotors clean. Note that I use race tires which means that I can use my brakes more than a car on street tires. I've had poor (bad!) braking when I used pads which were not broken in enough. That sounds a lot the problem Gerard described at SPA. I have also had poor braking when the rotors holes were plugged. By following the rules above I have had outstanding braking performance even in a 90 minute eduro.
I suspect many of us are concerned that if we have a problem with rotors we will: a)be told that no warranty applies if they were used on the track; and b) face a huge cost to replace them.
With 25-30 track days per season, I normally replace rotors every two years. No big deal (for the steel ones) and I don't claim them under warranty. On the other hand, if I have to replace (at my cost) ceramic rotors every two years, I will be very upset with Porsche. On or off the track, these rotors must last longer than the cheap steel versions.
For Guy, the OEM pad for PCCB is a Pagid Yellow "Sport". Of interst to all, when you buy a new set you find a slip of paper in the box saying that said pads should not be used on the street. If Porsche tries to tell me that I wore out rotors prematurely by using yellow pads, I will remind them that the comes with them from the factory.
This is a very interesting thread. I have learned a lot. In the last two seasons I did a total of 55 track days with my GT2. I have gone through three sets of pads, four sets of R compound tires and my PCCB perform very well as long as I follow2 basic rules. 1) Bed the pads properly. 2) Keep the holes in the rotors clean. Note that I use race tires which means that I can use my brakes more than a car on street tires. I've had poor (bad!) braking when I used pads which were not broken in enough. That sounds a lot the problem Gerard described at SPA. I have also had poor braking when the rotors holes were plugged. By following the rules above I have had outstanding braking performance even in a 90 minute eduro.
I suspect many of us are concerned that if we have a problem with rotors we will: a)be told that no warranty applies if they were used on the track; and b) face a huge cost to replace them.
With 25-30 track days per season, I normally replace rotors every two years. No big deal (for the steel ones) and I don't claim them under warranty. On the other hand, if I have to replace (at my cost) ceramic rotors every two years, I will be very upset with Porsche. On or off the track, these rotors must last longer than the cheap steel versions.
For Guy, the OEM pad for PCCB is a Pagid Yellow "Sport". Of interst to all, when you buy a new set you find a slip of paper in the box saying that said pads should not be used on the street. If Porsche tries to tell me that I wore out rotors prematurely by using yellow pads, I will remind them that the comes with them from the factory.
10-10-2003, 01:12 PM
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Mike - I checked, but didn't know until then, that Nascar does have a restriciton requiring the use of iron rotors. I am sure they do this for advertising reasons, not cost as they spend millions on their race cars. The cost is not an issue, the advertising support and connection to fans is the issue until ceramics become more popular and common.
Nascar probalby could use ceramics now but they would throw them away after the race. We need more life out of our brakes and cannot afford to throw them away. This will probably be addressed in the future but from everything I am aware of, Prosche's ceramics aren't ready for racing yet, street driving .. sure, just not racing.
Nascar probalby could use ceramics now but they would throw them away after the race. We need more life out of our brakes and cannot afford to throw them away. This will probably be addressed in the future but from everything I am aware of, Prosche's ceramics aren't ready for racing yet, street driving .. sure, just not racing.
10-10-2003, 01:23 PM
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Color,
Most race series mandate the use of iron rotors inlcuding NASCAR. They are not targeting PCCB so much as "real" carbon brakes as used in Formula One. This is to prevent well financed teams from winning by outspending the rest. You'll find steel rotors mandated in Rolex, and Grand Am racing for the same reason. The idea is to keep the costs manageable for the "little guys". If racers could use ceramic or carbon fiber brakes they would - at least those who could afford them. There are lots of oother rules which preclude the use of exotic materials in a race car for the same reason. In F-1 things are different.
Cheers,
Most race series mandate the use of iron rotors inlcuding NASCAR. They are not targeting PCCB so much as "real" carbon brakes as used in Formula One. This is to prevent well financed teams from winning by outspending the rest. You'll find steel rotors mandated in Rolex, and Grand Am racing for the same reason. The idea is to keep the costs manageable for the "little guys". If racers could use ceramic or carbon fiber brakes they would - at least those who could afford them. There are lots of oother rules which preclude the use of exotic materials in a race car for the same reason. In F-1 things are different.
Cheers,
10-10-2003, 01:37 PM
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Bob - I have not run the ceramics so I can only go by what others say. You are probably the strongest person who has run them and hard and had good things to say. Others have had various problems.
I didn't order them for my car because they are quite expensive when the Brembo LeMans is highly proven and I'm sure quite comparable in performance, with much lower maintenance costs. I think the Brembo's are the better choice.
Bob - what do you think?
Tim
I didn't order them for my car because they are quite expensive when the Brembo LeMans is highly proven and I'm sure quite comparable in performance, with much lower maintenance costs. I think the Brembo's are the better choice.
Bob - what do you think?
Tim
10-10-2003, 03:37 PM
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Guy R
You state the following:
Upon examing the rotors and pads two things were clear:
1. The stock yellow pads had been replaced with black Pagid pads, which I would guess are race/track pads.
2. The front rotors were very badly damaged, with lots of surface degredation and small gouges out of the disc, where the disc almost looked like it was crumbling.
I think this may have been the source of your damage (the black pads used on the track)
From what I have gathered you can use yellow (limited use) on the track ,DE etc, but for heavy track use you should use the green (PS 50). Nobody has ever mentioned or suggested using the black (comfort?) pads on the track.
Maybe Porsche is right after all!
You state the following:
Upon examing the rotors and pads two things were clear:
1. The stock yellow pads had been replaced with black Pagid pads, which I would guess are race/track pads.
2. The front rotors were very badly damaged, with lots of surface degredation and small gouges out of the disc, where the disc almost looked like it was crumbling.
I think this may have been the source of your damage (the black pads used on the track)
From what I have gathered you can use yellow (limited use) on the track ,DE etc, but for heavy track use you should use the green (PS 50). Nobody has ever mentioned or suggested using the black (comfort?) pads on the track.
Maybe Porsche is right after all!
10-10-2003, 03:58 PM
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bob-
i lifted this from your post over on gt3:
"There are also issues surfacing with the steel rotors on the GT3. There are five who track them in this region (more coming) and two have had problems of surface cracks on the rotors after a 2 day event (that's about 4 hours of total track time) and cracks in the brake pads"
guys, do we draw the conclusion from this that 40% of iron rotors fail on the track and now we should buy pccb???
the issue is pccb rotors are expensive.
i lifted this from your post over on gt3:
"There are also issues surfacing with the steel rotors on the GT3. There are five who track them in this region (more coming) and two have had problems of surface cracks on the rotors after a 2 day event (that's about 4 hours of total track time) and cracks in the brake pads"
guys, do we draw the conclusion from this that 40% of iron rotors fail on the track and now we should buy pccb???
the issue is pccb rotors are expensive.
10-10-2003, 04:00 PM
#43
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IN September 2001 Porsche issued a technical bulletin to dealers which said that the Comfort (Black) pads should never be used on the track. My dealer didn't know this. I asked for replacement pads and got the black ones. At the track they failed in catastrophic fashion. When they get very hot the black comfort pads will crumble when they cool down. This happened to me. When I say crumble, I mean disintegrate. This left me with no pads at all and when I hit the brakes, I got a warning light, a horrible metal to metal grinding sound and little to no braking. This damaged the front rotors which were replaced by the dealer for free. At the time, there were no sport pads in North America. Dealers had only the comfort pad in stock. I got mine from Motorsport. Colm may be onto the reason for Guy's mangled rotors.
10-10-2003, 05:31 PM
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ColorChange,
"I am sure they do this for advertising reasons, not cost as they spend millions on their race cars. The cost is not an issue, the advertising support and connection to fans is the issue until ceramics become more popular and common. "
Your interpretation has some plausibility. My post was merely a recitation of what the NASCAR chief steward told me while I was present in the paddock for the Watkins Glen road course race back in the late '80s.
I was complaining to him that in-car data recorders (banned at that point) would go a long way toward making teams more competitive. That's when I got the "cost" lecture.
"I am sure they do this for advertising reasons, not cost as they spend millions on their race cars. The cost is not an issue, the advertising support and connection to fans is the issue until ceramics become more popular and common. "
Your interpretation has some plausibility. My post was merely a recitation of what the NASCAR chief steward told me while I was present in the paddock for the Watkins Glen road course race back in the late '80s.
I was complaining to him that in-car data recorders (banned at that point) would go a long way toward making teams more competitive. That's when I got the "cost" lecture.
10-10-2003, 06:54 PM
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Thanks guys, you may be onto something, I'll check the black pads that are still on the rear to see if there are any numbers or markings.
I've requested a new set of rear pads in yellow to match the front which they are ordering from Germany (no PCCB pads or rotors are kept in stock in the UK as there is no demand for spares). The dealer said that the Porsche Order system said there were two types available , Comfort and 'Normal' (which we are assuming is the yellow sport).
Once I am on yellows all round I'll see how it goes.
I'll keep you updated.
Guy
I've requested a new set of rear pads in yellow to match the front which they are ordering from Germany (no PCCB pads or rotors are kept in stock in the UK as there is no demand for spares). The dealer said that the Porsche Order system said there were two types available , Comfort and 'Normal' (which we are assuming is the yellow sport).
Once I am on yellows all round I'll see how it goes.
I'll keep you updated.
Guy