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My experience tracking the car with PCCBs wasn't excessive rotor wear in the front but in the rears. Anyhow this setup works great if you don't want to worry about wearing out your PCCB rotors.
Got the measurements back regarding pccb’s. Without going into a lot of detail the dealer said my brakes have another 80k miles on them. Pads are basically new, and the rotors have very little wear. That is after 23k miles, and two light track days.
Got the measurements back regarding pccb’s. Without going into a lot of detail the dealer said my brakes have another 80k miles on them. Pads are basically new, and the rotors have very little wear. That is after 23k miles, and two light track days.
That’s good to know, but essentially if you don’t damage the rotors by letting the pads get too worn, you’ll probably get over 100K street miles out of the CCM rotors, if not more. It’s the heat generated at a road course let markedly reduces the life of the rotors.
I'll concede to that point lol. I know a good deal of Porsche's typical 991.2 Carrera owners, and most of them don't have the confidence to push the car on the street to more similar to track conditions. I'm sure you are correct in that when pushed hard on the street, they will begin to have similar effects to those experienced under track conditions especially if they have stock pads and rotors. Shooting you over a PM now, I'd love to chat with you a bit more at length on something we're working on.
Sorry we missed each other on Thursday. And I'm nowhere (!) near comfortable to push a car on the street the way I might be on a track (closer to absolute limits, riding out understeer, managing the back end, etc). I don't know how much you get to play on mountain roads in FL, but they present a different challenge to brakes: Instead of red hot slowing from ultra-high speeds before getting big mph to cool again, they get pounded and pounded at relatively low speeds and rarely if ever really get a chance for 80-120 mph cooling. Track use also seems to burn caliper paint, something I have never seen on the street. I'd love to know why.
But one thing seems certain: The base 991.2 brakes get too hot on mountain roads, and the 991.2 S/GTS brakes get too hot on track—at least with Mike at Sebring. Will be interesting to see who comes up with the smartest way to address it. Porsche's calipers don't look wimpy in either base or S/GTS form, so I wonder if larger front (and rear?) rotors, adapters to move the calipers to accommodate said rotors, and upgraded cooling (ducts, deflectors, etc) would be enough?
John at AutoQuest and/or Racing Brake....My 2017 Carrera GTS needs brake help badly.....the front caliper accepts 991 GT3 pads for the 350mm GiroDisc rotors and the GiroDisc I’m using has increased the rear to 350mm rotors but still has to use a Special Carrera S/GTS size pad due to the caliper I think...but I just saw a post above show gt3 and s/GTS pads marked in a rear caliper??
I tried Ferodo DS2500 and DS1.11 pads and they really don’t work well. The 2500 basically melted and fell off due to heat at Sebring in 2 days leaving lots of pad build up on the rotors and the 1.11 pads ate the crap out of the rotors in 2 days and the pads wore out too getting too thin and transferring heat from the thin pad material to the calipers.
My GiroDisc Rotors have probably 2-4 days left...but I’m totally lost on what pads to use....seems like Pagid RS29 Yellows is all that’s left...maybe Race Technology RE10pads?.....HELP ME !!! I want to get back on the track.
Based on your comments above, your issue is not your pads. We have tons of guys with 991 GT3's, Turbo's, etc. running Ferodo DS1.11's on the hardest tracks in the country, and they're getting great wear rates out of them. I think OrthoJoe and friends in Cali are getting 25+ days out of a single set on his 991 GT3 and 981 GT4. The Ferodo DS2500 is more of an autoX/street pad for a 991 GTS. They're only good as a full race/track pad on a lighter, slower car like a BRZ or Miata. I'm not at all surprised that you melted them on the track on your car.
Are you running any type of brake ducts?
Have you taken disc and caliper temperatures?
Without any type of concrete data, it's hard to assess the precise problem. That said, it sounds like you're definitely putting too much heat into your current discs. That means you either need more/proper cooling air, and/or more efficient discs. When you bring your disc temps down, everything else 'downstream' of the discs runs cooler. Cooler discs lower pad temps, which lowers caliper piston temps, which lowers caliper body temps, which lowers brake fluid temps. Everything will last longer, not burn up so quickly, and won't be as prone to pad fade (pedal stays hard but car doesn't slow) or fluid fade (pedal goes soft to the floor).
Keep in mind, that with discs, bigger isn't always better. You only want discs that are big enough to get the job done. Anything larger than required is just dead weight to drag around. A properly designed, high-vane count racing disc is typically far more efficient than a larger OEM style disc (many times pillar vane). My guess is that the Girodiscs currently on your car are a 48 vane design, and probably don't flow a tremendous amount of air. It sounds like you're pouring too much heat into them, and not enough air. It won't matter what pad you drop on top of them. If the discs can't adequately absorb and shed the heat, everything is going to get heat-soaked and burn up. Without swapping out other components, a properly implemented cooling solution could make a significant difference. The problem with road cars is that it can be challenging to get enough air to the proper area of the disc. A poorly implemented duct setup can actually cause more problems than it cures. We've seen this on many customer cars over the years....ducts that don't draw air from a good location on the front or under the car, ducts that dump air onto the face of the disc rather than into the center, duct plates that hold heat against the inner disc face...all sorts of problems. So in summary, ducting isn't an easy solution, but if done right it can be a reasonably priced and reasonably effective solution.
But one thing seems certain: The base 991.2 brakes get too hot on mountain roads, and the 991.2 S/GTS brakes get too hot on track—at least with Mike at Sebring. Will be interesting to see who comes up with the smartest way to address it. Porsche's calipers don't look wimpy in either base or S/GTS form, so I wonder if larger front (and rear?) rotors, adapters to move the calipers to accommodate said rotors, and upgraded cooling (ducts, deflectors, etc) would be enough?
In terms of bolting on much larger discs or calipers from other trim levels, you need to be careful when doing so. For a very long time we've seen many in the Porsche world blindly bolting on the largest Porsche calipers and discs they can find onto their car. It's a potential recipe for poor performance. Assuming your brake master cylinder isn't changed, any change in disc diameter or caliper piston size changes the brake torque output on that end of the car. A change to any one of those components, without the proper corresponding change to the others can result in ABS intervention problems, poor brake pedal feel, and/or longer stopping distances.
A proper brake solution must be thoroughly considered and properly realized, and that is exactly what we're currently doing in the Porsche market. We've done so in numerous other platform markets. A proper brake kit not only provides enough heat capacity, it is properly integrated with all of the other brake system components. We just released complete Essex Designed AP Racing Competition Brake Kits for the 981 and 718 Cayman. We want to develop a similar system for the 991 GTS and S. We just need to find a car to measure. Our 718 system very well may be a proper fit for the car, but we need to verify that.
Front 718 system: https://www.essexparts.com/essex-des...1355mm-981-718
Rear 718 system: https://www.essexparts.com/essex-designed-ap-racing-radi-cal-competition-brake-kit-rear-cp9451-34028-987-981-718
Track use also seems to burn caliper paint, something I have never seen on the street. I'd love to know why.
Calipers can hit temps of 500F on the track (which is way to hot). Acceptable caliper temps on track are in the sub-400F range. On the street, they're going to be far less than that. Paint and powder coat don't shift color until they get up into the several hundred degree range. That's why they stay looking nice on the street, but start turning all sorts of crazy colors when they see track use.
__________________
'09 Carrera 2S, '08 Boxster LE (orange), '91 Acura NSX, Tesla Model 3 Performance, Fiesta ST
Jeff Ritter
Mgr. High Performance Division, Essex Parts Services Essex Designed AP Racing Radi-CAL Competition Brake Kits & 2-piece J Hook Discs Ferodo Racing Brake Pads Spiegler Stainless Steel Brake Lines
704-824-6030 jeff.ritter@essexparts.com
^yes, I've found the ds1.11 to be rather easy on rotors. When coupled with the AP rotors I was getting 30+ days out of the front rotors. Contrast with using endless me20 pads and the ap rotors were getting 20+ days out of them. Stay away from pfc08. Those will destroy rotors. I used to run them with Brembo type 3 rotors and the rotors would be dead in less than 10 days while the pads only 1/2 worn.
Me20 and ds1.11 front pads usually last me about 7 days.
^yes, I've found the ds1.11 to be rather easy on rotors. When coupled with the AP rotors I was getting 30+ days out of the front rotors. Contrast with using endless me20 pads and the ap rotors were getting 20+ days out of them. Stay away from pfc08. Those will destroy rotors. I used to run them with Brembo type 3 rotors and the rotors would be dead in less than 10 days while the pads only 1/2 worn.
Me20 and ds1.11 front pads usually last me about 7 days.
Thanks for the clarification Joe!
Originally Posted by TRAKCAR
Jeff and Joe,Keep in mind CA tracks aren't like Sebring..
Agreed! I lived in Cali for 5 years and drove a number of the local tracks in that region. Prior to that I lived in NJ and drove the NE tracks (Watkins Glen, Limerock, Pocono), and now I'm in the mid-Atlantic (VIR, Road Atlanta, CMP)....I believe I've driven about a dozen total over the past 20 or so years. Some of the most brutal tracks on brakes based on servicing customers (both pro and amateur) are Watkins Glen, Road America, and Sebring. The worst tend to have long, fast straights followed by slow corners. Slowing from a higher speed pours more energy into the brakes. 160-80mph stops are far harder on the brakes than 90mph-10mph stops, even though you're still scrubbing 80 mph. The discs are spinning so many more times per second, and you're converting much more kinetic energy into heat. Many of the Cali tracks aren't too terrible on brakes, although the Roval at Cal Speedway can be tough because you head into the infield at such a high speed and stand on them for quite a while.
With all the talk about getting different readings when measuring the PCCB rotors off the car I got intrigued. So this weekend I removed my left-rear rotor off the car and brought it to the dealership for measurement. They already measured my rotors twice before, but always while mounted on the car. The previous data showed my rear rotors had significantly more wear compared to the fronts, so I was fully expecting to have to transition to Girodisc in the next couple of weeks. Let results speak for themselves! After remeasuring my LR rotor it pretty much looks like new! The tech measured it multiple times, even holding the rotor in the air. Now I want to remeasure the others as well!
With all the talk about getting different readings when measuring the PCCB rotors off the car I got intrigued. So this weekend I removed my left-rear rotor off the car and brought it to the dealership for measurement. They already measured my rotors twice before, but always while mounted on the car. The previous data showed my rear rotors had significantly more wear compared to the fronts, so I was fully expecting to have to transition to Girodisc in the next couple of weeks. Let results speak for themselves! After remeasuring my LR rotor it pretty much looks like new! The tech measured it multiple times, even holding the rotor in the air. Now I want to remeasure the others as well!
I got much lower numbers on my rears, too, again measured while on the car. This just confirms that pccb’s in these cars last a long time.
With all the talk about getting different readings when measuring the PCCB rotors off the car I got intrigued.
After remeasuring my LR rotor it pretty much looks like new!
The tech measured it multiple times, even holding the rotor in the air. Now I want to remeasure the others as well!
Just to be clear and because I'm a bit lazy: When the PCCB's are measured on the car you get a different result then when measured off the car?
02-02-2018, 07:52 PM
