iron rotors and pads on PCCB setup and ABS
06-06-2024, 06:03 PM
#16
Rennlist Member
I've got a lot of experience with this, testing on both my own car and testing with customer cars.
The 3.12 pad is a high torque pad that takes more finesse on application and release than other choices if one wishes to stay in threshold and out of the ABS. May drivers on street tires (Cup 2s) find it easier to modulate on the 1.11 compound than on the 3.12. Switching your pad compound should be a relatively easy route to help mitigate the issue.
Too many drivers simply default to the highest torque they can find because the internet said so, but those pads are often better suited for race application than for HPDE cars (and drivers). When I raced with slicks I ran a very high torque pad. but now that I am doing HPDE with a street car on 200 TW tires, I find that a lower torque pad helps ensure that the grip of the pad does not over power the grip of the tires, which is usually the limiting factor.
Watch this threshold braking event on the 1.11 compound ask yourself if you really think you need more torque than this?
The 3.12 pad is a high torque pad that takes more finesse on application and release than other choices if one wishes to stay in threshold and out of the ABS. May drivers on street tires (Cup 2s) find it easier to modulate on the 1.11 compound than on the 3.12. Switching your pad compound should be a relatively easy route to help mitigate the issue.
Too many drivers simply default to the highest torque they can find because the internet said so, but those pads are often better suited for race application than for HPDE cars (and drivers). When I raced with slicks I ran a very high torque pad. but now that I am doing HPDE with a street car on 200 TW tires, I find that a lower torque pad helps ensure that the grip of the pad does not over power the grip of the tires, which is usually the limiting factor.
Watch this threshold braking event on the 1.11 compound ask yourself if you really think you need more torque than this?
06-07-2024, 04:25 PM
#17
RS braking performance is pretty mind boggling coming from more normal performance car platforms like M.
Provided you have the tires for it, aero in maximum attack, proper alignment -- considerably deeper into a high speed brake zone, smooth but very aggressive initial application, then the trail is pretty accelerated as well. Overall less time under braking than you're used to. RS returns to equilibrium for turn in so quickly, efficiently. It doesn't respond well to any half hearted braking techniques
Also allow the front axle to work on turn in similar to an M car.
Provided you have the tires for it, aero in maximum attack, proper alignment -- considerably deeper into a high speed brake zone, smooth but very aggressive initial application, then the trail is pretty accelerated as well. Overall less time under braking than you're used to. RS returns to equilibrium for turn in so quickly, efficiently. It doesn't respond well to any half hearted braking techniques
Also allow the front axle to work on turn in similar to an M car.I've got a lot of experience with this, testing on both my own car and testing with customer cars.
The 3.12 pad is a high torque pad that takes more finesse on application and release than other choices if one wishes to stay in threshold and out of the ABS. May drivers on street tires (Cup 2s) find it easier to modulate on the 1.11 compound than on the 3.12. Switching your pad compound should be a relatively easy route to help mitigate the issue.
Too many drivers simply default to the highest torque they can find because the internet said so, but those pads are often better suited for race application than for HPDE cars (and drivers). When I raced with slicks I ran a very high torque pad. but now that I am doing HPDE with a street car on 200 TW tires, I find that a lower torque pad helps ensure that the grip of the pad does not over power the grip of the tires, which is usually the limiting factor.
Watch this threshold braking event on the 1.11 compound ask yourself if you really think you need more torque than this? https://youtu.be/9cv0wkpKycY
The 3.12 pad is a high torque pad that takes more finesse on application and release than other choices if one wishes to stay in threshold and out of the ABS. May drivers on street tires (Cup 2s) find it easier to modulate on the 1.11 compound than on the 3.12. Switching your pad compound should be a relatively easy route to help mitigate the issue.
Too many drivers simply default to the highest torque they can find because the internet said so, but those pads are often better suited for race application than for HPDE cars (and drivers). When I raced with slicks I ran a very high torque pad. but now that I am doing HPDE with a street car on 200 TW tires, I find that a lower torque pad helps ensure that the grip of the pad does not over power the grip of the tires, which is usually the limiting factor.
Watch this threshold braking event on the 1.11 compound ask yourself if you really think you need more torque than this? https://youtu.be/9cv0wkpKycY
06-08-2024, 08:19 AM
#18
Girodisc with DS3.12 or the Pagid equivalent (RSL1) is the go to setup for good reason. Have seen on dozens of track GT cars, GT3's, RS's, GT4's. Good luck sourcing the issue, but it's not incompatibility of pad/disc/software.
06-11-2024, 04:22 PM
#19
Rennlist Member
You left out one important variable - the driver. 3.12 does work very well with the GT ABS system, but it does require a different level of modulation than the 1.11 pad. Especially with a 200 TW tire, When driver's struggle finding the line between threshold and ABS, we often advise to back off the torque on the pad and see if there is a different result. Especially true when the limiting factor is the tires, not the compound of either pad choice.
06-11-2024, 04:25 PM
#20
You left out one important variable - the driver. 3.12 does work very well with the GT ABS system, but it does require a different level of modulation than the 1.11 pad. Especially with a 200 TW tire, When driver's struggle finding the line between threshold and ABS, we often advise to back off the torque on the pad and see if there is a different result. Especially true when the limiting factor is the tires, not the compound of either pad choice.
Today, 01:28 AM
#21
some new data points, but kinda think we have occam's razor here...
TL;DR; my cup2s were probably heat cycled past the point of being useful even though i had a decent amount of tread left.
did a semi-exclusive private day at high plains raceway at june 19th. weather was actually cool, 72F high, today it 97F. got luckily.
new brake pads, switching from cobalt XR1s front and rear to:
immediately the same behavior. on the very first warmup lap even, started talking with folks and my buddy asked me how many heat cycles i had on the cup2s, and i thought, geez probably too many... i went to a porsche car club weekend to get some good driver evaluations from more experienced drivers and while the sessions are not as intense due to number of cars and whatnot, i didn't realize how many heat cycles i actually had on these tires. the tread was still decent since the PCA event wasn't that intense of driving. so i think, i just didn't realize how many heat cycles i had until i went back through my VBOX data and saw that i had ~16 sessions on the tires (PCA weekend and 3 semi-private 8 hour track days), so many sessions per day and decent amount of breaks in between sessions (tires cool down). i think, the problem was the most obvious (hence occams razor) and that the tires were just absolutely heat cycled to hell. lol.
swapped for goodyear F1s i had on another set of OEM wheels and immediately issue was gone and actually posted my personal best lap time at HPR in the 2nd session with the new tires.
F1s performed the rest of the day great. curious how they hold up in the long run, but unfortunately not many (if any) track days for me in july/august.
girodisc gp40s pads were very good. i would say on these 200 treadwear tires, almost couldn't tell a difference with the colbalt XR1s, as i assume the brakes pads are not the weakest link.
planning on testing out the goodyear F1Rs since there is not much other tires for OEM wheels available. i tried the cup2rs on the g80 m3 and they were great for 1-2 sessions and then were absolute toast. total nurburgring hero tire.
TL;DR; my cup2s were probably heat cycled past the point of being useful even though i had a decent amount of tread left.
did a semi-exclusive private day at high plains raceway at june 19th. weather was actually cool, 72F high, today it 97F. got luckily.
new brake pads, switching from cobalt XR1s front and rear to:
- girodisc gp40s fronts (bedded in at track).
- endless me20 rears.
immediately the same behavior. on the very first warmup lap even, started talking with folks and my buddy asked me how many heat cycles i had on the cup2s, and i thought, geez probably too many... i went to a porsche car club weekend to get some good driver evaluations from more experienced drivers and while the sessions are not as intense due to number of cars and whatnot, i didn't realize how many heat cycles i actually had on these tires. the tread was still decent since the PCA event wasn't that intense of driving. so i think, i just didn't realize how many heat cycles i had until i went back through my VBOX data and saw that i had ~16 sessions on the tires (PCA weekend and 3 semi-private 8 hour track days), so many sessions per day and decent amount of breaks in between sessions (tires cool down). i think, the problem was the most obvious (hence occams razor) and that the tires were just absolutely heat cycled to hell. lol.
swapped for goodyear F1s i had on another set of OEM wheels and immediately issue was gone and actually posted my personal best lap time at HPR in the 2nd session with the new tires.
F1s performed the rest of the day great. curious how they hold up in the long run, but unfortunately not many (if any) track days for me in july/august.
girodisc gp40s pads were very good. i would say on these 200 treadwear tires, almost couldn't tell a difference with the colbalt XR1s, as i assume the brakes pads are not the weakest link.
planning on testing out the goodyear F1Rs since there is not much other tires for OEM wheels available. i tried the cup2rs on the g80 m3 and they were great for 1-2 sessions and then were absolute toast. total nurburgring hero tire.
Today, 10:42 AM
#22
Rennlist Member
It's tire grip in relation to your braking power. @jakermc gives a good visual.
Assuming your tires haven't heat cycled out (sounds like they did), you may need a few laps to get them hot and grippy, or you just need to go to a stickier set of tires. RE71RS seem to be a pretty sticky compound that warm up fast, can handle braking power and can be driven too and from the track. Not bad for a 200w tire. Don't know how they perform in the rain.
PSC2s are pretty much street tires. If they behave like the original pilot sport cups, they will need 2-3 laps to warm up and get sticky, and then wear pretty fast. I would get about 8 sessions out of them at the most. Don't know the F1s.
As a side note, check your tire pressures. You may need to start at lower pressures to get to the right target when hot. Over inflated tires give you a smaller contact patch and a boatload of problems.
Good luck with finding the right mix.
Assuming your tires haven't heat cycled out (sounds like they did), you may need a few laps to get them hot and grippy, or you just need to go to a stickier set of tires. RE71RS seem to be a pretty sticky compound that warm up fast, can handle braking power and can be driven too and from the track. Not bad for a 200w tire. Don't know how they perform in the rain.
PSC2s are pretty much street tires. If they behave like the original pilot sport cups, they will need 2-3 laps to warm up and get sticky, and then wear pretty fast. I would get about 8 sessions out of them at the most. Don't know the F1s.
As a side note, check your tire pressures. You may need to start at lower pressures to get to the right target when hot. Over inflated tires give you a smaller contact patch and a boatload of problems.
Good luck with finding the right mix.
