PCCB v Steel in 997.2s on track
07-18-2012, 03:31 PM
#1
Drifting
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PCCB v Steel in 997.2s on track
My old girl, Gisele (2010 GT3), had steels. The new girl, Violet (2011 GT3 RS), has PCCBs. First time out on track with Violet, I experienced what I believe folks call ice-mode. I "try" to be progressive on the brake pedal, however there were many times I found no additional stopping power as I pushed the pedal harder after initial application. I had to release slightly and try again. Totally unacceptable. 
This most recent track day, I was experiencing the same problem. The last two sessions, I tried to alter my technique by simply hammering the brakes as hard as I could right off the bat. That actually gave me loads of stopping power :lowdown: , but naturally, I over slowed the car and found it hard to adjust my timing. I'll just need more seat time to experiment to find the optimum timing. Plus, this technique simply goes against my own teachings, in that you need to be progressive in order to get the car to "squat" (instead of tipping onto the nose) so that you have a more stable, in control car that turns in more easily. However, since I was over-slowing the car so much, I didn't get to the point where I needed the car to be stable and in control as it would need to be at a higher entry speed.
Does anyone have experience on track in a 997.2 car (or earlier) with both types? Can you share your thoughts and techniques?
This most recent track day, I was experiencing the same problem. The last two sessions, I tried to alter my technique by simply hammering the brakes as hard as I could right off the bat. That actually gave me loads of stopping power :lowdown: , but naturally, I over slowed the car and found it hard to adjust my timing. I'll just need more seat time to experiment to find the optimum timing. Plus, this technique simply goes against my own teachings, in that you need to be progressive in order to get the car to "squat" (instead of tipping onto the nose) so that you have a more stable, in control car that turns in more easily. However, since I was over-slowing the car so much, I didn't get to the point where I needed the car to be stable and in control as it would need to be at a higher entry speed.
Does anyone have experience on track in a 997.2 car (or earlier) with both types? Can you share your thoughts and techniques?
07-18-2012, 07:20 PM
#2
Race Director
Yep that is a PCCB trait. You can get this on steel brake too but no where near as often.
07-18-2012, 09:42 PM
#3
Rennlist Member
It's really a personal thing. Lots of folks here prefer the linear feel of steel brakes on the track and diss PCCBs mainly due to cost. My own experience is that you get very decent mileage and braking performance for that $8k in option cost (assuming you buy new).
I've criss-crossed different types of rotors over the past couple years. PCCBs on the 997.1 RS, going to Brembo Type IIIs running P50s, RS19s and RS29s. PCCBs again on the 997.2 RS, then experimented with OEM cast iron rotors and RS29s. Ditched those steels in a heartbeat after one track weekend and back to PCCBs since.
There's a DISTINCT pedal feel to ceramics: it starts giving you 40% of the bite with the initial 20-25% of pedal travel. Detractors would use exactly that to discount PCCBs for track use, but I don't see that as a negative at all once you've gotten used to it.
You brake PCCBs in a gradual but firm manner. Use the "40 for 20" to that end and you can be very effective in not upsetting the car or worse, standing it on its nose. Urban myth is that PCCBs stop the car in shorter distance than steels, hence the the "flatout" crowd would have you believe that you brake later with PCCBs. For me, I brake at the same point regardless--it's how DEEP you brake that matters. 20% on the pedal, as soon as weight starts transferring to the front, squeeze on that pedal to 80%. You're very likely done with the "max braking" part of your corner entry before heel-toeing starts. This technique may leave some money on the table, but I'm already getting very competitive laptimes and have another 20% in reserve for late-braking shenanigans and code-brown lifesavers if/when I need it.
For comparison, with steel brakes I've had to go 100% every time and often find myself continuing with heavy braking through the heel-toe phase. There's little more to give at that point. Not confidence inspiring in my book.
Over the course of 15 to 20 sets of P40s I've run, I've only experienced ice mode ONCE, and in that one instance I was sort of asking for it:
- Jabbed those brakes as I went over a crest followed by a right-hander
- Front wheels unloaded when I started braking
- Front locked up briefly, car pushed, ABS kicked in and tires unlocked
- Further brake pressure didn't seem to add to the braking effort; ABS didn't feel active either
- Eased up on the pedal, front regained a bit of traction and I went back at it
In this particular case, the normal input would've been to ease up on the brakes to regain front traction anyways. You may call this "ice-mode", but call this my very own hamfisted entry and braking.
Other than that, my PCCBs have been okay with extensive track use.
Horses for courses, as some would say.
I've criss-crossed different types of rotors over the past couple years. PCCBs on the 997.1 RS, going to Brembo Type IIIs running P50s, RS19s and RS29s. PCCBs again on the 997.2 RS, then experimented with OEM cast iron rotors and RS29s. Ditched those steels in a heartbeat after one track weekend and back to PCCBs since.
There's a DISTINCT pedal feel to ceramics: it starts giving you 40% of the bite with the initial 20-25% of pedal travel. Detractors would use exactly that to discount PCCBs for track use, but I don't see that as a negative at all once you've gotten used to it.
You brake PCCBs in a gradual but firm manner. Use the "40 for 20" to that end and you can be very effective in not upsetting the car or worse, standing it on its nose. Urban myth is that PCCBs stop the car in shorter distance than steels, hence the the "flatout" crowd would have you believe that you brake later with PCCBs. For me, I brake at the same point regardless--it's how DEEP you brake that matters. 20% on the pedal, as soon as weight starts transferring to the front, squeeze on that pedal to 80%. You're very likely done with the "max braking" part of your corner entry before heel-toeing starts. This technique may leave some money on the table, but I'm already getting very competitive laptimes and have another 20% in reserve for late-braking shenanigans and code-brown lifesavers if/when I need it.
For comparison, with steel brakes I've had to go 100% every time and often find myself continuing with heavy braking through the heel-toe phase. There's little more to give at that point. Not confidence inspiring in my book.
Over the course of 15 to 20 sets of P40s I've run, I've only experienced ice mode ONCE, and in that one instance I was sort of asking for it:
- Jabbed those brakes as I went over a crest followed by a right-hander
- Front wheels unloaded when I started braking
- Front locked up briefly, car pushed, ABS kicked in and tires unlocked
- Further brake pressure didn't seem to add to the braking effort; ABS didn't feel active either
- Eased up on the pedal, front regained a bit of traction and I went back at it
In this particular case, the normal input would've been to ease up on the brakes to regain front traction anyways. You may call this "ice-mode", but call this my very own hamfisted entry and braking.
Other than that, my PCCBs have been okay with extensive track use.
Horses for courses, as some would say.
Last edited by CRex; 07-19-2012 at 11:06 AM.
07-19-2012, 05:19 AM
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Drifting
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I'm not dissing anybody, but when you really need the brakes to work, you get into them as hard as possible as soon as possible. Gradually into the brakes is like wheel shuffling - you do it and you get banged over the head with a clip board when you get back.
The proof of this is in the data. Using a grown-up logging system (often Bosch in German development cars), you will see that you will only achieve maximum retardation when you get into the brakes really really fast. When demonstrating, even on public roads and remaining within the law, I always check that the passenger's belt is tight and free running, because they do not realise how severe the retardation is going to be. At 180 mph, you are going 88 yards a second, tapering into the brake pedal is wasting your safety margin. Taper out of the brakes not into them.
The issue of brake balance is important. In most instances the rear brakes as stock, are just around for the ride. Sorting this out when upgrading ALL the brakes is well worth it. The the 'squat effect' becomes apparent. Incidentally, I am not convinced that 50-50 is the ideal front/rear weight balance. There should be a rearward bias, somewhere between 60-40 and 56-44. This way, under extreme braking (with all four wheels doing their share of the work) the car becomes 50-50 balanced as the weight is initially transferred forward and then when wanting to accelerate out of the corner the rear wheels have more weight to allow for early application of power.
BTW, do not brake over crests, do your braking before or after the crest.
R+C
The proof of this is in the data. Using a grown-up logging system (often Bosch in German development cars), you will see that you will only achieve maximum retardation when you get into the brakes really really fast. When demonstrating, even on public roads and remaining within the law, I always check that the passenger's belt is tight and free running, because they do not realise how severe the retardation is going to be. At 180 mph, you are going 88 yards a second, tapering into the brake pedal is wasting your safety margin. Taper out of the brakes not into them.
The issue of brake balance is important. In most instances the rear brakes as stock, are just around for the ride. Sorting this out when upgrading ALL the brakes is well worth it. The the 'squat effect' becomes apparent. Incidentally, I am not convinced that 50-50 is the ideal front/rear weight balance. There should be a rearward bias, somewhere between 60-40 and 56-44. This way, under extreme braking (with all four wheels doing their share of the work) the car becomes 50-50 balanced as the weight is initially transferred forward and then when wanting to accelerate out of the corner the rear wheels have more weight to allow for early application of power.
BTW, do not brake over crests, do your braking before or after the crest.
R+C
07-19-2012, 09:41 AM
#5
I think the above 2 posts have really great information in them and basically agree with everything written. This last weekend driving my pccb brakes with P50s at the mancation stop at Mosport I actually went through some of this and then took steps to 'improve' it - and I also got to drive a 3.8RS with PF08 pads and PF rotors on the road to re-fill the car - the pedal feel is very different - very.
I was having issues coming into Turn 5A - I couldn't get the car to stop - it was working in all other corners but not into 5A - this is a problem as you are doing almost 140mph and you you need very quickly slow down to 60mph - very, very quickly if you are trying to do a fast lap. In this situation, you also have to do a 4th to 3rd downshift. What I was doing was not giving it hard enough pressure in this specific corner, I really though I was, but later as I concentrated on trying to see if I could 'fix' the issue I was able to do so. I have no idea why, but on this specific corner I really had to lean on the brake pedal to get near 100% braking - otherwise I was getting the 40% type as described above - where as in other corners I wasn't. When I looked at my technique, I now realize it was poor as I was heal / toeing as well into 3rd and the 'computer' was calculating that I only desired 40-60% pressure. Because I was chasing Sly around, who had slicks, I didn't want to rear end and kill another of Clarke's cars, I decided that I would 100% concentrate on braking - it worked - I then just h/t a little later and was smoother - issue solved.
So, pccbs, clearly don't stab them, but after initial squeeze to get 100% you really have to get into them to get 100% slowing.
I would then compare this to Randy's car I drove with the PF08 Pads with PF rotors - the pedal feel was fantastic on the street when I drove it to get gas - I personally wish the PCCBs felt like this but they don't - that said it is a feel thing and you just need to find the technique to make them work.
With respect to not braking over hills - clearly this is 100% the preferred outcome - but not always possible - certain tracks require this and the technique is to just anticipate the 'unload' and you have to release 'some' amount of pedal pressure so the car won't trigger ABS mode - it is a very delicate balance but you just have to learn how to do it - anticipate that you may trigger ABS and the car won't like what is happening but keep practicing as you can get good at it - this technique is sometimes required as entry speeds increase into certain types of corners - ask the Mancation crew what they had to do into Turn #2 into Mosport - when you watch their fastest laps you can see that they are all braking over #2.
I was having issues coming into Turn 5A - I couldn't get the car to stop - it was working in all other corners but not into 5A - this is a problem as you are doing almost 140mph and you you need very quickly slow down to 60mph - very, very quickly if you are trying to do a fast lap. In this situation, you also have to do a 4th to 3rd downshift. What I was doing was not giving it hard enough pressure in this specific corner, I really though I was, but later as I concentrated on trying to see if I could 'fix' the issue I was able to do so. I have no idea why, but on this specific corner I really had to lean on the brake pedal to get near 100% braking - otherwise I was getting the 40% type as described above - where as in other corners I wasn't. When I looked at my technique, I now realize it was poor as I was heal / toeing as well into 3rd and the 'computer' was calculating that I only desired 40-60% pressure. Because I was chasing Sly around, who had slicks, I didn't want to rear end and kill another of Clarke's cars, I decided that I would 100% concentrate on braking - it worked - I then just h/t a little later and was smoother - issue solved.
So, pccbs, clearly don't stab them, but after initial squeeze to get 100% you really have to get into them to get 100% slowing.
I would then compare this to Randy's car I drove with the PF08 Pads with PF rotors - the pedal feel was fantastic on the street when I drove it to get gas - I personally wish the PCCBs felt like this but they don't - that said it is a feel thing and you just need to find the technique to make them work.
With respect to not braking over hills - clearly this is 100% the preferred outcome - but not always possible - certain tracks require this and the technique is to just anticipate the 'unload' and you have to release 'some' amount of pedal pressure so the car won't trigger ABS mode - it is a very delicate balance but you just have to learn how to do it - anticipate that you may trigger ABS and the car won't like what is happening but keep practicing as you can get good at it - this technique is sometimes required as entry speeds increase into certain types of corners - ask the Mancation crew what they had to do into Turn #2 into Mosport - when you watch their fastest laps you can see that they are all braking over #2.
07-19-2012, 03:41 PM
#6
Rennlist Member
My old girl, Gisele (2010 GT3), had steels. The new girl, Violet (2011 GT3 RS), has PCCBs. First time out on track with Violet, I experienced what I believe folks call ice-mode. I "try" to be progressive on the brake pedal, however there were many times I found no additional stopping power as I pushed the pedal harder after initial application. I had to release slightly and try again. Totally unacceptable.
This most recent track day, I was experiencing the same problem. The last two sessions, I tried to alter my technique by simply hammering the brakes as hard as I could right off the bat. That actually gave me loads of stopping power :lowdown: , but naturally, I over slowed the car and found it hard to adjust my timing. I'll just need more seat time to experiment to find the optimum timing. Plus, this technique simply goes against my own teachings, in that you need to be progressive in order to get the car to "squat" (instead of tipping onto the nose) so that you have a more stable, in control car that turns in more easily. However, since I was over-slowing the car so much, I didn't get to the point where I needed the car to be stable and in control as it would need to be at a higher entry speed.
Does anyone have experience on track in a 997.2 car (or earlier) with both types? Can you share your thoughts and techniques?
This most recent track day, I was experiencing the same problem. The last two sessions, I tried to alter my technique by simply hammering the brakes as hard as I could right off the bat. That actually gave me loads of stopping power :lowdown: , but naturally, I over slowed the car and found it hard to adjust my timing. I'll just need more seat time to experiment to find the optimum timing. Plus, this technique simply goes against my own teachings, in that you need to be progressive in order to get the car to "squat" (instead of tipping onto the nose) so that you have a more stable, in control car that turns in more easily. However, since I was over-slowing the car so much, I didn't get to the point where I needed the car to be stable and in control as it would need to be at a higher entry speed.
Does anyone have experience on track in a 997.2 car (or earlier) with both types? Can you share your thoughts and techniques?
what tyres are you running on Lar?
