Carbon Brakes - walk away or worth it?
Discussion
Harris_I said:
Hallelujah! Our brother has seen the light.
For everyone else who enjoys blowing a wad of cash on a nice caliper paint job, here are some tips:
1. Listen carefully to everything the OPC salesman tells you. He is a member of MENSA and font of all knowledge. Especially on brakes.
2. Ignore advice from race teams and their drivers and dismiss any telemetry data as the mad rantings of ignorant halfwits.
3. Scientific fact is impotent in the face of the Cult of Carbon Ceramic. Revel joyfully in the knowledge thou art chosen. For OEM part numbers 997.351.409.92 and 997.351.410.92 are the numbers of the Beast. Worship the Yellow Caliper. Wear the Porsche Design Martini Racing Jacket and matching driving shoes with pride.
4. Venerate the sacred texts and commit them to memory. For the Book of evo, the Book of CAR and the Book of AutoCar shall become thy guidance and comfort. Their clerics shall be the high priests of our cult, and shall suffer no temptation or freebie junkets to the Algarve.
5. Ignore long forum threads on the subject. For the unbelievers shall have posted many times before and their silence may be assured through sheer force of numbers.
Excellent For everyone else who enjoys blowing a wad of cash on a nice caliper paint job, here are some tips:
1. Listen carefully to everything the OPC salesman tells you. He is a member of MENSA and font of all knowledge. Especially on brakes.
2. Ignore advice from race teams and their drivers and dismiss any telemetry data as the mad rantings of ignorant halfwits.
3. Scientific fact is impotent in the face of the Cult of Carbon Ceramic. Revel joyfully in the knowledge thou art chosen. For OEM part numbers 997.351.409.92 and 997.351.410.92 are the numbers of the Beast. Worship the Yellow Caliper. Wear the Porsche Design Martini Racing Jacket and matching driving shoes with pride.
4. Venerate the sacred texts and commit them to memory. For the Book of evo, the Book of CAR and the Book of AutoCar shall become thy guidance and comfort. Their clerics shall be the high priests of our cult, and shall suffer no temptation or freebie junkets to the Algarve.
5. Ignore long forum threads on the subject. For the unbelievers shall have posted many times before and their silence may be assured through sheer force of numbers.
An interesting thread, cannot believe people are quoting the Porsche marketing guff as conclusive proof of anything (even if I am in the pro-PCCB on 2nd hand cars not new camp)
Actually that might have been funny if the whole of my statement was taken into account.
I'm in my office this week so intend to get hold of someone from Porsche or the people who make them and forward this thread to see if they care to respond.
Quite some time ago I started a thread about PCCB's which didn't degenerate into a playground spat and on the whole did actually inform me and hopefully others about them which for some reason is what I thought enthusiasts forums were for.
I'm in my office this week so intend to get hold of someone from Porsche or the people who make them and forward this thread to see if they care to respond.
Quite some time ago I started a thread about PCCB's which didn't degenerate into a playground spat and on the whole did actually inform me and hopefully others about them which for some reason is what I thought enthusiasts forums were for.
Edited by BIRMA on Monday 23 June 13:29
BIRMA said:
I'm in my office this week so intend to get hold of someone from Porsche or the people who make them and forward this thread to see if they care to respond.
Really, don't bother. Porsche is now just another global branding exercise. To the gullible mass market they sell shoes and sunglasses, to the more wealthy they sell PCCB and cross-stitching. I'm glad they failed at Le Mans. They don't deserve it.Your answer is right here if you care to look for it.
I'm late to this party, and I'm afraid I'm a man of the arts rather then the sciences, so the maths goes over my head.
However, I currently own a GT3 with PCCBs. Before that, I owned a GT3 with steel discs. I can tell you that both stopped equally well once up to temp, despite the newer car being fitted with the fancy brakes (997 vs 996).
Furthermore, the PCCBs will often fade on track unless properly warmed up, whereas the steel discs in the 996 were nothing short of mesmerising in their ability to haul the car to a stop. With the 997, the brakes have to be coaxed before they will perform their best. This can be frustrating (they take a long time to reach optimum operating temp) and in most cases, down right frightening!
The PPCB equipped car does ride better however. That weight saving can be felt instantly, and of course there's the cosmetic advantages as well (not that I'm particularly bothered).
Were I ordering from new though, I'd leave the PCCB box unticked. I think Carbon discs are only of significant benefit at top level Motorsport where costs are irrelevant and the better heat dissipation and lighter weight actually can be felt in lap times. Alternatively, where money is irrelevant on a road car purchase, then knock yourself out.
My GT3 isn't tracked enough for the PCCBs to be a worry. And frankly, I have better things to spend my money on than £3k for replacement steel discs and pads. For the use it gets therefore, the PCCBs are fine, but vanity aside, I'd be more comfortable if they were steel.
I recently read a thread on Rennlist where some cleverer people than I compared the compound of the PCCB pads to to that of the equivalent steel brakes (997 RS) and additionally, to that of the popular Pagid RS29 track pad. The conclusion was that the PCCB pads are made of a particularly gentle compound so as to protect the surface of the disc; where a more abrasive race compound would drastically shorten the life of these 'lifetime' discs. It made for fascinating reading and confirmed my suspicions all along: that PCCB is a marketing exercise first and foremost and a technical solution second.
Hands up who is surprised by this...
However, I currently own a GT3 with PCCBs. Before that, I owned a GT3 with steel discs. I can tell you that both stopped equally well once up to temp, despite the newer car being fitted with the fancy brakes (997 vs 996).
Furthermore, the PCCBs will often fade on track unless properly warmed up, whereas the steel discs in the 996 were nothing short of mesmerising in their ability to haul the car to a stop. With the 997, the brakes have to be coaxed before they will perform their best. This can be frustrating (they take a long time to reach optimum operating temp) and in most cases, down right frightening!
The PPCB equipped car does ride better however. That weight saving can be felt instantly, and of course there's the cosmetic advantages as well (not that I'm particularly bothered).
Were I ordering from new though, I'd leave the PCCB box unticked. I think Carbon discs are only of significant benefit at top level Motorsport where costs are irrelevant and the better heat dissipation and lighter weight actually can be felt in lap times. Alternatively, where money is irrelevant on a road car purchase, then knock yourself out.
My GT3 isn't tracked enough for the PCCBs to be a worry. And frankly, I have better things to spend my money on than £3k for replacement steel discs and pads. For the use it gets therefore, the PCCBs are fine, but vanity aside, I'd be more comfortable if they were steel.
I recently read a thread on Rennlist where some cleverer people than I compared the compound of the PCCB pads to to that of the equivalent steel brakes (997 RS) and additionally, to that of the popular Pagid RS29 track pad. The conclusion was that the PCCB pads are made of a particularly gentle compound so as to protect the surface of the disc; where a more abrasive race compound would drastically shorten the life of these 'lifetime' discs. It made for fascinating reading and confirmed my suspicions all along: that PCCB is a marketing exercise first and foremost and a technical solution second.
Hands up who is surprised by this...
Koln-RS said:
I'd be surprised.
But maybe someone should tell Ferrari, Lamborghini, McLaren, Aston Martin, Bugatti, Zonda, etc, etc, that someone on pistonheads reckons carbon ceramic brakes are just a marketing wheeze
With the first Memo clearly going to your good self But maybe someone should tell Ferrari, Lamborghini, McLaren, Aston Martin, Bugatti, Zonda, etc, etc, that someone on pistonheads reckons carbon ceramic brakes are just a marketing wheeze
If you wanted further proof, why not phone those lovely chaps down at Ferrari and ask them when they recommend you should replace your carbon ceramic discs born from #racingtechnology.
Steve Rance said:
If I could find the extra budget to run ceramics in - say, British GT - I'd spend it on more tyres, shockers, aero, upgrading motec, and lots of other areas before I'd look at Ceramic brakes. Much bigger marginal gains to be had elsewhere.
Careful there Steve, we wouldn't want actual experience to get in the way of an internet argument...GreatPretender said:
Steve Rance said:
If I could find the extra budget to run ceramics in - say, British GT - I'd spend it on more tyres, shockers, aero, upgrading motec, and lots of other areas before I'd look at Ceramic brakes. Much bigger marginal gains to be had elsewhere.
Careful there Steve, we wouldn't want actual experience to get in the way of an internet argument...Anyway this afternoon I sent a number of polite, concise e-mails to a number of people in the vain hope that I may get a response worthy of further reasoned debate so I'll wait and see.
Perhaps the cynic in me whispers 'don't hold your breath' but let's wait and see.
It became obvious to me that Carbon brakes are not the first choice of many people on this thread who are doing a lot of track work, but in all honesty until the big playground spat kicked off the original post was about a road car and most of the discussion was about their use in road cars.
BIRMA said:
I would just like to say that everything on this subject I have written is based on actual experience be it limited regarding going on track
And here lies the problem. A driver's "very late braking" is another driver's confidence lift...Please don't go defensive, this is an honest and straight comment based on my own (limited compared to most genuine track pedalers) 15 years track/motorsport experience.
Edited by nickfrog on Monday 23 June 18:56
Heres a graph from an independent brake test done on various cars. Of interest here of course is the 911 with and without PCCB. 350mm PCCB with 6 pots, 330mm Steels with 4 pots IIRC.
Each cycle contains 5 brake stops from 100mph - 0mph with 20 second gaps between the stops.
The first stop in each cycle was done using approx half brake force (0.5G) to measure pedal and the next 4 stops were done with maximum braking force (hence the panic stop label) from 100mph to 0 mph to complete that cycle.
This complete cycle was then repeated until fade presented itself (or i presume boredom kicked in in the case of the Porsches and Corvette).
You will note that the Steel and PCCB cars perform the same and without fade even after almost 50 repeat stops. You can see the BMW progressively loses its brakes from 4th cycle onwards and the Nismo Z hits full fade midway through cycle 3. I believe the Porsches were on Pirelli P Zero, the Vette on Goodyear Eagle.
For the science side, i already posted the equation for stopping distance earlier along with the info that for a street car 1-1.1G was about max possible sustained deceleration. If you go back a few pages and look at the deceleration G values on the test sheets of various Porsches you can see this verified across the test data too.
If you are interested in how the measured distances in the test faired relative to the theoretical:
At 1G, ie 9.81m/s^2
The calculated distance at 100mph = 44.704 x 44.704 / 2 x 9.81 = 101.86m or 334ft.
at 1.1G, ie 10.79m/s^2
The calculated distance at 100mph = 92.6m or 304ft.
What is also of interest (for those that don't work with maths, if you do you will have already seen this without needing results) is how sensitive the calculated distance is to small changes in speed. Using the 1.1G deceleration.
distance at 99mph = 90.8m or 297.8ft
distance at 100mph = 92.6m or 304ft
distance at 101mph = 94.5m or 309ft
distance at 102mph = 96.4m or 316ft
This sensitivity along with naturally varying reaction time and the small changes in tyre mu with each stop are the probable explanation of the variations seen in each stop and cycle. Its not a perfect test and this why the line has peaks and troughs. If one looks back at the various car test data sheets I posted earlier for various Porsches one will see the same thing.
Each cycle contains 5 brake stops from 100mph - 0mph with 20 second gaps between the stops.
The first stop in each cycle was done using approx half brake force (0.5G) to measure pedal and the next 4 stops were done with maximum braking force (hence the panic stop label) from 100mph to 0 mph to complete that cycle.
This complete cycle was then repeated until fade presented itself (or i presume boredom kicked in in the case of the Porsches and Corvette).
You will note that the Steel and PCCB cars perform the same and without fade even after almost 50 repeat stops. You can see the BMW progressively loses its brakes from 4th cycle onwards and the Nismo Z hits full fade midway through cycle 3. I believe the Porsches were on Pirelli P Zero, the Vette on Goodyear Eagle.
For the science side, i already posted the equation for stopping distance earlier along with the info that for a street car 1-1.1G was about max possible sustained deceleration. If you go back a few pages and look at the deceleration G values on the test sheets of various Porsches you can see this verified across the test data too.
If you are interested in how the measured distances in the test faired relative to the theoretical:
At 1G, ie 9.81m/s^2
The calculated distance at 100mph = 44.704 x 44.704 / 2 x 9.81 = 101.86m or 334ft.
at 1.1G, ie 10.79m/s^2
The calculated distance at 100mph = 92.6m or 304ft.
What is also of interest (for those that don't work with maths, if you do you will have already seen this without needing results) is how sensitive the calculated distance is to small changes in speed. Using the 1.1G deceleration.
distance at 99mph = 90.8m or 297.8ft
distance at 100mph = 92.6m or 304ft
distance at 101mph = 94.5m or 309ft
distance at 102mph = 96.4m or 316ft
This sensitivity along with naturally varying reaction time and the small changes in tyre mu with each stop are the probable explanation of the variations seen in each stop and cycle. Its not a perfect test and this why the line has peaks and troughs. If one looks back at the various car test data sheets I posted earlier for various Porsches one will see the same thing.
Edited by fioran0 on Monday 23 June 21:17
GreatPretender said:
Furthermore, the PCCBs will often fade on track unless properly warmed up, whereas the steel discs in the 996 were nothing short of mesmerising in their ability to haul the car to a stop. With the 997, the brakes have to be coaxed before they will perform their best. This can be frustrating (they take a long time to reach optimum operating temp) and in most cases, down right frightening!
That's really interesting stuff, thank you. It confirms my own observations of the steel discs set up on a 997 turbo at the Ring last year : no fade, despite the weight.So if the ceramics are hard to warm up on track, they must be even harder to warm up on the road presumably ?
nickfrog said:
GreatPretender said:
Furthermore, the PCCBs will often fade on track unless properly warmed up, whereas the steel discs in the 996 were nothing short of mesmerising in their ability to haul the car to a stop. With the 997, the brakes have to be coaxed before they will perform their best. This can be frustrating (they take a long time to reach optimum operating temp) and in most cases, down right frightening!
That's really interesting stuff, thank you. It confirms my own observations of the steel discs set up on a 997 turbo at the Ring last year : no fade, despite the weight.So if the ceramics are hard to warm up on track, they must be even harder to warm up on the road presumably ?
t' was when I wash the car they do need to have what I can only conclude is the water dispersed/evaporated before the usual confident feel of the brakes resumesfioranO the graph is excellent and throughout this thread you have in my opinion been spot on. I still don't think I'll change my braking habits as one the ABS has yet to kick in.
So do you guys think winter tyres are a good thing?
Edited by BIRMA on Monday 23 June 19:40
Edited by BIRMA on Monday 23 June 19:41
Edited by BIRMA on Monday 23 June 19:43
Modern ABS is now very advanced. It's no longer just a pulsating pedal.
They use preemptive as well as intervention strategies so are involved even during what appears to be normal braking and are usually way out ahead of the driver.
One example is bias adjustment which is carried out automatically by the ABS module. If you were to run brake pressure sensors you would see the ABS spike then bleed out rear pressure during braking, moving bias forwards as it goes. All this happens automatically and the driver is oblivious to any of this from the pedal.
ABS requires some specific strategies to get the most out of it on track, along with an understanding of its failure modes (ice mode for example) so that one is prepared and knows what to do if it occurs.
They use preemptive as well as intervention strategies so are involved even during what appears to be normal braking and are usually way out ahead of the driver.
One example is bias adjustment which is carried out automatically by the ABS module. If you were to run brake pressure sensors you would see the ABS spike then bleed out rear pressure during braking, moving bias forwards as it goes. All this happens automatically and the driver is oblivious to any of this from the pedal.
ABS requires some specific strategies to get the most out of it on track, along with an understanding of its failure modes (ice mode for example) so that one is prepared and knows what to do if it occurs.
Edited by fioran0 on Monday 23 June 21:19
ABS is almost always doing something, particularly with pressures. It's only when you get into a proper mess and its intervention strategies kick in that you start to get things like the pedal pulses that everyone thinks of when they think of ABS.
The rest of the time no one really notices as it gets about its work quietly.
If you are interested, look for the ABS braking strategies and track driving seminar video I posted up a while back. Its a very interesting watch. It's pitched low to make it accessible in terms of the info so suitable for all. Its interesting and the few minutes about ice mode may save your car or yourself.
If you found the time to send some emails off to people asking questions today, then you need to find the hour or so to watch that video.
The rest of the time no one really notices as it gets about its work quietly.
If you are interested, look for the ABS braking strategies and track driving seminar video I posted up a while back. Its a very interesting watch. It's pitched low to make it accessible in terms of the info so suitable for all. Its interesting and the few minutes about ice mode may save your car or yourself.
If you found the time to send some emails off to people asking questions today, then you need to find the hour or so to watch that video.
Edited by fioran0 on Monday 23 June 22:11
fioran0 said:
ABS is almost always doing something, particularly with pressures. It's only when you get into a proper mess and its intervention strategies kick in that you start to get things like the pedal pulses that everyone thinks of when they think of ABS.
The rest of the time no one really notices as it gets about its work quietly.
If you are interested, look for the ABS braking strategies and track driving seminar video I posted up a while back. Its a very interesting watch. It's pitched low to make it accessible in terms of the info so suitable for all. Its interesting and the few minutes about ice mode may save your car or yourself.
If you found the time to send some emails off to people asking questions today, then you need to find the hour or so to watch that video.
Excellent informative video.The rest of the time no one really notices as it gets about its work quietly.
If you are interested, look for the ABS braking strategies and track driving seminar video I posted up a while back. Its a very interesting watch. It's pitched low to make it accessible in terms of the info so suitable for all. Its interesting and the few minutes about ice mode may save your car or yourself.
If you found the time to send some emails off to people asking questions today, then you need to find the hour or so to watch that video.
Edited by fioran0 on Monday 23 June 22:11
I am still of the opinion that on a secondhand car PCCB's are worth having for a number of reasons. In some respects Porsche should be applauded for at least offering them as an option as I'm not sure any other manufacturer offers them as an option, regardless of anyones personal opinion as to whether they are worth the initial outlay.
I will still look out for a PCCB equipped car if I decide to buy a 981 Cayman when it is four years old or if I decide to have the full fat Parr turbo upgrade on my existing car I won't have to spend extra money upgrading my brakes so they may have saved me money in the long term.
I will still look out for a PCCB equipped car if I decide to buy a 981 Cayman when it is four years old or if I decide to have the full fat Parr turbo upgrade on my existing car I won't have to spend extra money upgrading my brakes so they may have saved me money in the long term.
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