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The inherent weakness of PCCBs for Gen III+ is the lack of very frequent pad and fluid changes. It been my experience that if you change the pads when they reach 60% and fluid changes every other track event (no more than 6 track days, also with upgraded fluid) that the rotors will last years. I went three seasons of track days, about 90 days at some very brake intensive tracks and the rotors still passed minimum thickness levels.
From: Mid-Atlantic (on land, not in the middle of the ocean)
Originally Posted by cosmos
The inherent weakness of PCCBs for Gen III+ is the lack of very frequent pad and fluid changes. It been my experience that if you change the pads when they reach 60% and fluid changes every other track event (no more than 6 track days, also with upgraded fluid) that the rotors will last years. I went three seasons of track days, about 90 days at some very brake intensive tracks and the rotors still passed minimum thickness levels.
The PCCB rotors run out of life as they lose carbon content from oxidation, not loss of thickness.
Would like to think ducting and cooling improves generation to generation which would help extend the life of PCCBs since heat is what ultimately increases oxidation. I just checked pads last night. I'm at 8/12mm and 9/12mm, around 67% so I'll do one or two more track day on these pads and swap out like those above have said. If I'm able, I almost always try to do an extra cool down lap each session (if there are sessions) just to get heat out of the system.
From: Mid-Atlantic (on land, not in the middle of the ocean)
Originally Posted by Doublej
Would like to think ducting and cooling improves generation to generation which would help extend the life of PCCBs since heat is what ultimately increases oxidation. I just checked pads last night. I'm at 8/12mm and 9/12mm, around 67% so I'll do one or two more track day on these pads and swap out like those above have said. If I'm able, I almost always try to do an extra cool down lap each session (if there are sessions) just to get heat out of the system.
JJ
I've been tempted to get PCCB on the 992 GT3, but my wife will likely be the primer driver of the car on track, and she scoffed at the idea of doing an extra cool down lap, so maybe irons are best on this car.
You could spec the car with irons and then swap on Surface Transforms rotors.
I have PCCBs on my 981 GT4 and a set of Girodiscs for it. The weight difference is immediately felt through the wheel. Much prefer the characteristics of the car with ceramics. So I would order with irons and put the money into STs.
I've been tempted to get PCCB on the 992 GT3, but my wife will likely be the primer driver of the car on track, and she scoffed at the idea of doing an extra cool down lap, so maybe irons are best on this car.
Irons require longer cooldown, actually, because they have bigger mass and heat capacity with smaller surface area, so they take longer to shed the accumulated heat. In fact, one of the benefits of PCCBs is that they require noticeably shorter cooldowns. I melted many calliper seals after having to stop or pit in without full cooldown due to a red-flagged session - all with iron brakes, never with PCCB. PCCBs are more easily damaged due to offs or pads crumbling - it's very rare but when it happens it stings. Otherwise, they are better in multiple ways.
You could spec the car with irons and then swap on Surface Transforms rotors.
I have PCCBs on my 981 GT4 and a set of Girodiscs for it. The weight difference is immediately felt through the wheel. Much prefer the characteristics of the car with ceramics. So I would order with irons and put the money into STs.
i was told you could grind “re surface “ ST’s four to five times ? I like the red calipers over the black yellow .
I don't care what anyone says, but for me the PCCBs do feel significantly different than OEM irons. I had the same car (991 GT3), one with OEM irons and one with PCCBs, on the same track (Thermal) on the same day, and nearly the same time of day (9:30 and 10 a.m.) and just from my personal experience the GT3 with PCCBs handled and drove significantly better. Was the braking better? Not necessarily, but the handling, turn-in and more importantly the confidence it inspired in me that there would be no brake fade coming down a straight at 100+ ... the brakes would work as hoped and intended. That alone is worth the price of admission of PCCBs in my opinion. Was it placebo? Maybe, but again just the fact that it made me more confident was enough.
Doubt it was placebo. +/- 10 lbs. per corner. If an exhaust, battery, seat, anything saves 40 lbs., that's an objective performance advantage.
But if we apply that same weight savings into the most important component area on the car -- unsprung, rotating weight -- somehow it becomes debatable.
Don't run PCCB or ST for one reason and one reason only, too cheap.
Originally Posted by InfamousGT3
i was told you could grind “re surface “ ST’s four to five times ? I like the red calipers over the black yellow .
I've been told 3-4x. yes on ST compatibility with red calipers.
From: Mid-Atlantic (on land, not in the middle of the ocean)
Originally Posted by ipse dixit
This is my thought on PCCBs, or aftermarket ceramic rotors.
We are all driving/tracking essentially 200k cars. And, if you are, then your track budget should be commensurate.
Are PCCBs more expensive long term than OEM irons? Yes, for sure.
Are PCCBs significantly more expensive long term OEM irons? Not so sure.
The key to maintaining the durability and lifespan of the PCCBs (on the 991 and 992 cars) is to regularly swap pads, and to swap them right when they are less than 50%. Do this and you'll get at least 3, if not 4 or 5, pad swaps. Which in the long run, makes PCCBs near price parity with iron rotors.
Based on the above (swapping pads at around 45%) and swapping 3-4 times, I can easily get 30 full track days, if not more.
Now think about how much one is spending on tires for 30 full track days? One could be putting in new set of tires at approx 2500/set of Cup2s every time you swap out pads. 4 sets of pads, 4 sets of tires, that 's 10k in tires alone. And we're ok with that even though tires alone would be 1/2 of the cost of OEM replacement PCCB rotors.
Maybe you (not you specifically, but you generically) are still not convinced based on cost alone then there's the performance issue. I don't care what anyone says, but for me the PCCBs do feel significantly different than OEM irons. I had the same car (991 GT3), one with OEM irons and one with PCCBs, on the same track (Thermal) on the same day, and nearly the same time of day (9:30 and 10 a.m.) and just from my personal experience the GT3 with PCCBs handled and drove significantly better. Was the braking better? Not necessarily, but the handling, turn-in and more importantly the confidence it inspired in me that there would be no brake fade coming down a straight at 100+ ... the brakes would work as hoped and intended. That alone is worth the price of admission of PCCBs in my opinion. Was it placebo? Maybe, but again just the fact that it made me more confident was enough.
TL;DR. PCCBs when pads are changed at or just below 50% are no more expensive than OEM iron rotors and performance on track, real or imagined, are significantly better than OEM iron rotors.
So that's my 2 cents.
Others can disagree, which is fine, not here to argue.
Hope that answers your question.
As I’ve mentioned in some posts, I had the same experience when comparing a 991 GT3 with ceramics vs irons. It was a substantial difference in handling and brake feel in favor of ceramics. And it was sort of a blind test because I didn’t know until afterwards that the car which felt better had ceramics.
The OEM iron brake pads don't have strong bite and from my reading, I think the 992 OEM iron brake pads are even worse due to some of the materials restrictions that have gone into place recently. If comparing stock to stock, I am not surprised that some people comparing back to back like PCCB better.
If just talking strictly track, the OEM iron pedal bite can be improved substantially by using a pad like Ferrodo DS1.11 or DS3.12. In fact, my buddy (991.2 GT3 PCCB) and I (981 GT4 Iron w/ Ferodo) swapped and we didn't find a substantial difference in pedal bite. The Ferrodos take longer to come up to temperature and the first few cold braking applications didn't have much power. But the pads are used in actual race cars, so I don't think fade is really an issue with DS1.11 or 3.12, even at GT3 power levels.
In terms of the benefits of unsprung weight savings, well, that's a different story and defer to those that have done back to back.
I do not have too much to add to this other than we sell a lot of iron conversions for those who buy second hand GT3's with PCCBs.
PCCB brakes are not as efficient as their iron counterparts.
They must be larger and require more brake pad surface area to be as efficient.
The benefit is weight savings as mentioned earlier.
When you convert a PCCB car to iron rotors, the rotor is the same overall diameter but with a shorter annulus (pad depth). This is done to save weight on the iron rotor, and to keep the braking proportions the same.
On the 991/992 GT3 when you convert a PCCB car to iron you simply remove your ceramic rotors and pads and install a new Girodisc rotor with the iron shape pad, it's that simple.
Here is a iron 991/992 GT3 front brake pad, note the pad depth.
Here is a front PCCB 991/992 pad, also note the pad depth.
--Aaron
Hoping I can shed some light on this thread as I carry all options discussed here...
Originally Posted by Manifold
Have any of you tried a 992 GT3 on track with both PCCB and iron brakes? Is there a noticeable difference in handling of the car (due to less unsprung mass)?
Some customers swear that the car's handling improves significantly with ceramics, to the point that the lap times change by 1+seconds. Other customers don't notice a difference in that regard. I think alot of this comes down to the car, its setup, the driver, and the track being driven. I don't sell these for lap time improvements, whether they are present or not. It may also be a placebo effect in many cases. The majority of my customers that want ceramics, whether it be PCCBs or STs, do it for less brake dust, noise, and the ability to keep the same set of pads on the car whether they are on the street or track. The unsprung rotating mass argument is also strongest with ceramics. When compared to the factory 992 GT3 408/380mm iron discs, the ST rotors I sell save nearly 45 lbs of unsprung rotating mass. No other brake kit or disc even comes close to that (in terms of rotating mass), and I carry most of them. The 410/400mm ST discs weigh 14/14.5 lbs respectively per corner. Do what you will with that information.
Originally Posted by ipse dixit
Are PCCBs significantly more expensive long term OEM irons? Not so sure.
Was the braking better? Not necessarily, but the handling, turn-in and more importantly the confidence it inspired in me that there would be no brake fade coming down a straight at 100+ ... the brakes would work as hoped and intended. That alone is worth the price of admission of PCCBs in my opinion. Was it placebo? Maybe, but again just the fact that it made me more confident was enough.
Alot of good points here. I think the running costs of ceramics vs irons are narrowing. PCCBs are getting better and so are STs in terms of longevity as the manufacturing processes for both are constantly improving. As mentioned by others, the key is to keep more pad material on the when tracking the car, as this significantly improves the life of the ceramic discs. ST is also coming out with a new disc that reportedly will be a lifetime disc, even under heavy track use. These will cost more, but if the claims are valid it will be a no-brainer for those who track their cars a ton. For others, the current offerings will be more than sufficient, as are PCCBs in some cases. If you couldn't get PCCB and want ceramics, STs are a fantastic solution. $14K plus pads with Rennlist discount, much cheaper than $26K replacement PCCBs.
Originally Posted by cosmos
The inherent weakness of PCCBs for Gen III+ is the lack of very frequent pad and fluid changes. It been my experience that if you change the pads when they reach 60% and fluid changes every other track event (no more than 6 track days, also with upgraded fluid) that the rotors will last years. I went three seasons of track days, about 90 days at some very brake intensive tracks and the rotors still passed minimum thickness levels.
Case in point, if pad material thicknesses are kept in check, ceramics can last a very long time. That said, with your experience, you likely don't drag the brakes, which helps keep temps down significantly, further extending the life.
Originally Posted by Manifold
The PCCB rotors run out of life as they lose carbon content from oxidation, not loss of thickness.
Exactly, while their temperature threshold is very very high, that threshold can be exceeded (i.e. hard braking with no pad material left) and the disc wear/oxidation is accelerated, reducing disc life.
Originally Posted by Manifold
I've been tempted to get PCCB on the 992 GT3, but my wife will likely be the primer driver of the car on track, and she scoffed at the idea of doing an extra cool down lap, so maybe irons are best on this car.
I don't think the cool-down lap is as crucial. Ceramics are very stable and can handle heat, I would focus more on keeping 6mm or so of pad material on when tracking the car. Again, newer PCCBs are better. You may find however that upgrading to an aftermarket pad, ie. Pagid RSC1 will perform better and better handle the heat.
Originally Posted by InfamousGT3
i was told you could grind “re surface “ ST’s four to five times ? I like the red calipers over the black yellow .
We are throttling back on this claim as originally that was based on owners refurbing their rotors more frequently. The longer you go before/between refurbs, the more material has to be removed. That number is finite (1mm or so). If you go a very long time and have heavy oxidation, you may only get 1 or so refurbs. But at that point, you will likely have done 5K track miles or more. Every situation is different, so depending on how you drive/brake the car, the tracks driven, and the compounds being used, your disc life can vary significantly. In most cases, I would expect to get 2-3 refurbs if done more frequently. All of this said, I have been selling STs for a couple of years now and have yet to have a single one of my customers that I originally sold a set to reach out for a refurb...
The beauty of the ST kits is that they have offerings for those that either have factory PCCBs or Irons. I have a huge order of 992 GT3 incoming in a few weeks, for those that are interested. It is alot of money upfront, but I have not had a single customer regret purchasing a set. Noiseless, dustless, better feel and modulation. Thrash them on track and then drive to dinner without sounding like a garbage truck or fear that you trashed your $26K discs.
You could spec the car with irons and then swap on Surface Transforms rotors.
I have PCCBs on my 981 GT4 and a set of Girodiscs for it. The weight difference is immediately felt through the wheel. Much prefer the characteristics of the car with ceramics. So I would order with irons and put the money into STs.
I picked up a used set of ST rotors for my GT4RS at a very attractive price but I'll track the car with the OEM brakes to see how it feels for a handful of track day and then swap to the ST rotors with better pads and see if I can feel any difference.
06-20-2023 | 09:38 PM
