Palting

I apologize in advance because I've seen this before here on rennlist, but I can't seem to find it by searching the voluminous threads on PCCB.

There is a method or tool to determine the remaining carbon content on PCCB rotors to estimate remaining life. Can someone tell me what it is, please.

Thanks in advance!

Westcoast

I thought this was done by accurately weighing the rotor(?), if so you would have to know what it started at and compare that to the minimum weight printed on the hat.

Seth Thomas

No the new rotors are not weighed but measured for density using this tool.

https://porsche.snapon.com/special-t...temid=45090042

Westcoast

While that is an interesting process, they are indeed weighed and their minimum 'weight' is specified on the rotor... I believe that as the carbon in the rotor oxidizes the rotor will become lighter and this minimum weight is printed on it for reference.

Palting

Thanks, everyone! Got the answers I needed. Rennlist is the best!

ICE NAMAT

Hello, I am about to pull the trigger on a 911.2 GT3 RS with only 1,200 miles however I got these readings for the PCCB, my interpretation they are 50% -60%, what do you think? I was expecting readings over 50 at least, I don't mind buying a car that has been tracked but I may have to adjust my offer based on this finding. Thoughts?

Westcoast

Is this your test equipment? When was the last calibration? Are you 100% confident that using this method a Porsche PCCB rotor will be read correctly, as in a brand new one would actually show 100%?

If there is truly only 40+% remaining on the rotor then your offer would commensurate with this finding.

hsb1001

Need to be measured off the car, there is a specific process to measuring which Porsche does.

tgibrit

there is a very detailed thread on PCCB wear rates somewhere on this 991 GT3/RS forum, you might need to dig for it, it was a few years back but it was a thread many contributed to.

ICE NAMAT

no, this was done at a Porsche dealer, calibrated by the dealer, so it must been an adequate reading, I think

ICE NAMAT

Also, this gage measures how much carbon is left at each given point, you can see a reading at each measurement point and a reference value imprinted (aligned with the laser) that was performed during manufacturing, for example 52 /39 shows that the carbon content was at 52 when manufactured and that it should be replaced when it gets at or below 39, the gage reading shows 44.5 (measured at the spot marked with number) therefore 7.5 carbon units were depleted of an available of 13 (52 -39) therefore there are only 42.30% remaining units or rotor life.

My question is if you have seen this type of wear on a car with 1,200 miles... and if you can check my logic. thank you!

SmokinGTS

This does not look right. The rears should have no wear and same with the fronts for a car with 1200 miles. 2+2 does not equal 4. either the car has way more miles than advertised or was used for 24 hours on the Nurburgring ring trying to set a course record.

Wind911

It looks like the rotor is still on the car when the measurements were taken.
The rotor must be taken off the car, and someone mentioned also be vertical, when using the measurement tool. The reason being the metal parts in the vicinity will interfere with the tool and result in inaccurate readings.

Your readings are on the low side, even if all of the 1200 miles on the car are track miles will not wear out the PCCB rotors this fast.

ICE NAMAT

Thank you! This is very helpful. I am also thinking the rotors could be swapped with another car. All your comments are very helpful.

hsb1001

1200 miles would be the equivalent of 5-6 full track days or maybe a little more. Check that the car isn't a Porsche demo from the Atlanta center as those take a beating from day 1 and are usually sold via dealerships.

If you suspect the rotors have been swapped, check the piston's and the pucks / covers inside if they will show you, that way you will know 100% if these rotors have been used or its just a mistake somewhere.