PCCB out braked the steels last night on 5th gear.

PCCB out braked the steels last night on 5th gear.

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Twinfan

4,459 posts

53 months

Friday 15th November 2019
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LennyM1984 said:
I get that the PCCBs are bigger and 6 pot but doesn't the basic conclusion stack up? ie. On a like for like basis (same sized discs, same "strength" calipers) would the carbon-ceramic discs offer no benefit? This is a genuine question and not a smart arse one before you all jump on me.
Tyre grip is the limiting factor in outright braking performance, and both steels and PCCBs will overpower the tyres. In a single stop there would be no difference in a like-for-like test.

Like-for-like, PCCB discs are 50% lighter so there are handling/steering advantages due to the lower unsprung weight. Whether that's noticeable on a trip to Tesco and back is debatable but on a race track you'd notice it

As for heat dissipation, the PCCBs would perform better the more back-to-back-stops you do, but who does non-stop 0-100-0-100-0 etc runs? On a track the discs would cool enough between applications and on the road they'd never get hot enough for it to be an issue.

LennyM1984 said:
What is the reason for most people preferring steel brakes (apart from the obvious cost one)?
Initial cost, replacement cost of discs and pads plus personal preference for pedal feel and travel I suspect.

Porsche911R

Original Poster:

18,241 posts

214 months

Friday 15th November 2019
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Slippydiff said:
poppopbangbang said:
Porsche911R said:
Higher up the racing tree they do use carbon disks.
They are completely different to the carbon ceramics found on road cars though. A modern carbon/carbon brake package can't really be compared to what is used for a road application as they are leagues apart in weight, performance and technology and have more in common with what is on commercial airliners than road cars.
Shhhhhhh, don't say that, Mr Demon thinks just because he's bolted a couple of Porsche M/Sport parts and a noisy/lighter exhaust on his car, he's now swanning around in a road going Cup car ...
I hate race cars for normal use so quite funny you should say such ;-)

I am the biggest poster saying road cars make bad track cars and visa versa.

I'll take heated seats and LED lights and lift thanks.

Digga

28,951 posts

232 months

Friday 15th November 2019
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Porsche911R said:
On the contrary , PCCBS have always been bigger and again are bigger in the GT3 models.
Unless, that is, you switch out PCCB discs for non-OEM Alcon steels. wink

Twinfan

4,459 posts

53 months

Friday 15th November 2019
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TimoMak said:
You clearly didn't watch it, see the bit at the start with the blowtorch.
Materials affect heat dissipation, yes of course. Would steel brakes fare better if they're a lot bigger? It's a combination of material used and size.

Porsche911R

Original Poster:

18,241 posts

214 months

Friday 15th November 2019
quotequote all
Digga said:
nless, that is, you switch out PCCB discs for non-OEM Alcon steels. wink
sadly at that size the 420mm steels would weight just too much and be a disadvantage :-)

isaldiri

5,088 posts

117 months

Friday 15th November 2019
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Twinfan said:
Indeed. Comparing a GT car on steels vs PCCBs would be much more informative, although even then:

Steel: 380mm front and rear
PCCB: 410mm at front and 390mm at rear

So PCCBs always have a size advantage within the same model.
But they have to given carbon ceramic has much less heat capacity per unit mass than iron... Porsche once upon a time had ceramics about the same size as the steels and that didn't end too well....

On a gt car where iirc the calipers are the same ie pad clamping force/area are equal, the difference in performance isn't going to be there. In any case even if tyre grip wasn't the limiting factor, one has a far greater choice of pads for iron brakes if one really wanted to try to add more braking capability.

Milnsey

144 posts

169 months

Friday 15th November 2019
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Twinfan said:
Initial cost, replacement cost of discs and pads plus personal preference for pedal feel and travel I suspect.
In my experience PCCBs have been cost neutral as no biennial replacement of steels due to “corrosion of inner surfaces sir”
That was the main reason for me speccing them. Not yet had to replace pads or discs yet so cannot comment on that point.
However other advantages for me are improved feel and travel, no brake dust , and they fill out the 20 in wheels somewhat more convincingly

Shaoxter

3,479 posts

73 months

Friday 15th November 2019
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Twinfan said:
TimoMak said:
The point made was nothing about the size of brakes (some people on here appear obsessed with size for some reason...), but the reduction in their effectiveness over time and use over several runs of heavy braking due to fade.
But do you not think that heat dissipation, and therefore fade resistance, is related to brake disc and caliper size in some way?
The test wasn't "do equivalent sized carbon ceramic brakes perform better than steels", it was "do the carbon ceramic brakes option offered by the manufacturer perform better than steels"

MDL111

4,083 posts

126 months

Friday 15th November 2019
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JulierPass said:
Porsche911R said:
Slippydiff said:
And ?
95% people here say zero advantage because AP from Porsche does not talk about them when he does his cars chats.

Even the racers here say no such advantage, and thus every one falls in line with miss info.

I have always said their was an advantage and not just for repeated stops.

2 cars tested results are black and white to see.

16 foot after 1 stop, 100 feet after 10 stops.
I haven't seen the article as I don't watch 5th gear. However, there is a reason why all of the factory built Porsche Cup Cars and R's have steel brakes. If the advantage was as pronounced as your post suggests then the race would come with ceramics from the factory.
Doesn’t the RSR come with ceramics?

Could it be cost considerations for the Cup and rules for the R ( GT3 rules)

As an aside a Ferrari Challenge car runs ceramics while the GT3 car runs steels

Edited for forgotten word

Edited by MDL111 on Friday 15th November 17:43

PS2018

252 posts

22 months

Friday 15th November 2019
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having read some scare stories about the accidental ease with which one can write off a pccb disc, if one is on a track day in a PCCB equipped car and has an excursion into the gravel (which then finds its way in between the disc and pad surfaces) is that the end of the fun for the day unless eg all wheels removed and discs and calipers/pads thoroughly cleaned?

isaldiri

5,088 posts

117 months

Friday 15th November 2019
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MDL111 said:
Doesn’t the RSR come with ceramics?

Could it be cost considerations for the Cup and rules for the R ( GT3 rules)

As an aside a Ferrari Challenge car runs ceramics while the GT3 car runs steels
Nope the rsr runs iron brakes. No proper racing car competing in any series outside of challenge uses ceramics.

Supercup long ago ran ceramics iirc but the costs were astronomical and basically no one thought it was a good idea to continue running them.

MDL111

4,083 posts

126 months

Friday 15th November 2019
quotequote all
isaldiri said:
MDL111 said:
Doesn’t the RSR come with ceramics?

Could it be cost considerations for the Cup and rules for the R ( GT3 rules)

As an aside a Ferrari Challenge car runs ceramics while the GT3 car runs steels
Nope the rsr runs iron brakes. No proper racing car competing in any series outside of challenge uses ceramics.

Supercup long ago ran ceramics iirc but the costs were astronomical and basically no one thought it was a good idea to continue running them.
My bad - but the cost argument might hold up then?
I’d obviously prefer steels for exactly that reason

isaldiri

5,088 posts

117 months

Friday 15th November 2019
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MDL111 said:
My bad - but the cost argument might hold up then?
I’d obviously prefer steels for exactly that reason
Given the running costs of GT3 nevermind GTE, I rather doubt cost was the primary reason! biggrin

MDL111

4,083 posts

126 months

Friday 15th November 2019
quotequote all
isaldiri said:
MDL111 said:
My bad - but the cost argument might hold up then?
I’d obviously prefer steels for exactly that reason
Given the running costs of GT3 nevermind GTE, I rather doubt cost was the primary reason! biggrin
You might have a point there smile

Koln-RS

2,915 posts

161 months

Friday 15th November 2019
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Back at the time, over 10 years, Geoff Turrall at Porsche, said that the cost difference in Supercup was actually quite marginal in view of the extended longevity. And that was with earlier derivatives.


cayman-black

8,511 posts

165 months

Friday 15th November 2019
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Funny all those saying they prefer steels, yet the GT cars without PCCB,s are cheaper and hang around longer, strange.

MDL111

4,083 posts

126 months

Friday 15th November 2019
quotequote all
cayman-black said:
Funny all those saying they prefer steels, yet the GT cars without PCCB,s are cheaper and hang around longer, strange.
On a road car I prefer the ceramics, but if I bought say a Challenge car I would very likely change them for steels purely for cost considerations

Taffy66

3,294 posts

51 months

Friday 15th November 2019
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Twinfan said:
TimoMak said:
The point made was nothing about the size of brakes (some people on here appear obsessed with size for some reason...), but the reduction in their effectiveness over time and use over several runs of heavy braking due to fade.
But do you not think that heat dissipation, and therefore fade resistance, is related to brake disc and caliper size in some way?
As a direct replacement for Steels the PCCbs need to be bigger in diameter due to the different characteristics between the two materials in the way they handle heat and brake..I much prefer the initial bite and feel of PCCBs although i accept this is purely personal.

isaldiri

5,088 posts

117 months

Friday 15th November 2019
quotequote all
cayman-black said:
Funny all those saying they prefer steels, yet the GT cars without PCCB,s are cheaper and hang around longer, strange.
that's mainly a UK thing only. in Germany where the gt cars are generally used on track a hell of a lot more, steel brakes are very much the norm there irrespective of the so called performance advantage claimed by some....

People can get overly hung up with their choice of brake material anyway imo. Both work and if you strongly prefer one good for you but there's no need to constantly trumpet it as the best thing ever (usually on their car which is also the best car ever....)

Taffy66

3,294 posts

51 months

Friday 15th November 2019
quotequote all
MDL111 said:
isaldiri said:
MDL111 said:
Doesn’t the RSR come with ceramics?

Could it be cost considerations for the Cup and rules for the R ( GT3 rules)

As an aside a Ferrari Challenge car runs ceramics while the GT3 car runs steels
Nope the rsr runs iron brakes. No proper racing car competing in any series outside of challenge uses ceramics.

Supercup long ago ran ceramics iirc but the costs were astronomical and basically no one thought it was a good idea to continue running them.
My bad - but the cost argument might hold up then?
I’d obviously prefer steels for exactly that reason
I suspect a major reason PCCBs are not used for racing is the inability to carry out cooling down laps at the end of a track session..Cooling PCCBs down after a session on track is essential otherwise the Carbon within the PCCBs will simply disintegrate when stopped when hot.