Sun Ra

Sloth,

i did plenty of track days with my SY GT2, now Todd's ride, and as long as you follow Bob Rouleau's advice [see his care and feeding a month or two back], you'll be fine. i was careful to blow the rotor holes clean with compressed air at the track.

Bob Rouleau

Watt - I feel obliged to point out that I did 40 odd track days with my GT2 and I did follow my own advice. Result - four dead very expensive rotors. It seems as I got more life out of mine that others but the result was the same.

Furthermore, my GT3 (ordered with cast iron rotors) brakes every bit as well as the highly vaunted PCCBs and are a lot less trouble. I know how to properly bed pads for iron rotors and I have a nice variety of pads to choose from. Consider that the so called race pads (Green) for PCCB have been reported as inferior to Pagid orange on iron rotors and in one case they failed. Who needs the headache?

Notwithstanding Watts wisdom, I think that anyone who tracks PCCB is asking for trouble. We're talking about $200,000 cars here (Watts remarkable ability to buy them for less notwithstanding) and spending 4 thou to avoid a costly problem seems trivial. Put it another way, has anyone who has driven PCCB and iron back to back come out and said that ceramics were better? There's nothing to lose by putting the damn things in a box and saving them for the next owner who will perhaps want them for the street. If Porsche had been more forthcoming about the problem I would have made the conversion a long time ago. As things stand I'm trying to prevent other owners suffering the same fate.

As always your mileage may vary but the odds are that it won't.

Best,

Sloth

Colm & Watt,

Thanks for the assurance, I will read up on Bobs advice on care and feeding. Part of me thinks they would be fine seeing as how I would not be pushing the car that hard... thats what I have the track cars for. The other part of me would just hate to toast them hoping that they would survive the weekend.

I have heard that at Sebring the ceramic rotors start to degrade when lap times get close to 2:20.x... and that is simply flying in my book. That has to be on R compound tires. My buddy figures he was turning 2.35's in his GT3 during a recent DE and I know my times would be slower still (2:40's or so).

Bob Rouleau

Sloth - two days of DE should not massacre your rotors if you are not hammering the brakes. On the other hand, saying I am only going to do 2 days of DE is like saying I will only have sex once <grin>.

I agree with Watt about PCCB on the street. In Canada there have been no issues with street driven cars with PCCB although you still have to keep the holes clean. This info came for the Tech rep - a guy you will get to know if you persist on tracking PCCBs.

A couple of data points which may help you (and others) is that the degradation of PCCB is not a linear progression. One you start to see discoloration of the rotors the rate of degradation accelerates. IN my case the right front rotor has a chunk missing! The left front has major discoloration around most of the other circumference. If you touch it, it feels like rough sandpaper. My rears appear to be ok on the outside. The inside edges (not normally visible to a casual inspection) are similar to the left front. All four are unusable. That's one of the reasons why I am changing all four to steel - the back ones lasted no longer than the fronts! Why? That's a good question as I normally replace steel rotors twice os often in front than in back. Something is very weird.

Two more item that you should add to the care and feeding of PCCB - do not use Green race pads. do not use pads that are 50 percent or more worn. The lack of heat dissipation of thinner pads will create even more hot spots which ruin the rotor.

Someone above summed it up well, for track PCCB sucks.

Carmelo Locurto

Sloth

I have called my dealer today & asked about them swapping pccbs for steels. Don't know where it will go, but just thinking maybe getting parts & labor N/C is better than saving pccb that no one will really want. Thoughts of $8200. lost sucks.

Bob

I think our region is attending a DE @ Tremblant with yours. Didn't see, where did your steel replacements from?

FixedWing

Sorry that you don't intend to discuss the issue further. Fortunately though, I am a real buffalo willing to talking to myself.

So far, I am the only one to complain of street damage here. I have heard stories in Europe of others though.

One reason might be that I have put 68,000 km on my system on a 996 Turbo. The Turbo is mostly intended for hard street driving. Most of these systems are mounted on GT2's and GT3's which are obviously track oriented cars and are going to cover far fewer street kilometres. A few C4S’s have also been sold with the PCCB system but I just don’t see the buyer of these cars using them as hard. Also, both the GT3 and the C4S with PCCB’s are very new cars which haven’t had time to cover any distance yet. There aren’t many GT2’s out there and many of these were originally delivered with cast iron. In Europe many of these customers got the word and refused to allow their cars to be converted to ceramics. Early days.

So what I’m saying is that I am one of the very few with any real experience of hard use on the street. Viewed in that light, I don’t think the numbers look so good.

To make use of more of your digits, the following was just posted to the U.K. GT3 mailing list:

Stephen

FixedWing

I think this is simply down to the type of use in Canada. No secret that street driving in Europe can be a lot tougher.

A lot of what you describe is what I saw too – especially the sandpaper feel and the differing rate of degradation on the inside vs. outside surfaces.

What do you mean by “chunk missing”? Do you mean a whole piece of the rotor was gone? In my case, the surfaces were all crazing and then flaking off. Most of the surfaces went quickly once it started to happen.

I didn’t see the discolouration of the rotors you describe. What I did see though was lots of transfer from the pads as they overheated. This looked like discolouration of the rotors. Are you sure this isn’t what you are seeing?

I’m hearing this a lot lately.

Stephen

Sloth

Now that I can agree with!

Bob Rouleau

Stephen - Yes, a chunk of the rotor was gone. The Service manual shows a drawing which is similar and it is one of the reasons to declare a PCCB rotor unserviceable.

There are (as you observe) two kinds of discoloration - one looks like deposits of pad material to me as well. The other is the result of the surface which has been worn off leaving the rough sandpaper-like gritty surface. Looking at the rotor with the triagular one inch by one inch chunk missing, it appears that the sandpaper- like surface is in fact the inner material of the casting itself since the color and the texture are the same.

Regards,

brh986

FWIW I cannot for the life of me understand watt's mindless defense of PCCB and Porsche on this issue. The rotors are supposed to last alot longer, period. There are MANY MANY documented cases of problems. For the longest time he kept saying that people must just be abusing them and not bedding them in properly pointing to Bob Rouleau as an example of proper use. Watt, why now that Bob's discs have failed do you continually stand behind such a shoddy over priced product? They were supposed to stop better/faster, they don't. They were supposed to last longer, they don't. Even Bob has said he got just as many track miles out of his iron discs in the past!

FixedWing

Bob,

Really unfortunate that you don't have photos but maybe you can compare what you saw on your own rotors to these photos taken of mine:





Full sized versions of the above (which really give you a feel for the depth) can be seen here:

http://www.986host.com/gallery/Fixed...ide_803?full=1

http://www.986host.com/gallery/Fixed...ide_795?full=1

What got me about my own rotors was that they had clearly got to the point of being dangerous yet everyone continued to insist that they were "okay". Ditto with the pads which would disintegrate. And now that you are telling me that chucks of your rotor were missing, I'm thinking the same thing -- these things are dangerous! Someone is going to get hurt. Porsche needs to care more about the physical well being of its customers. Dead customers don't buy Porsche.

Stephen

macfly

Wow, that is really ugly looking; once again I'm breathing that deep sigh of relief!

Larry Herman

Eeuuuwww, that's ugly. It looks like the surface is spalling (like old weathered concrete). I would guess that the heat is causing the surface to separate from the interior of the rotor and pop off in flakes. Definately a sign of overheating.

FixedWing

For what little it is worth, my conclusion was that the surface was heating and cooling at a different rate to the inside of the rotor due to the poor heat transfer of the material. I don't believe the rotors ever exceeded their supposed maximum temperature. This was the result of many cycles of heating and cooling -- something you are going to see more of on the street than at the track. I was often driving long distances where I would cruise at 250 km/h and then brake hard down to 200 km/h every time I came upon slower traffic. If traffic was blocking the fast lane then I often had to brake down to 120 km/h. I was doing this over and over again. I think this is the sort of heat cycling which destroyed these rotors. Which is why I think hard street use is a problem and maybe even more of a problem than track use.

I'm curious to know, whatever happened to the original PCCB photo on Porsche's web site? The one where they show them heating a rotor until it is glowing red on a test stand. For some reason, Porsche seems to have removed this one from their GT2 page and substituted some innocuous photos of a static calliper and rotor. Wonder why?

Stephen

0396

[QUOTE]Originally posted by watt
[B]Sloth,

"i did plenty of track days with my SY GT2, now Todd's ride"


Watt,

I happen to come across Todd's GT2 ride last month -
you should have seen the front rotors.....they look like
S_ _ T. Fronts look worse than Fixwings.

I guess he must have been doing some HEAVY street driving!