PCCB vs Steel - Performance difference?
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daveo4porsche (08-31-2021)
08-30-2021, 09:57 PM
#62
Rennlist Member
it would be interesting to know of the Steel Cayman was “with in spec” for Porsche’s 25 stops from 80% of top speed (which is way more than 80 mph) - Porsche expect you to be able to apply full brakes from 80% of top speed and not go below 0.8/0.9 g’s deceleration - anything worse than .8 g’s would be consider a fail in Porsche’s testing/design metrics and Porsche brakes are supposed to offer that level of performance for 25 back to back runs…2.5 x times the 10 trials done in the video.
It would be really really easy to see if the Steel Cayman T was in “with in spec” for Porsche’s own design metrics/goals if we had the deceleration data from each of the trials - if the later trials - 7-10 for example where stopping distance was increasing by quite a bit due to brake fade and the deceleration g’s are less than 0.8 g’s - then we would know for some reason the Porsche Steel brakes are no longer with in spec for Porsche’s own standards…based on what I’m seeing int he video -I’d bet we’re way off of 0.8 g’s which is why the stopping distances are so bad - as to why that’s the case - well we’ll never know because the comparision was sloppy and poorly done - if the pads were 50% or less or the brake fluid was 2 years old that would be one possible problem of many.
It would be really really easy to see if the Steel Cayman T was in “with in spec” for Porsche’s own design metrics/goals if we had the deceleration data from each of the trials - if the later trials - 7-10 for example where stopping distance was increasing by quite a bit due to brake fade and the deceleration g’s are less than 0.8 g’s - then we would know for some reason the Porsche Steel brakes are no longer with in spec for Porsche’s own standards…based on what I’m seeing int he video -I’d bet we’re way off of 0.8 g’s which is why the stopping distances are so bad - as to why that’s the case - well we’ll never know because the comparision was sloppy and poorly done - if the pads were 50% or less or the brake fluid was 2 years old that would be one possible problem of many.
08-30-2021, 10:07 PM
#63
Rennlist Member
if you want to see some PCCB’s in action here is a video:
https://vimeo.com/394770248
time stamp 1:03 to about 1:35 is turn 11 to the long back straight down to turn 12 at Cota - I touch 154 mph and I’m into hard braking at 1.1 and 1.2 g’s in this section of track for every lap for up to 45 min sessions. I’ve driven COTA for at least 4 times for 3 days at a whack - so I have at least 12 days under belt at COTA and 100’s of laps in 911 cup car’s and various GT3’s with Porsche Steel and Porsche PCCB’s - both steel and pccb brakes can last ALL session with virtually no brake fade - and the differences in brake distance and power are mostly due to other factors - driver error is the dominate reason for any variance in my circumstance
when braking distance and performance starts to degrade - it’s not due to the type of brakes - it’s due to other factors - normally wear or fatigue
COTA is a hard and fast track - if you can run steel brakes all day long in the Texas heat at speed of more than 150 mph into heavy braking zones and not get any brake fade in 30-40 minute session - well then I’m not sure what type of street driving you’re doing in which Porsche’s steel brakes are not up to the task.
COTA is 20 turns - so that means 20 separate braking zone’s - many coming down from speeds in excess of 100 mph - a good lap time is 2:40’s or less - so 20 turns in 160 seconds or less means you are on the brakes “hard” about every 6 to 8 seconds - and you’re out for at least 12 laps in a 30 minutes session - and in at least 2 places you have extended hard braking - into turn 11 and into turn 12 - 12 laps at 20 turns on/off the brakes every 8 seconds slowing down a 3250 lbs GT3 from in excess of 150 mph and no brake fade on Porsche Steel brakes in 30 minutes…240 heavy brake applications in 30 minutes with no brake fade for Porsche steel brakes or pccb’s and consistent performance the entire time…tell me again about how you need PCCB’s for your street driving and you really feel Porsche’s steel brakes aren’t up to the task - I’m all ears.
https://vimeo.com/394770248
time stamp 1:03 to about 1:35 is turn 11 to the long back straight down to turn 12 at Cota - I touch 154 mph and I’m into hard braking at 1.1 and 1.2 g’s in this section of track for every lap for up to 45 min sessions. I’ve driven COTA for at least 4 times for 3 days at a whack - so I have at least 12 days under belt at COTA and 100’s of laps in 911 cup car’s and various GT3’s with Porsche Steel and Porsche PCCB’s - both steel and pccb brakes can last ALL session with virtually no brake fade - and the differences in brake distance and power are mostly due to other factors - driver error is the dominate reason for any variance in my circumstance
when braking distance and performance starts to degrade - it’s not due to the type of brakes - it’s due to other factors - normally wear or fatigue
COTA is a hard and fast track - if you can run steel brakes all day long in the Texas heat at speed of more than 150 mph into heavy braking zones and not get any brake fade in 30-40 minute session - well then I’m not sure what type of street driving you’re doing in which Porsche’s steel brakes are not up to the task.
COTA is 20 turns - so that means 20 separate braking zone’s - many coming down from speeds in excess of 100 mph - a good lap time is 2:40’s or less - so 20 turns in 160 seconds or less means you are on the brakes “hard” about every 6 to 8 seconds - and you’re out for at least 12 laps in a 30 minutes session - and in at least 2 places you have extended hard braking - into turn 11 and into turn 12 - 12 laps at 20 turns on/off the brakes every 8 seconds slowing down a 3250 lbs GT3 from in excess of 150 mph and no brake fade on Porsche Steel brakes in 30 minutes…240 heavy brake applications in 30 minutes with no brake fade for Porsche steel brakes or pccb’s and consistent performance the entire time…tell me again about how you need PCCB’s for your street driving and you really feel Porsche’s steel brakes aren’t up to the task - I’m all ears.
Last edited by daveo4porsche; 08-30-2021 at 11:59 PM.
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Schnave (08-30-2021)
08-30-2021, 10:38 PM
#64
Rennlist Member
well as reducing the braking distance from 100 km/h to 0 km/h of about 3 meters
ok 9 ft. from 100 km/hour - that’s 91.134442 ft/second
so 1/10th of a second improvement
https://www.martinreillymotors.com/news/?p=928
77.7 meters stopping distance in the dry - according to the website - so ideally PCCB’s will improve stopping distance by up to 3 meters / 77.7 meters = 3.89% improvement - I”m not sure I’d take that to the bank - but ok you win they are 3.89% percent better and cost more than a Honda Accord to replace.
You’re right they are better and Porsche is selling you a system that is 3.89% better for $9,080 option. Pretty on brand for Porsche I’d say right up there with the 17 kg carbon fibre weight savings on the GT3’s for $17,500 option…
I’ll consider the stopping distance improvement inconsequential but yeah you found someone willing to stick their neck out to document a 3.89% improvement in stopping distance - so I’ll take a daveo is partiallly wrong internet flogging. I can get you more than 3.89% by upgrading your tires however.
Last edited by daveo4porsche; 08-30-2021 at 10:44 PM.
08-30-2021, 11:14 PM
#65
Burning Brakes
what car - what tires - what break pressure and what pads, what tire pressure
ok 9 ft. from 100 km/hour - that’s 91.134442 ft/second
so 1/10th of a second improvement
https://www.martinreillymotors.com/news/?p=928
77.7 meters stopping distance in the dry - according to the website - so ideally PCCB’s will improve stopping distance by up to 3 meters / 77.7 meters = 3.89% improvement - I”m not sure I’d take that to the bank - but ok you win they are 3.89% percent better and cost more than a Honda Accord to replace.
You’re right they are better and Porsche is selling you a system that is 3.89% better for $9,080 option. Pretty on brand for Porsche I’d say right up there with the 17 kg carbon fibre weight savings on the GT3’s for $17,500 option…
I’ll consider the stopping distance improvement inconsequential but yeah you found someone willing to stick their neck out to document a 3.89% improvement in stopping distance - so I’ll take a daveo is partiallly wrong internet flogging. I can get you more than 3.89% by upgrading your tires however.
ok 9 ft. from 100 km/hour - that’s 91.134442 ft/second
so 1/10th of a second improvement
https://www.martinreillymotors.com/news/?p=928
77.7 meters stopping distance in the dry - according to the website - so ideally PCCB’s will improve stopping distance by up to 3 meters / 77.7 meters = 3.89% improvement - I”m not sure I’d take that to the bank - but ok you win they are 3.89% percent better and cost more than a Honda Accord to replace.
You’re right they are better and Porsche is selling you a system that is 3.89% better for $9,080 option. Pretty on brand for Porsche I’d say right up there with the 17 kg carbon fibre weight savings on the GT3’s for $17,500 option…
I’ll consider the stopping distance improvement inconsequential but yeah you found someone willing to stick their neck out to document a 3.89% improvement in stopping distance - so I’ll take a daveo is partiallly wrong internet flogging. I can get you more than 3.89% by upgrading your tires however.
2. Second, the stopping distance of a 911 carrera s is about 28m with steel brakes. So 3m better is a 10.7% shorter braking distance. Pretty significant.
Now you want to combine reaction time plus the braking, oh dear. Off another tangent again?
You can do all the google searches you want, i'll trust the manufacturer thank you very much.
08-30-2021, 11:16 PM
#66
Rennlist Member
1. First of all 3m is 9.8ft so please be accurate, nothing worse than not using correct numbers and just guessing like that.
2. Second, the stopping distance of a 911 carrera s is about 28m with steel brakes. So 3m better is a 10.7% shorter braking distance. Pretty significant.
Now you want to combine reaction time plus the braking, oh dear. Off another tangent again?
You can do all the google searches you want, i'll trust the manufacturer thank you very much.
2. Second, the stopping distance of a 911 carrera s is about 28m with steel brakes. So 3m better is a 10.7% shorter braking distance. Pretty significant.
Now you want to combine reaction time plus the braking, oh dear. Off another tangent again?
You can do all the google searches you want, i'll trust the manufacturer thank you very much.
08-30-2021, 11:31 PM
#67
Rennlist Member
1. First of all 3m is 9.8ft so please be accurate, nothing worse than not using correct numbers and just guessing like that.
2. Second, the stopping distance of a 911 carrera s is about 28m with steel brakes. So 3m better is a 10.7% shorter braking distance. Pretty significant.
Now you want to combine reaction time plus the braking, oh dear. Off another tangent again?
You can do all the google searches you want, i'll trust the manufacturer thank you very much.
2. Second, the stopping distance of a 911 carrera s is about 28m with steel brakes. So 3m better is a 10.7% shorter braking distance. Pretty significant.
Now you want to combine reaction time plus the braking, oh dear. Off another tangent again?
You can do all the google searches you want, i'll trust the manufacturer thank you very much.
https://www.motortrend.com/features/...nces-recorded/
the 2013 911 Carrera S stops in from 100 kmph in 93 ft with the steel brakes as documented by Motortrend (see above)
_IF_ ceramic brakes reduces that stopping distance by 9.8 ft (3 meters) that would make the 911 stop in 83.2 ft - which would be world leading and place a PCCB 911 at the top of it's class for ANY braking system on the market - and you think Porsche wouldn't NOTE that in their specs? I don't know a marketing person in the world that could resist that, and I don't know a VP in charge of sales that wouldn't fire any marketing person unwilling to promote that distinct advantage.
It's interesting to note that the same model in 2012 had a stopping distance of 98 feet, a 5-foot difference. In the performance car game, that's huge.
if anyone could have any evidence PCCB's offer statistically significant stopping distance improvements it would be kinda a big deal - but this isn't the first time this has been hashed, and we're not the only forum discussing it. In 10 years this is still being debated - why do you think that is?
so you believe a 2013 911 can stop in 83.2 ft from 100 kph by simply swapping to PCCB's and we've had 8 years to hear about this and yet there is no data being shared and no car mag has documented this 10% improvement?
that sort of difference would move the 911 from the #2 spot to the #1 spot for shortest braking distance of any car ever tested…I think we'd have heard about that.
what brakes are Brembo comparing themselves to? I doubt they are Porsche steel brakes.
but by your statement you believe Prosche PCCB"s will stop a 911 from 100 kph in 9.8 ft shorter stopping distance (83.2 ft vs. 93 ft) and this is a secret Porsche is unwilling to talk about because of potential liability?
Last edited by daveo4porsche; 08-30-2021 at 11:49 PM.
08-30-2021, 11:45 PM
#68
Rennlist Member
Porsche
BMW
Mercedes AMG
Ferarri
Lamborgini
McClaren
all of whom offer ceramic brakes - make no claims as to improved stopping distance or reduced stopping times - but all claim "better performance, lightness, and improved thermals for reducing brake fade".
no one documents improved stopped distance for their ceramic brake options.
BMW
Mercedes AMG
Ferarri
Lamborgini
McClaren
all of whom offer ceramic brakes - make no claims as to improved stopping distance or reduced stopping times - but all claim "better performance, lightness, and improved thermals for reducing brake fade".
no one documents improved stopped distance for their ceramic brake options.
08-31-2021, 12:14 AM
#69
Rennlist Member
https://www.bmwblog.com/2016/11/18/b...ic-brakes-bmw/
First seen in the limited-edition Mercedes CL55 AMG F1 in 2001, carbon ceramic brakes may not stop your car any faster than the standard brakes, but unlike the latter, they don’t overheat. Overheating causes the braking distance to increase and this is a huge problem for track goers, which makes ceramics ideal for them. That’s not to say that stock brakes on the M cars are any bad. When we drove the X6 M and M2 at the Circuit of The Americas and the Laguna Seca respectively, the cars didn’t have carbon ceramic brakes but we didn’t have any problem with brake fading. Yet, ceramics still fare better in preventing the brake fluid, pads and discs from blazing and that’s why BMW equips all its cars at the US Performance Centers with them (if they are available as an option). Moreover, a visit to the workshop for replacing the ceramic brakes will be more expensive than a trip to Bangkok. Now you might argue that ceramics last as long as the car, but that’s only under normal driving conditions. Frequent track drivers will tell you that while ceramics won’t wear out as quickly as the standard brakes, they are not un-breakable.
So should you buy them? Only if you don’t mind the cost. After all, they perform better, last longer and look freaking cool, especially with the bigger rims and BMW’s trademark golden calipers. Also, you can brag about how you use the same brakes as the racecars.
Last edited by daveo4porsche; 08-31-2021 at 12:16 AM.
08-31-2021, 12:19 AM
#70
Rennlist Member
I found something relevant from a Car and Driver performance brake test. Two identical 911’s with identical tires; one with PCCB and the other with iron brakes:
Not surprisingly, the Corvette and the two Porsche 911s performed very well in this test. We grew weary trying to the get their brakes to fade. All three cars survived more than 35 back-to-back stops from 100 mph without a decrease in performance. That feat is even more amazing when one considers the relatively brief 20-second interval between stops.
The 911 with the PCCB system performed about the same as the other 911 and the Vette. The average stopping distances of the two 911s were within a foot of each other (305 feet), not surprising since both cars were wearing the same tires. The Corvette averaged 326 feet. The conclusion: PCCB buyers enjoy a 37-pound weight savings but not necessarily more robust brakes.
Tires stop the car. Brakes stop the tires.
The 911 with the PCCB system performed about the same as the other 911 and the Vette. The average stopping distances of the two 911s were within a foot of each other (305 feet), not surprising since both cars were wearing the same tires. The Corvette averaged 326 feet. The conclusion: PCCB buyers enjoy a 37-pound weight savings but not necessarily more robust brakes.
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08-31-2021, 12:25 AM
#71
Rennlist Member
I found something relevant from a Car and Driver performance brake test. Two identical 911’s with identical tires; one with PCCB and the other with iron brakes:
Not surprisingly, the Corvette and the two Porsche 911s performed very well in this test. We grew weary trying to the get their brakes to fade. All three cars survived more than 35 back-to-back stops from 100 mph without a decrease in performance. That feat is even more amazing when one considers the relatively brief 20-second interval between stops.
The 911 with the PCCB system performed about the same as the other 911 and the Vette. The average stopping distances of the two 911s were within a foot of each other (305 feet), not surprising since both cars were wearing the same tires. The Corvette averaged 326 feet. The conclusion: PCCB buyers enjoy a 37-pound weight savings but not necessarily more robust brakes.
Tires stop the car. Brakes stop the tires.The 911 with the PCCB system performed about the same as the other 911 and the Vette. The average stopping distances of the two 911s were within a foot of each other (305 feet), not surprising since both cars were wearing the same tires. The Corvette averaged 326 feet. The conclusion: PCCB buyers enjoy a 37-pound weight savings but not necessarily more robust brakes.
this also calls in to question the awful performance of the Cayman T on steel brakes - there is NO reason in the world for that much brake fade in 10 trials from 80 mph - something was wrong with the Cayman's brakes - worn or simply not used correctly.
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Schnave (08-31-2021)
08-31-2021, 12:45 AM
#72
Rennlist Member
While researching, I found it amusing that this same debate is played out on Bimmerfest, Corvette Forum, Planet-9, Reddit, etc, etc, etc. . .
Speaking of which, how often should I change my oil? (Kidding) 😃
Speaking of which, how often should I change my oil? (Kidding) 😃
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daveo4porsche (08-31-2021)
08-31-2021, 12:47 AM
#73
Rennlist Member
I found something relevant from a Car and Driver performance brake test. Two identical 911’s with identical tires; one with PCCB and the other with iron brakes:
Not surprisingly, the Corvette and the two Porsche 911s performed very well in this test. We grew weary trying to the get their brakes to fade. All three cars survived more than 35 back-to-back stops from 100 mph without a decrease in performance. That feat is even more amazing when one considers the relatively brief 20-second interval between stops.
The 911 with the PCCB system performed about the same as the other 911 and the Vette. The average stopping distances of the two 911s were within a foot of each other (305 feet), not surprising since both cars were wearing the same tires. The Corvette averaged 326 feet. The conclusion: PCCB buyers enjoy a 37-pound weight savings but not necessarily more robust brakes.
Tires stop the car. Brakes stop the tires.The 911 with the PCCB system performed about the same as the other 911 and the Vette. The average stopping distances of the two 911s were within a foot of each other (305 feet), not surprising since both cars were wearing the same tires. The Corvette averaged 326 feet. The conclusion: PCCB buyers enjoy a 37-pound weight savings but not necessarily more robust brakes.
this test however is consistent with my assertion - tell me under what circumstance in normal street driving that you're going to fatigue Porsche Steel Brakes? And if you do…how are you not in jail?
PCCB"s make virtually no difference for anything other than track driving and even then it takes a lot to overwhelm Porsche's excellent steel brakes and get into any territory where PCCB's have a measurable advantage in terms of stopping distance and the only advantage PCCB's have is when compared to thermally saturaated steel brakes that can no longer generate enough friction to maximize tire grip.
You will never saturate your Cayenne's steel breaks in any legal driving circumstances or even slightly "extra-legal" highcrusing at 10-20 mph over the posted limit - because your brakes will be cool and ready when you need to use them and you won't need to use them 35 times in row from more than 100 mph with less than 20 seconds between applications…
Last edited by daveo4porsche; 08-31-2021 at 01:04 AM.
08-31-2021, 12:52 AM
#74
Rennlist Member
^^^That seems to be the consensus on multiple forums. Carbon Ceramics have a brake fade advantage only during extreme track use. No perceptible advantage on the street.
But they sure do look cool! 😎 Have I mentioned that before?
But they sure do look cool! 😎 Have I mentioned that before?
Last edited by Schnave; 08-31-2021 at 01:01 AM.
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daveo4porsche (08-31-2021)
09-02-2021, 01:03 AM
#75
Rennlist Member
Just a little cursory search of the interwebz and Brembo/SGL states this if you're interested. They manufacture all the carbon-ceramic brakes for Porsche and many others.
"The carbon-ceramic discs offer a 5-6 kg weight saving when compared to a traditional cast iron disc. They can last, depending on the driving style, as long as the life of the vehicle on which they are fitted, as well as reducing the braking distance from 100 km/h to 0 km/h of about 3 meters. Furthermore, Brembo's carbon-ceramic discs, resit to corrosion, they do not warp with temperature, they do not vibrate, they are reliable even when it rains and they provide the same braking force even after repeated operation and at low temperatures."
3meters or about 10 feet, not bad at all.
Some pretty compelling reasons right there from the manufacturer.
"The carbon-ceramic discs offer a 5-6 kg weight saving when compared to a traditional cast iron disc. They can last, depending on the driving style, as long as the life of the vehicle on which they are fitted, as well as reducing the braking distance from 100 km/h to 0 km/h of about 3 meters. Furthermore, Brembo's carbon-ceramic discs, resit to corrosion, they do not warp with temperature, they do not vibrate, they are reliable even when it rains and they provide the same braking force even after repeated operation and at low temperatures."
3meters or about 10 feet, not bad at all.
Some pretty compelling reasons right there from the manufacturer.