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Dee

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I return you to the 4 superpowers of the $9,080 Taycan PCCB option
  1. superior thermal endurance
  2. lack of brake dust
  3. lower unsprung rotational mass
  4. buy the look
5. Better ride quality due to the lower unsprung weight (>50% cast iron brakes).

I can't help notice that wherever there's the mentioning of ceramics you can't stop telling people why it's a waste of money.
In that logic, buying a Taycan is a waste of money too cuz you can buy a lot of other cars which are way cheaper but drive as good as, or even better than a Taycan.
If you like PCCB's go for it, it's just supercool to have.
You're kinda spoil the mood by saying they are "useless" and "a waste of money".
Why so serious?
Don't bring down everything by relativation, it's just nice to have such a piece of racing technology on your vehicle. 😉
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daveo4EV

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5. Better ride quality due to the lower unsprung weight (>50% cast iron brakes).

I can't help notice that wherever there's the mention of ceramics you can't stop telling people why it's a waste of money.
In that logic, buying a Taycan is a waste of money too cuz you can buy a lot of other cars which are way cheaper but drive as good as, or even better than a Taycan.
If you like PCCB's go for it, it's just supercool to have.
You're kinda spoil the mood by saying they are "useless" and "a waste of money".
Why so serious?
Don't bring down everything by relativation, it's just nice to have such a piece of racing technology on your vehicle. 😉
then add the $460 400V/150 kW charger and we'll both be good…

yes they are cool - but very very pricey for limited benefit.
 
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then add the $460 400V/150 kW charger and we'll both be good…

yes they are cool - but very very pricey for limited benefit.
I'll add what I like, no need to do that for me.

You think it's pricey but that's just an opinion.
Stop being annoying, we got it: you don't think it's worth it.
No need to tell that over and over again.
Look at your posts, so many words, just to explain it's not worth it.
My god...
 

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I'll add what I like, no need to do that for me.

You think it's pricey but that's just an opinion.
Stop being annoying, we got it: you don't think it's worth it.
No need to tell that over and over again.
Look at your posts, so many words, just to explain it's not worth it.
My god...
no I'm not a god -b ut thank you for thinking so.

you option what you wnat and I'll post what I want - there we both agree.
 

Mike in CA

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The 911 CupCars and GT4 Clubsports (non-street legal dedicated race cars) do NOT come with PCCB's.
Probably because IMSA brake regulations (Section 2.4.1) do not allow for carbon ceramic rotors on the 911 GT3 Cup.

TR-PCCNA-2022-Technical-Regulations-REDLINE-02232022.pdf (imsa.com)

yeah - 5,100 lbs car - the unsprung weight advantage of PCCB's probably isn't it's biggest problem.
I don't think anyone is suggesting that un-sprung weight is the Taycan's biggest problem, only that reducing it does have benefits as exemplified by @Skilly's experience with his R8 and the analysis in the video at the top of this thread.

Whether that benefit is "worth it" is wholly subjective, but I think we are all capable of making the value judgement. To each his/her own. ;)
 
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I would think from my experience the difference in both unsprung weight and rotational inertia by replacing the iron discs with composite would be negligible.

I tested a F1 car on the chassis dyno to see how big a gain fabricated titanium uprights would be over steel and the gain was invisible in terms of load fluctuation - ie it made no difference to grip or ride and the car mass to unsprung mass ratio is massively more unfavourable on a F1 car than a road car already.

The rotational inertia is totally dominated by the tyres. A bit of work on the wheel rim makes a tiny difference but the brake rotors are too small in diameter to have a substantial moment of inertia anyway.

Obviously any optional extra somebody wants to spend money on is a personal choice and I do think they look nicer but if somebody feels a noticable performance difference on the road it is 99.9% likely to be expectation bias, not a real difference.
confirmation/expectation bias is a powerful thing
I agree and expect it's negligible vs. all the other factors on this vehicle
 

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I would think from my experience the difference in both unsprung weight and rotational inertia by replacing the iron discs with composite would be negligible.

I tested a F1 car on the chassis dyno to see how big a gain fabricated titanium uprights would be over steel and the gain was invisible in terms of load fluctuation - ie it made no difference to grip or ride and the car mass to unsprung mass ratio is massively more unfavourable on a F1 car than a road car already.

The rotational inertia is totally dominated by the tyres. A bit of work on the wheel rim makes a tiny difference but the brake rotors are too small in diameter to have a substantial moment of inertia anyway.

Obviously any optional extra somebody wants to spend money on is a personal choice and I do think they look nicer but if somebody feels a noticable performance difference on the road it is 99.9% likely to be expectation bias, not a real difference.
No disrespect meant in my thoughts reading this but it's all based on theory while you watch numbers on a test bench.

F1 is THE pinnacle of auto racing were any micro adjustment is material to competitive team. I mean, consider that the paddock moved from fabric logos on a fire suit to ink for weight savings! If I were looking from the outside my 'expectation bias' says that's insanity...every team does it though.

The drivers pick up tactile differences in the car that are barely detectable from the sensors; to engineers it will look identical by the numbers. To them and the timers it might translate to the difference between P1 and P3. Driver input is one of the key variables in all of it. They run those cars on the limit around every inch of the track, test, quali or race. If you adjusted any parameter in the car, let alone rotational mass or unsprung weight they would detect it. In fact, the teams that take championships tend to build cars around drivers feedback/skill set almost as much as they consider the regulations.

When I did my upgrade on the R8, I wasn't expecting such a drastic change, but was pleased beyond when I did. I can't speak for another driver being able to detect what I did but it was there. Moreover, if I hadn't had the chance to compare pre/post with seat time, any of my feedback on one or the other on the change in the car's driving would have been theoretical. In fact, I probably would have been skeptical of it altogether.

I wouldn't have had anything other than my own bias and experiences with one or the other set up - kinda what seems to be happening here.
 


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I would think from my experience the difference in both unsprung weight and rotational inertia by replacing the iron discs with composite would be negligible.

I tested a F1 car on the chassis dyno to see how big a gain fabricated titanium uprights would be over steel and the gain was invisible in terms of load fluctuation - ie it made no difference to grip or ride and the car mass to unsprung mass ratio is massively more unfavourable on a F1 car than a road car already.

The rotational inertia is totally dominated by the tyres. A bit of work on the wheel rim makes a tiny difference but the brake rotors are too small in diameter to have a substantial moment of inertia anyway.

Obviously any optional extra somebody wants to spend money on is a personal choice and I do think they look nicer but if somebody feels a noticable performance difference on the road it is 99.9% likely to be expectation bias, not a real difference.
Your experience notwithstanding, to keep things in perspective, the 15-16" cast iron brake rotors used on modern Porsches, including the Taycan, are actually larger and heavier than the wheels of the F1 car you tested on the chassis dyno.

At around 35 pounds apiece the larger Porsche cast iron rotors, especially PSCB's, are also heavier than the 265 and 305 tires that are fitted to 21" wheels on the Taycan. For example, the Michelin PS4's that are now available weigh in at 26 and 29 pounds respectively. If, as you say, rotational forces are dominated by the weight of the tires, I would suggest that the weight of still heavier brake rotors will also have an effect.

I didn't drive a non-PCCB equipped Taycan for any length of time so I can't make a claim of improved ride quality or steering feel related to "confirmation bias", but it does make sense to me that removing up to 15 pounds of unsprung weight from each wheel would have an effect somewhere beyond "negligible". I also think that someone who has made a back-to-back comparison of cast iron to ceramic rotors on their own car and experienced a difference is not in their own head "99.9%", a number that appears to have been pulled out of thin air.

I bought PCCB's mainly because they don't make dust and they look fantastic. I believe that they also offer some less obvious additional benefits but If people feel a need to spend their time trying to disabuse me and others of that notion, then continue to have at it.
 

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I don’t have ceramics and have never experienced it myself, however I’ve seen many track rats retrofit their ceramic brake cars with iron rotors; just google “iron retrofit brakes Porsche” and you’ll see for yourself. Despite the lower fading, longer life etc people chose to pay extra for an iron kit and get it fitted. Of course professional race teams don’t do this, because ceramics are better. But everyday joes know that a small mistake will cost them the equivalent of 2-3 iron kits so they chose the safer route
Yeah, it's not that simple. Track rats usually run iron rotors for a number of reasons, the biggest of which is simply cost. And race teams don't run carbon ceramics, they run speciality carbon-carbon brakes.

And as others have said, this idea that carbon ceramics are brittle china dolls is just not true. Do they damage easier than iron? Sure, but not by a huge measure, Internet anecdotes notwithstanding.

I went PSCB instead of PCCB this time because I just didn't think I'd be using the actual rotors on this car very much, but I would be on the fence if I were to order a new car.

BTW, anyone who thinks you can't tell the difference in unsprung weight, go drive a GT4 or Spyder with PCCB and without back to back. It is absolutely noticeable how differently the car turns in.
 

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The unsprung mass changes I have tried makes very little difference to wheel load fluctuations (which is the grip determining parameter from the suspension dynamics) even on a light F1 car IME and FYI the rotational inertia is dominated by the tyre because its mass is concentrated in the belt and tread and since the value is determined by radius squared the tyre is the big thing not the brake rotor.

As far as I am concerned the brake choice on a Taycan is for styling not performance, unless you do track days.
So, you're saying that un-sprung mass has virtually no effect (or "makes very little difference" in your words) on handling, turn in, steering feel or performance? Almost makes one wonder why anyone would bother with lightweight wheels, brakes and suspension components.

If you search the internet for an answer to the question "Does reducing un-sprung weight make a difference" you will find that the overwhelming response is "yes". In fact, it's extremely difficult to find an article with a contrary opinion. Of course, that doesn't prove anything. But at the very least it suggests that there are reliable sources who take a position contrary to yours on the effects of un-sprung mass on handling and performance.

It's a question of degree. Is the performance advantage of PCCB's on the Taycan significant? Not really. Is it noticeable to an experienced driver? Probably. Most importantly, Is that increment of performance, whatever it may be, worth the money? That's very subjective. In combination with the cosmetic and cleanliness advantages of PCCB's it was to me. YMMV.

BTW, if I were tracking a car extensively, I would probably choose cast iron rotors over carbon ceramics simply for the replacement cost factor. On a street car, where PCCB's will likely last for the life of the vehicle, the initial expense is easier to justify.
 
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So, you're saying that un-sprung mass has virtually no effect (or "makes very little difference" in your words) on handling, turn in, steering feel or performance? Almost makes one wonder why anyone would bother with lightweight wheels, brakes and suspension components.
Why does everyone take what @f1eng says out of context of the person giving his valuable advice? What he is saying is in the context of a f1 car where everything is already very light weight. He is just saying that the difference between iron and pccb is negligible from a total performance pov. Not that Unsprung weight dosnt matter in general. But I am sure he would agree that in an f1 car the weight saved on the breaks could be used somewhere else to improve performance. So that is why they all use carbon ceramic breaks.
 

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The unsprung mass changes I have tried makes very little difference to wheel load fluctuations (which is the grip determining parameter from the suspension dynamics) even on a light F1 car IME and FYI the rotational inertia is dominated by the tyre because its mass is concentrated in the belt and tread and since the value is determined by radius squared the tyre is the big thing not the brake rotor.

As far as I am concerned the brake choice on a Taycan is for styling not performance, unless you do track days.
The unsprung weight is going to have a greater affect on tire load variation on rougher roads than smooth race tracks. Street tires are also going to experience more load sensitivity than a racing tire due to increased void area (i.e. you're going to have more tire traction with less unsprung wt.). These are all marginal gains, of course and I have no issues with people, including myself, shelling out $$ for marginal gains. It's part of the fun of being an enthusiast.

One other area where CC brakes have an advantage is the consistency of CoF. Having combed through enough friction graphs for traditional pads, I was curious. Pagid has their CC pads Cof plots and they are dead flat. That consistency is definitely noticeable for anyone using their brakes repeatedly at the limit.
Porsche Taycan Nice vid about ceramic brakes 1653683079880

Compare that to typical pads. Anyone who's been on a track with track or race pads knows the feeling when your brakes are cold, or too hot.
Porsche Taycan Nice vid about ceramic brakes 1653683298771

Modulation is less easily quantified, but also an important aspect. Have never tried CCBs but would be curious how they compare. And, as any student of Claude Rouelle knows, the bulk stiffness of the pads (and system) is also critical for driver confidence. Doesn't matter if you have a high friction or heat stable compound, if it feels soft under foot, you lose confidence. That's where driver feedback is more important than data alone. Again, I'm curious is there is any appreciable difference there between iron and CC brakes.
 

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Why does everyone take what @f1eng says out of context of the person giving his valuable advice? What he is saying is in the context of a f1 car where everything is already very light weight. He is just saying that the difference between iron and pccb is negligible from a total performance pov. Not that Unsprung weight dosnt matter in general. But I am sure he would agree that in an f1 car the weight saved on the breaks could be used somewhere else to improve performance. So that is why they all use carbon ceramic breaks.
In addition to weight, the main reason that F1 cars use carbon brakes is for their superior fade characteristics and their performance at very high temperatures.

I don't think I'm taking anything out of context and I appreciate his (and your) POV. The bottom line, though, is that according to the vast majority of sources reducing unsprung weight is beneficial. The only question is how beneficial is it on a car like the Taycan and is the benefit worth the expense of PCCB's. I'm not sure how to quantify either of those two things which is why we can probably argue this subject until the cows come home.
 
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OTPSkipper

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I don't think I'm taking anything out of context and I appreciate his (and your) POV. The bottom line, though, is that according to the vast majority of sources reducing unsprung weight is beneficial. The only question is how beneficial is it on a car like the Taycan and is the benefit worth the expense of PCCB's. I'm not sure how to quantify either of those two things which is why we can probably argue this subject until the cows come home.
You are treating unsprung weight reduction as an absolute, I think. Good engineers don’t do that. Everything is a balance. @f1eng already said that fade is totally controllable with iron brakes with proper airflow. My guess is that the real advantage for f1 is allowing more creative use of that airflow because the breaks don’t need it any more.

As for Taycan, I think you are reduced to the dust argument. Is that worth the bucks?
Sponsored

 
 




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