4S Brake upgrade or not..

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JacobDK

JacobDK

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Didn't they downsize the caliper for the coated brakes in 2021 due to supply issue?

I found the standard red brakes insufficient. I had a first generation Audi S7 previous, and the Audi emergency braking performance was significantly better than my 4S.

However, I don't know if it has more to do with the brakes or the car's weight and the timing the friction brakes kicking in.
Don’t know if it was due to supply issues. The 10 puston MY20 was an Akabone caliper and it weighs a lot more than the current 6 caliper set which I believe is supplied by Brembo. With carbon rotors they still use the Akabone - but with the steel rotors i think the weight of rotors and calipers is to heavy in order to make the handling as good as possible. I have the MY20 6 pot version and I does not lack stopping power even when being driven hard on track.
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this article in particular is excellent - but the kicker is at the end of the article and tells you all you need to know…

https://www.roadandtrack.com/car-culture/a10316984/why-braking-is-all-about-tires/
Tyres are important for sure - but tyres are not enough to insure braking performance with repeated braking as on a racetrack. The most important is the brakelines (to steel), make sure rotors can clean brakedust and be cooled and lastly the brakepads (racepads). All of which does not make senseon a road car 😂
 

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I was considering the brake upgrade for my build on the 4S. According to Porsche the regenbraking (up to 265kW) is expected to handle 90% of all braking.. why the upgrade then? Well for me it was due to the coating on the upgraded set which is more ressistant to corrossion. But here is a plot twist. According to the Porsche Denmark Taycan specialist technician the braking system automatically applies the disc from time to time to avoid the corrosion which makes the upgraded kit redundant IMO. Moreover according to him Porsche Service are not expecting disc replacement due to tear/wear but due to age!!
I allready have a race car so the Taycan is my planned as my dayli driver ;)
Any thoughts on the subject?

BB15F211-DC33-4E6C-AC72-39807FADAC78.jpeg
I have a 2021 Taycan 4S with about 10,000 miles on it and with the standard brakes. The braking is exceptional and there is very little brake dust created. I know because I dust the wheels after every use, like I do for all my cars, and there is very little residue. Unless you are tracking the car the upgraded brakes, either the PCSB or ceramics, are unnecessary and a pretty pricey vanity upgrade.
 

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I would like to chip in with two tidbits no one has mentioned. Carbon ceramics don’t have good response when cold, and thus at low speeds require more pressure than steel discs. This however is not relevant in the Taycan, except for the first few minutes, as regen takes care of these stops.

One other factor that has utmost importance is brake fluid. It is meant to be non-compressible and with a high boiling point. The problem is that humidity does find its way into the fluid and water boils at a much lower temperature. That is why brake fluid must be replaced regularly and why it is changed very often in motorsport. Also, normally all high-performance cars use DOT4 mineral based brake fluid. There is also DOT5 silicone brake fluid, often used in racing. It has a much higher boiling point and does not absorb humidity. However it has a slight compressibility factor, although it remains constant for the life of the brake fluid. Both are completely incompatible and one cannot easily replace one with the other without flushing very thoroughly all the components.
 

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I know because I dust the wheels after every use, like I do for all my cars, and there is very little residue.
Now hold on Scott, you aren't getting off that easy. Talk to us about "dust[ing] the wheels after every use". You park the car and take out a feather duster, or do you use a spray? Does it still build up and require a proper wash, but perhaps just over a longer period of time?
 

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we just had this raging debate (again on the Cayenne forum)
  • Tires stop the car - NOT the brakes
  • Tire grip is the limiting factor on stopping distance -not the brakes
  • ABS normalizes all stopping because it keeps the tires/brakes at tire grip threshold limits
  • all Porsche brakes can apply more force than the grip of the tires
  • C&D did a test of identicial porsches (911’s) with identical tires and found stopping distances of the two 911’s to be with in 1 ft of each other - steel vs. PCCB
  • the limiting factor on stopping distance is the maximum deceleration g’s force your tires can generate.
  • no manufacturer makes any stopping distance claims regarding ceramics vs. steel brakes
you can’t stop the car in less distance than the tires will allow - and all porsche brakes can maximize the tire’s deceleration grip.

https://rennlist.com/forums/cayenne-9y0-2019/1266809-build-advice-sought-2022-cayenne-gts.html
https://rennlist.com/forums/cayenne-9y0-2019/1266353-pccb-vs-steel-performance-difference.html

https://www.caranddriver.com/features/a15143696/the-power-to-stop/



https://www.roadandtrack.com/car-culture/a10316984/why-braking-is-all-about-tires/



PCCB’s are good for the following:
  1. lighter
  2. no brake fade ever - not that fade is a problem with porsche steel brakes
  3. no brake dust
  4. better appearance
  5. longer life for street driving
PCCB”s are better brakes in every way -but not in any way you will ever encounter in street driving. For PCCB’s to be measurably better you’d have to be experiencing brake fade in normal driving circumstances - and with Porsche’s excellent brakes that is simply not the case. For street driving it’s very very very uncommon to have any circumstance where the brakes will be stressed or under termal fade - in those conditions the brakes stopping distance is dominated by road conditions and tire grip - the brakes are not the weak link there - the tires are so while PCCB’s are better - their characteristics will not come into play.

PCCB’s are a marketing triumph - they are in fact better, but not in any way you experience in normal street driving or even typical track scenarios for a street car - they are a the gold plated optical cable of the braking industry.
What you write here is correct.
My only correction is that you are using the common mistake of referring to the metal brakes as "steel" when they are normally cast iron, which has better friction characteristics than steel, or did have last time I looked into it.
I may not be up to date there since it is almost 40 years since we stopped using iron discs in Formula 1 and moved over to composites.
The principle reason we went composite was weight and life. Properly cooled cast iron discs did not fade but were prone to cracking. Composites were harder to optimise, particularly early on, because the materials which did not wear out in a Grand Prix distance had a fairly narrow temperature band. Too cold and friction was poor and inconsistent, too hot and the wear was huge but no fade, so a possibility of catastrophic brake failure, if you are a Formula 1 fan you may have seen this in high wear places like Montreal and Adelaide.
They have been sorted for the last 20 years or so now though so easy to exploit nowadays.

The braking distance is exactly the same since, as you write, with adequate brakes the braking performance is entirely determined by the tyre grip.

There is often suggestions that banning composite brakes would improve racing because so many people have the false understanding you are correcting in your post.

I don't consider the carbon ceramics to be a sensible choice for a road car unless one has money to burn and like the look.

The coated brakes may -look- a bit nicer than the standard iron discs too in a 4S but there is no chance they will be better as brakes in road conditions.
 
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Scott Blue

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Now hold on Scott, you aren't getting off that easy. Talk to us about "dust[ing] the wheels after every use". You park the car and take out a feather duster, or do you use a spray? Does it still build up and require a proper wash, but perhaps just over a longer period of time?
No spray, I use a swifter duster and unless you hae been in wet weather it dusts the wheels perfectly!
 
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