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My car is in the dealer for some work and they are going to measure my pccb as well.
To note, their GT specific tech ( only works on the GT3RS/GT3/GT2 ect) said the 991/981 are greatly improved in their wear vs the 997 and previous gen. He told me he's seen some 2014 Gt3 with tons of track use with no major concerns yet. Good to hear!
So, this update will surely generate some controversy.
I took my PCCB rotors off last winter and had them measured (see the beginning of this thread). Did the same thing this week and just got back from the dealer with my rotors.
Since February 2017, I've added about 1,500 track miles and about 3k miles total. Guess what? Essentially ZERO wear has been measured since then.
Now, I'm not silly enough to believe that there has been zero wear. However, I think it's safe to say that these rotors are wearing very well.
I'm a red group driver (open passing), typically pretty fast, also typically smooth and very progressive with my braking and don't use ABS much (former Spec Racer Ford driver, pure momentum car). I drive with all nannies ON. I also use brakes as little as possible on the cool down lap and also drive around the paddock for a few mins before parking.
I was planning to switch to Giros or maybe Racing Brake (Brembo carbons) or Surface Transforms, but at this rate, I think I'll just get new OE pads and keep running PCCBs.
My GT4 is stored on my 4-post lift currently with a cover on it so I don't have the exact mileage and I forgot to measure the pads. They're still the original pads. I'll try to get a measurement shortly.
Also, note that I rotated pads inside/out (but I kept them on the same corner) last year when I had my rotors measured.
Thanks for the data point.
Having read that you managed 3000 track miles on one set of OEM pads gets me thinking that you might not be using all the brakes you have.
Or am I misreading that you're still running the pads the car left the showroom with?
Thanks for the data point.
Having read that you managed 3000 track miles on one set of OEM pads gets me thinking that you might not be using all the brakes you have.
Or am I misreading that you're still running the pads the car left the showroom with?
Correct, still on the original pads as delivered. I'll measure them tonight -- they're probably down to 8mm - 10mm in pad material thickness.
1. Does changing from ceramic to steel rotors invalidate all or part of the factory or CPO warranty? I have a CPO 2016 GT4 and am contemplating switching to steel rotors until I become a competent track driver.
2. According to the 991 thread mentioned above, ceramic rotors may fail in ways which are visible. They may also be worn past their useful life as detected by the Porsche tool (which checks density, I believe). How can a PCCB-equipped car be tech inspected accurately prior to track events given that some rotors past their useful life can be detected only with the Porsche tool?
I'd appreciate others' interpretation of the attached PCCB wear as measured by the Porsche tool. Some specific questions:
1. Why would the left rear have an average wear of only 11% when all of the others are in the low-to-mid 20's? Track use with lots of left turns? I notice that johnsopa's data shows a similar effect: about 1/2 the wear on the left rear tire compared to the other 3.
2. Does anyone know the meaning of "Functional Test Deviation"? It is circled in the upper right corner of the results.
3. An observation: There is error associated with any measurement, even if if the measurement is performed correctly. I wonder what the accuracy is of the Porsche tool and if the inherent accuracy of the tester might explain any of the strange readings observed previously, such as the wear decreasing over time or the fact that one of my readings showed 0 wear despite 5656 miles. It would be an interesting test to make two consecutive readings (ie, without re-mounting the rotor) on a set of rotors to see how large the reading-to-reading variation is.
4. Question: When does Porsche mandate replacement of the rotor? Is replacement based on the average wear for the rotor, or just one of the 3 readings being beyond the wear limit?
5. Do both rotors on an axle need to be replaced if only one rotor is beyond the wear limit?
Bottom line: I wonder if we all are "chasing our tails" because the accuracy of the measurements using the Porsche tool is low.
BTW, my guy at the porsche dealer indicated that switching to steel/iron rotors from PCCB would not invalidate my CPO warranty.
I'd appreciate others' interpretation of the attached PCCB wear as measured by the Porsche tool. Some specific questions:
1. Why would the left rear have an average wear of only 11% when all of the others are in the low-to-mid 20's? Track use with lots of left turns? I notice that johnsopa's data shows a similar effect: about 1/2 the wear on the left rear tire compared to the other 3.
2. Does anyone know the meaning of "Functional Test Deviation"? It is circled in the upper right corner of the results.
3. An observation: There is error associated with any measurement, even if if the measurement is performed correctly. I wonder what the accuracy is of the Porsche tool and if the inherent accuracy of the tester might explain any of the strange readings observed previously, such as the wear decreasing over time or the fact that one of my readings showed 0 wear despite 5656 miles. It would be an interesting test to make two consecutive readings (ie, without re-mounting the rotor) on a set of rotors to see how large the reading-to-reading variation is.
4. Question: When does Porsche mandate replacement of the rotor? Is replacement based on the average wear for the rotor, or just one of the 3 readings being beyond the wear limit?
5. Do both rotors on an axle need to be replaced if only one rotor is beyond the wear limit?
Bottom line: I wonder if we all are "chasing our tails" because the accuracy of the measurements using the Porsche tool is low.
BTW, my guy at the porsche dealer indicated that switching to steel/iron rotors from PCCB would not invalidate my CPO warranty.
Were the rotors measured OFF the car? Measuring on the car can create odd results....
They charged me $300 in labor to perform the rotor measurements. Thus, I assume the measurements were made with the rotors off the car.
If Porsche techs are not consistently making the measurements using the same procedure, then we really are chasing our tales. Given the rotor replacement costs and human safety at stake , inconsistent procedures in making the measurements of the rotors should probably be addressed via the courts.
They charged me $300 in labor to perform the rotor measurements. Thus, I assume the measurements were made with the rotors off the car.
If Porsche techs are not consistently making the measurements using the same procedure, then we really are chasing our tales. Given the rotor replacement costs and human safety at stake , inconsistent procedures in making the measurements of the rotors should probably be addressed via the courts.
Assume if you like but if you want to know I would ask. I think it's fair to say Porsche dealer service prices have almost zero correlation with quality of service.
01-18-2018, 10:52 PM
