I am currently running Pagid RS29 on all four corners but disc temperatures (measured with fluke thermometer) and car behavior are telling me the front brakes are working much harder than the rear so I would like to try dialing a little more bias in the rear.

Since the 997 doesn't have a bias adjuster the obvious way to do this would be to use different pads F/R. Is there anyone running RS29F and RS14R? If so, I would be interested in hearing what your experience is with this combination.

Any comments welcome,

T.

 

if you want noticably more bite in rear - put there pfc01 pads. but they are eating rotors much faste than rs29.

 

Really just curious, T, but I have to ask: did you remove the anti-lock system for your tracking? Our 997's have four-channel bias adjustment in real time unless you've found a way to disconnect it. When that's working, the fronts always dissipate more energy than the rears because of weight transfer, and unlike cheaper systems ours doesn't block pressure when one wheel reaches threshold, or even one axle. It just holds steady on the ones that reach threashold and keeps adding pressure to the others until they all pull at their limit. (Subject to stability intervention, but that's a separate issue.)

As a matter of fact, I'm pretty sure I read that once ABS engages, if you're not pressing the brake pedal hard enough to reach threshold braking on one end or the other, then the system internally boosts line pressure until it can achieve that.

With that system in place, you can change pads all day long with no effect. (Except to change the onset of fade in repeated hard stops if some pad choices are suboptimal.) What I really mean is that tires become the limiting factor in a given stop, not the brakes. The bias is balanced in real time between all four corners. It might be an interesting experiment to try putting a super grippy compound at the back just to see what happens, but I'm afraid we wouldn't like the effect on handling in other ways.

Gary

 

I assume you are running with PSM "off". If not, give that a try first. Best,

 

Gary,

You do bring up a very good point and I had not thought about that... I rarely run into ABS at the track so I am not sure what this would mean for my driving... AFAIK, each pad compound has a certain curve of responsiveness; some have better initial bites, some are more linear, some perform better when really hot, etc. I guess what I am trying to say is that I would like a pad in the rear that has maybe a steeper initial bite than the fronts so when I am doing threshold braking (before ABS) I get a little more bite in the back than in the front.

Let me ask the question another way and give you more data... With r-compound tires, suspension adjustments, sway bar adjustments, and alignment, I think the car is now pretty neutral on a "classic" corner where I brake before turn in, do maintenance throttle in the first half and accelerate after the apex. So everything works like it is on rails _except_ for trail braking... When I enter corners where I try to trail brake, I get definitive understeer. That seems to indicate to me that the front tire patches are doing too much braking and do not have enough left for turning. So if I could transfer some of that braking in the back, I would be golden. Or am I getting this wrong? Any advice will be appreciated.

Or maybe I should just brake all out, all the time .

Yes, I tried PSM off but that really did not change the braking behavior. While on that subject, one thing that I found to be very interesting on my 997.2 is that on my 996 PSM was very annoying when I left it on at the track, but on the 997.2, if I forget to turn it off, it rarely hinders what I am trying to do. Quite frankly, I see the little PSM light flashing but I can't really feel the effects.

Thanks for all the help,

T.

 

I agree. On our dot twos, the stability management is only helpful when it's noticeable at all. I looked it up once. We have something like step 8.0 of the control computer and firmware, while the 996 has a much earlier stepping, something like 5.3 I think it was. Whatever the details, the result is very satisfactory.

I sent you a private message with details about trail braking technique.

Gary