MJones

Since this is the 3rd time..
It would be interesting to hear the sequence of events surrounding incident 1 & 2
i.e. One track day or two...the firs dayt OK the second day bad.

Photos of the pads etc. would be nice...

You don't ever come off the track and keep the brakes applied at a stop to keep the car from rolling (just a cover the bases question)

BTW just because you read it in MT does not mean it is so.
Journalists are not the most reliable source of info.
I have yet to hear of CBC (Cornering Brake Control) in any of Porsches description of PSM regardless of the model.

The only descriptions are:
Traction Control (TC) for longitudinal dynamics,
with ABD (automatic brake
differential), ASR (anti-slip regulation) and
MSR (engine drag torque control)
systems and ABS (Anti-lock Braking
System). Stability Control (SC) for lateral
dynamics, particularly through wheel-
selective braking when over- or understeering.

iLLM3

This is extremely odd indeed wow... On my 996 GT2 my fronts wear out faster, but what Craig said complies with my experience of wear, rears are never as hot or worn.. I hope you come to some sort of conclusion, I can't imagine your frustration :/ Good luck

TrackDays247.com

The thing that would concern me is the INCREDIBLE heat - for brakes that large it takes a ginormous (that's big) amount of heat to change the caliper paint color - on a PCCB car!
It is just incredible.

Is there a chance the dealer is replacing the calipers and/or performing a complete system check?

fc-racer

Your brake system must be somehow engaged at all times. I'm assuming someone has checked to ensure that the master cylinder is good and there is no drag on the rear rotors (tough to do with the LSD back there).

PogueMoHone

^
Interesting observation, Castrol SRF has been known to corrode the seals in the master cylinder.

viperbob

As was mentioned, Porsche changed the bias DRAMATICALLY on the 997/987 cars to rear from front. You can read posts back to the first 997 GT3 track experiences on here (with Adam and his white 997 GT3)and the rears run much hotter than the fronts. Mdrums here had the same on his 997 (with multiple sets of rear calipers), and I have several other customers with various shades of Purple to brown on their rear calipers. So I am not overly surprised. I do find that the Pagid RS29 works as the best insulator for the heat though.

TrackDays247.com

Heard the same with SRF, FWTW.

Not saying this applies to your car, BUT:

I've had 3 customers install rear pads where the pistons were not pushed in enough, just that basic....result was ruined pads and purple/brown caliper(s)

Always were the rears.

Bill_C4S

Appears you are heat treating with phase change the calipers/pads and potentially rotors. Witness the paint colour change, and friability of the pads.

I'd guess temps approaching 1000F...which for a street pad would suggest constant friction between pad and rotor.

My concern would be catastrophic failure at the worst possible moment....

Getting a GT2 brake system expert - Porsche Motorsports NA? - to diagnose the system would be my first port of call.

Bob Rouleau

Bob, My 997 RS has over 50 track days. Front rotors replaced early this season. Rears are still original. Traction Control and a heavy right foot are the usual reason for premature rear pad/rotor problems.

In our local region the are a dozen 997Gt3s (most white!) and since turning off TC no issues. Same with a 997GT2, owner wore our rear PCCB in less than 3,000 miles. TC and his brutal driving style were the culprit. He was shown how to accelerate progressively and his rotor wear has gone back to normal.

The brake bias on the 997 is far superior to the 996 which had the fronts doing ALL the work. We used to use RS 19 in front and RS 14 in back to help balance the braking. It worked on the 996 GT3.

Neros must have a problem - sticking master cylinder maybe? FWIW, and youoprobably know better than I, a couple of locals have swapped their expensive PCCB rotors for iron ones from the Cup Car - a direct bolt on and far cheaper to replace than PCCB.

Best,

viperbob

Are up kidding? There is no such person and PM would not even talk to you about a GT2 (or a GT3 for that matter). OK to clear this up, the rears are biased to work hard. Maybe too hard for a street car. You can 1) stop driving DE 2) stop driving so fast or 3) try RS29 Pagid 4) try iron rotors to pull some of the heat out of the caliper. There is NOTHING wrong with your system that can be fixed unless you want to install a 996 type brake system. You will find no codes, and you can keep replacing components all the way through the brake system and you will have the same situation. The brake system is designed to do what it is doing. The only thing that MAYBE to check is that the TC is shutting down.

neros

I did. I had one track day on them and it ate through 50%. That day it ate through the remaining 50% and the calipers! I would have never expected the pads to last 2 track days only. I would love to just replace them with the GTR brakes from Brembo but there is a risk that this is a traction control issue where the rears will still be pulsed all the time and the new brakes might also overheat and then I have 2 brakes that don't work. I also don't want to completely disable traction control because I appreciate the help of ABS during braking.

LastMezger

RELEASE THE PARKING BRAKE! ;-)

neros

Dont have the pads pictures but there was basically nothing left since they crumbled and the pads we white since the overheated...

Porsche Motorsports recommended a green pad for the brakes...

neros

Just to correct something, this is the Second time this has happened but the car will have the Third set of brakes in 2,500 miles...

I have yet to see any mention of CBC anywhere (in fact all manuals say the GT2 is one of the only cars where you have complete control after traction control is off) but the Porsche Shop Foreman confirmed that even though traction control is off, he was told by Porsche that it does still kick in if it feels the tires spinning

neros

From Porsche Marketing Materials:
PSM
Some things never change, including driver expectations of a 911 GT2: sportsoriented
performance, a direct response and impressive power.
The 911 GT2 has a specially adapted version of Porsche Stability Management
(PSM). In addition to ABS, the package includes two automatic driver aids:
stability control (SC) and traction control (TC).
Stability control (SC), which is responsible for lateral dynamics, uses a range of
sensors to monitor the direction, speed, yaw velocity (speed of rotation around
the vertical axis) and lateral acceleration of the car. Using this information, it is
possible to calculate the actual direction of travel at any given moment. If the car
begins to oversteer or understeer, selective braking is applied on individual
wheels to restore control in critical driving scenarios.
Traction control (TC), with its integrated ABD (automatic brake differential), ASR
(anti-slip regulation) and EDC (engine drag-torque control) functions, is
responsible for the longitudinal dynamics of the car. Configured for sportsoriented
driving, traction control improves handling under acceleration on
surfaces with inconsistent grip. It also prevents the rear from ‘stepping out’ if a
wheel loses traction under full power. The trigger threshold is relatively high,
which means it is rarely employed in normal dry conditions.
Among the unique features of PSM in the 911 GT2 are the relatively high
intervention threshold on both control systems – enabling a more natural drive –
and the two-stage disable function for maximum driver control.
Stage 1 disables the stability control (SC) via the ‘SC OFF’ switch in the center
console. In ‘SC OFF’ mode, the control system does not intervene if the car goes
off-course in the lateral direction, which means the throttle can be used to help
steer the car. Traction control (TC) is still active in this mode.
Stage 2 disables the traction control as well via the separate ‘SC+TC OFF’
switch, giving the driver full command of the vehicle. Another unique feature is
the fact that stability control remains disabled in stages 1 and 2 even when
the ABS is required under braking. Specially developed for the 911 GT2, this
revised system strategy means the car can also be enjoyed to maximum effect
on the racetrack. (And Porsche tells me I should not drive this car on the track or it will void warranty!!! This is how they market the GT2!!!)
The anti-lock braking system (ABS 8.0) is integrated in PSM and remains active,
irrespective of which settings have been selected. ABS ensures a relatively short
braking distance and thus enhanced safety.
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