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Pccb are great on a street car to avoid dust and especially on a lighter colored wheel. If i did a light wheel on street car, pccb is almost a must for me (cause I’m lazy). I agree the new gen pccb’s hold up MUCH better on track. The old 997 pccb’s could easily be smoked on track w/out trying very heard. I owned a 991.2 gt3 w/pccb’s; while I didn’t keep the car long, I tracked it a lot in a short amount of time. My shop told me to go ahead and track the oem ccb’s w/out much worry; and switch to surfaces if I was going to keep up that pace for years (I was not). I winced the first few times out. But when I sold it to the next buyer, the rotors were never an issue.
As such, I have a 997 with black wheels and irons. Luckily the CGT has CCB for the light silver wheels. Although, you wanna talk about silly oem replacement cost! That thing will get surface transforms if/when it ever touches a circuit. Chances are I won’t have the ***** to push it hard enough to matter, but I don’t want to risk a 50k brake job!
My fairly limited experience opinion is that if you plan to track it every-once-in-a-while and aren’t pushing to set circuit lap-times, you will be fine with this new gen of CCB. If you are gonna track it to an inch of its life, get irons. If it’s mainly street and especially light wheels, pccb. If you hate yellow or red calipers, well, idk what to tell you then?! Don’t get me started on Porsche changing their yellow to racing but leaving the CCB pad color speed! I never noticed any real performance differences on track between the two with exception that sometimes the ccb’s need a little more time to warm up especially on a really cold day. Then again, I’m not that good and can’t push a car nearly as hard as a lot of guys on this forum.
I don't understand the philosophy of buying PCCBs, then taking them off to retain life for resale value. I don't believe you get the full $8k back at sale time anyways. Why buy PCCBs if you don't get to enjoy them? I don't spec my cars for the next guy, so I guess I don't get it.
Because paying 20 k every 18 months to replace pads and rotors as opposed to 5 k is not particularly appealing. Having owned a few pccb cars I now spec steel as I track a lot. I also like the feel of steel better under heavy braking as you can modulate steel, actually iron, far better than pccb's.
Not everyone orders their cars and not everyone has learned the lessons of heavy tracking with pccb's . Even AP has said many times buy steel if you are a track rat.
PS plus one for Jeff and the folks at AP. Real pros and good people.
Uh, wait a minute... why I'm reading that Iron brakes perform better on track than PCCB?
Carbon Ceramics fade is almost non-existent with the increase of temperature, so they don't fade as nearly as Iron do. therefore PCCB are the most extreme and suitable for racing.
That being said, there's the new PSCB (Tungsten-Carbide-Coated) that seats in between an Iron and a PCCB. I presume that this one's will become the favorite choice because they have a similar fade tolerance than PCCB but at a third of the price and they don't generate as much dust as Irons.
So here's a Fade comparison Between Irons and PSCB, where if the PCCB were shown would be even more stable than the PSCB
So in summary the hierarchy would be in this order:
3)Irons
2)PSCB
1)PCCB
The same principle applies to:
3)GT4
2)GT3
1)GT2.
One may say that GT4 is the more enjoyable, but you just cannot say that a GT4 outperform a GT2? right?
Irons for track. Lower replacement costs, get some aftermarket pads to improve performance. Upgrade entire brake from there if you even need to. Most wont need to.
Having said that I have PCCB coming on my Spyder, looking forward to trying them out for all their STREET benefits.
Uh, wait a minute... why I'm reading that Iron brakes perform better on track than PCCB?
Stopping from 100mph to 0mph, 14 times in a row is not the same duty cycle the brakes will see on the track.
I 100% agree that PCCBs are higher performing brakes than irons. However the irons on the 718 GT4/Spyder are more than capable of handling track work without fade so the benefits of PCCB are negligible to improve braking performance. Its a solution to a problem the car doesn’t have. The benefit of PCCBs is primarily less unsprung rotating weight and a lighter car is going to be a faster car.
Below is a table from a back to back test of carbon ceramics vs iron brakes on the same car, on the same day.
The test was consecutive crash stops from 100-0 mph which is much, much tougher a test than anything you do on a track.
As you can see, for the first 12-13 crash stops, its pretty even with the iron brakes stopping shorter that the ceramics on multiple occasions. Th ceramics only outperformed the irons for the the last 8 stops.When the testers were asked if they was surprised that the cast iron brakes achieved shorter stopping distances at normal operating temperatures, they responded: ‘Not really. There’s [very little between the two setups] and on the presumption this is well into ABS then the adhesion utilisation of the tyre from stop to stop could cause that level of variation. Basically, neither of the brakes is fading at this point. The differences in the ten shortest stops are not because of the brakes. In the normal temperature window, once you’re in ABS then it’s not the brakes that are the limiting factor: it’s purely the tyre-to-road adhesion and the ABS tune.’ The test shows that ceramic brakes are ultimately more resilient, but only in extreme, almost unnatural, circumstances.
The last two remarks about the limiting factors of ABS and Tyres is consistently overlooked. i.e. the brake distance is more often determined by the calibration of the ABS, the adhesion ability of the specific tyre on the car under extreme braking load and, I might add, the quality of the surface under the car. Indeed, on almost any track, the limiting factor to everything is always going to be the tyres because after 6-10 laps you are going to have to stop anyway to give the tyres a rest.
And as I always said, I have never been oufbraked by a PCCB car on any track.
I tried convincing myself to the value of PCCBs but in enthusiastic street driving, other than a slightly different brake feel, there was no other difference or improvement i could detect. Perhaps on the track, in the hands of a highly capable driver pushing the car at 10/10s, the weight reduction and resistance to fade might be discernible. But the conventional wisdom seems to be to go with irons on the track.
So then we’re back at looking at street use. Pros and cons: Cool tech, no brake dust, “unlimited“ service life vs rotor fragility: susceptibility to chips. Since i didn’t want to worry every time I kick up some gravel nor do i want to be busy explaining how to change the tire without chipping the rotor, i went with irons.
Bottom line, both choices give the 718 GT4/Spyder world class stopping power.
I found this interesting though i can’t attest to it’s accuracy. If it is accurate, it should be noted that the PCCBs weight savings is 50% greater in real world terms so 40lbs unsprung is more like 60lbs in actual sprung weight reduction. PCCBs along with a light weight battery and LWBS could shave a good 130 lbs off the Spyder/GT4.
Originally Posted by Mech33
40 pounds of rotating mass that is removed uniformly along a disc that is the full radius of the tire is only equivalent to removing about 60 pounds of regular mass acceleration-wise (you only get a 50% bump associated with it being rotating, contrary to popular believe). In the case of PCCB, it would be even less since the rotors are a lesser diameter than the tire. . . . I'm just talking about linear acceleration...
Originally Posted by Jawnathin
Stopping from 100mph to 0mph, 14 times in a row is not the same duty cycle the brakes will see on the track.
I 100% agree that PCCBs are higher performing brakes than irons. However the irons on the 718 GT4/Spyder are more than capable of handling track work without fade so the benefits of PCCB are negligible to improve braking performance. Its a solution to a problem the car doesn’t have. The benefit of PCCBs is primarily less unsprung rotating weight and a lighter car is going to be a faster car.
I found this interesting though i can’t attest to it’s accuracy. If it is accurate, it should be noted that the PCCBs weight savings is 50% greater in real world terms so 40lbs unsprung is more like 60lbs in actual sprung weight reduction. PCCBs along with a light weight battery and LWBS could shave a good 130 lbs off the Spyder/GT4.
Where is everybody getting those weight figures from? Didn’t Pete already address this? PCCB calipers are larger than iron ones = weight gain instead of loss. PCCB rotors are larger than iron one but built differently = weight loss. But 10 lbs each corner I seriously doubt that.
Where is everybody getting those weight figures from? Didn’t Pete already address this? PCCB calipers are larger than iron ones = weight gain instead of loss. PCCB rotors are larger than iron one but built differently = weight loss. But 10 lbs each corner I seriously doubt that.
PCCB and Iron Calipers are identical except for the mounting ears being a bit longer on PCCB (15mm front and 5mm rear to place them a bit more outboard of the hub for the larger diameter rotors). Weight difference is very minimal.
Below is a table from a back to back test of carbon ceramics vs iron brakes on the same car, on the same day.
The test was consecutive crash stops from 100-0 mph which is much, much tougher a test than anything you do on a track.
As you can see, for the first 12-13 crash stops, its pretty even with the iron brakes stopping shorter that the ceramics on multiple occasions. Th ceramics only outperformed the irons for the the last 8 stops.When the testers were asked if they was surprised that the cast iron brakes achieved shorter stopping distances at normal operating temperatures, they responded: ‘Not really. There’s [very little between the two setups] and on the presumption this is well into ABS then the adhesion utilisation of the tyre from stop to stop could cause that level of variation. Basically, neither of the brakes is fading at this point. The differences in the ten shortest stops are not because of the brakes. In the normal temperature window, once you’re in ABS then it’s not the brakes that are the limiting factor: it’s purely the tyre-to-road adhesion and the ABS tune.’ The test shows that ceramic brakes are ultimately more resilient, but only in extreme, almost unnatural, circumstances.
The last two remarks about the limiting factors of ABS and Tyres is consistently overlooked. i.e. the brake distance is more often determined by the calibration of the ABS, the adhesion ability of the specific tyre on the car under extreme braking load and, I might add, the quality of the surface under the car. Indeed, on almost any track, the limiting factor to everything is always going to be the tyres because after 6-10 laps you are going to have to stop anyway to give the tyres a rest.
And as I always said, I have never been oufbraked by a PCCB car on any track.
This is very interesting data. It is also my understanding that PCCB has a higher lower temp for optimal performance. So when cold, the irons will perform better. Where PCCB benefits is resisting brake fade when the temp goes up due to extended usage (like on a track).
This is very interesting data. It is also my understanding that PCCB has a higher lower temp for optimal performance. So when cold, the irons will perform better. Where PCCB benefits is resisting brake fade when the temp goes up due to extended usage (like on a track).
That is correct. I also wonder how much of the fade resistance of PCCB's is due to the pads used. I imagine that upgrading the pads with the iron rotors will provide the same level of fade resistance. The iron brakes on the GT4/Spyder are identical to those on the heavier and much faster GT3RS - the irons are already overkill for 718.
Where is everybody getting those weight figures from? Didn’t Pete already address this? PCCB calipers are larger than iron ones = weight gain instead of loss. PCCB rotors are larger than iron one but built differently = weight loss. But 10 lbs each corner I seriously doubt that.
07-13-2020, 04:38 PM
