Ozy190

Has anyone seen any kits out there other than the AP racing one in the tracking thread?

I don't think Giro or Surface Transform have come up with anything for the TTS with the larger rotor and the 10 piston caliper?

CDinSing

I have also been checking. I talked to Clark at Apex and he checked his sources. Nada. Also asked Amy at AutoQuest to reach out to surface transforms. Nothing. The large Cayenne sized discs and 10 pot caliper are too bespoke and not enough of us are tracking, small demand signal…

Hinz Motorsport

ST has just taken measurements for the New 992 Turbo S fitments. If anyone is interested we will begin taking pre-orders next week. The more orders we get the quicker they will get made. Please contact me if interested.

Angryinch

Why are the carbon brakes not wanted?

redyps

The surface will deteriorate more quickly than steel and they are way more expensive to replace. By example, all the Porsche cup cars have steel.

CDinSing

For tracking it comes down to disc life and cost to replace. Iron discs are usually heavier but better heat dissipation causing less thermal load on the caliper and fluid, and are 1/4 the cost to replace versus PCCB. ST continuous fiber CCB are about 1/2 the cost and similar weight and slightly better heat dissipation than PCCB. Plus ST can refurbish their discs while our discs cannot be. There is a company in Germany that refurbs PCCB discs but doesn’t yet list 992 TurboS sizes. Will that happen eventually? Maybe, if their tooling can be sized to accommodate them. Heat breaks down the binder in the CC matrix so heavy track use will deteriorate the disc faster than street use where the slow heat dissipation isn’t an issue. So replacement is inevitable if the car is tracked. The big unknown for me is how long will these much larger discs last?

Ozy190

That is a fantastic explanation, also glad to see a fellow track rat with a TTS.
I already have 12+ trackdays on my car, wondering how much I've messed up the CCBs. Its hard to fry them in 2-3 years, but I've heard that once the carbon degradation gets past a certain point - Porsche will not CPO your car (if you plan to sell).

ipse dixit

That's due to BOP and regulations.

Not because of performance and/or cost.

jnolan

small point, but I think those 10 piston calipers first showed up on the Panamera.

What I don’t understand is why Porsche went with bigger PCCB on this model. I don’t think anyone would argue that other 911 models with PCCB were suffering from braking issues. The 991.2 PCCB calipers are awesome, I would buy those rotors and pair with iron discs for track work.

CanAutM3

Regulation are often established to keep costs down.

Further, CCB do not offer braking performance advantages of iron rotors. The only performance advantage would be unsprung weight.

daveo4porsche

and thermal endurance…PCCB's superpowers are:

• lower brake dust (not a concern for tracking)
• unsprung weight
• extreme thermal endurance/capacity

daveo4porsche

replacement cost is about a wash if you can get 5 pad-set swaps for each PCCB rotor - my data from my 2018 GT3 shows that be to a likely outcome if i hadn't made a mistake and let my rear rotors pads wear below 30-40% before swapping

https://rennlist.com/forums/991-gt3-...3-991-2-a.html

the rotor wear rate appears to be on track (no pun intended) to be 4-6 pad sets and then you'll need new rotors - given that you swap steels (at least the factory steels with each pad set) this means PCCB rotors are only swapped once every 5 pad sets (or more) - bringing total cost of 5 or 6 brake jobs inline with steels…

so it's really honestly a YMMV situation - but you don't swap the PCCB rotors as often as you do steels…so the straight cost comparison is a bit harder to work out…no question a set of PCCB rotors cost way more than a set of cast-iron rotors…but PCCB rotors last longer than cast iron rotors even when they are tracked…so....it's all down to the consumption rate.

CDinSing

Dave,

Good input. I assume Porsche went with larger rotors to match the power increase and improve the life beyond what they had with the 991. I used AP J hooks with Ferodo DS3.12 and replaced discs every two pad swaps on my GT3 and RS. I replaced pads at 4mm. At Sebring I would lose 1mm pad thickness per day in front and half that in the rear. That would mean replacing front discs every 16 track days. If I assume 5 pad swaps equivalents, that would be 40 track days for the PCCB discs for me.

Unfortunately I hesitate to make that direct comparison to the GT cars because they require less energy dissipation than the Turbo due to lighter weight, much lower entry speeds and higher apex speeds and energy being related to both mass and V squared. I estimate a 10% increase from weight and 14% from speed over the GT cars. The turbo is just that much faster in a straight line without the aero to carry that to the apex. With 4 fast straights at Sebring per lap the brakes work hard. I am hoping for a PCCB refurb or an ST CCB solution to reduce the cost.

daveo4porsche

yeah - we'd have to track a turbo and then measure the wear like I did for my GT3 - so it's really honestly a YMMV situation…

CDinSing

I only have 4 days on the car and the pads are at 7mm all around. So that seems to be wearing a little more than the Ferodo pads on the GT cars especially in the rear. I am not sure about the need to bed ceramic pads but admit I didn’t do that and probably lost more pad thickness during my first session. So the data is somewhat suspect. I will run the to 4mm and swap.