In October I ran my new (to me) 991.2 manual with SportChron at a HDE at Spring Mountain here with the Vegas PCA. When I entered the track with my instructor with the car in sport for the first lap it got quite squirrelly and lose. I corrected and we were off, but my instructor said let's get the tires warmed up. So we did. I was surprised how far out the system let the rear of the car swing, though. It was not 5 or 10 degrees as I have heard others describe.

As I progressed through the first run session, my instructor gave me thumbs up to select sport plus. In that setting when things were going right I could feel the car dancing on the edge of its traction then progressively rotating and drifting wide when I lifted off on big sweepers so that I used the whole track and was set up to blast to the next set of corners. Every so often I would overcook, and the back slid out significantly and I had to heavily correct. All in all, great day and learned a lot about car and myself, and instructor said I could bump to intermediate green group for independent runs in the last 2 sessions if I wanted. I stayed in the newbie group, though.

Cut to November and I took my car to my independent for tech inspection. He said I had about 40% rear brakes left and if I wanted to run in November I should change them out, as I could use them all up on the track because of the stability control. Seemed like a huge waste to lose 40%. I told him I was running sport plus, which is supposed to greatly reduce the stability control. He said it's still on and how much brakes you use depends how well you drive, implying that a good driver would not be triggering stability control, so therefore wouldn't use the brakes up. He said to turn it all the way off hold the button on the console down for a few seconds. I have not tried that yet on track or street, and I decided not to change the brakes and do the second event because it seemed like a huge waste of money.

Additional fact - I have heard some complain they cannot drift or rotate their cars at all, even in sport plus or with traction control off. My car, even with all systems 100 percent on, will get sideways turning a corner when the tires are cold, and get squirrelly in a straight line under full acceleration (it has a tune allegedly giving 100+ hp) in same circumstances.

So, I am very confused by the whole thing. I would think stability control would kick in and prevent a lot of rotation on those cold mornings, and it doesn't seem to. Sometimes I need a full quarter turn of my steering wheel for opposite lock when the back end comes out. On the other end of the spectrum, I am quite surprised the mechanic thinks I am going to eat up 40 percent of brakes during a HPE even in sport plus. Finally, I am curious if there are separate traction control and stability control systems on my car, and if turning off one affects the other.

I am grateful for any expert input. Thanks!

 

Below 50% pad life, your pads will overheat faster leading to brake fade. If you drive on the track, replacing pads at 50% is just one of the costs.

 

There's a limit to what the computers can do to save you. Cold tires, in the rain, there's only so margin before you go over the limit. Drivers who do something particularly stupid in bad conditions, it's impossible to save. Just physics.

 

What brake pads are you running? If stock, maybe time to upgrade especially in a tuned 991.2. More track focused pads will wear less in a track environment.

 

If you are wearing your rear brakes out faster than your fronts, you are relying a lot on your car to intervene and keep you from going even further out of shape. Turn traction control all the way off (not really all the way off though) and drive. It will be a different experience. When I first starting tracking my 991.2 I would quickly wear out the rears. Now I go through fronts (which is what is really stopping the car) much faster than rears because I am not engaging traction control. I would recommend you use your rear brake wear speed as a learning tool.

If you plan on tracking more, consider learning how to change pads. Worthwhile getting a caliper stud kit, a few tools and tying up the break wear sensors. Once you get good, you can change out pads in 30 minutes.

 

Traction and stability control are two separate functions although performed by the same system. Traction control is wheel spin under power, stability is direction.

The rear brakes will continue to wear even if you turn it off completely as the e"LSD" and torque vectoring use the brakes.

 

Few points:

1) The aids are quite intrusive, and even on a car where it is possible to track it semi hard with them on I routinely hit them on corner exit in my GT4 which is significantly less intrusive than your 992. I generally can drive my GT4 with aids on at 99-101% of the limit and not have the aids engage except on corner exit when I get a little ham footed, or when I induce a little too much weight transfer rotation on corner entry that the car thinks I'm in trouble when I wanted that. In both cases the aids shut down what I'm doing hard like someone hit an undo button. For what you describe you're likely being rough enough with your car you're surprising it, so you're probably driving 60% to 120% which is normal for a new driver to track driving. The aids are definitely there on a normal 911 it sounds like you're probably finding out they can only do so much.

2) Anyone who says they can't rotate a 911 has a fault with their driving and not with the car. I've always found 911s to be very balanced and easy to rotate on the edge with weight transfer. Yes, they have a massive tire out back and a skinny tire upfront, but to rotate one you merely have to just hard brake, turn in, and then a fraction of a second after turn in release the brake. This will lighten up the backend if driven on the edge to the point where it will rotate more than is possible otherwise with aids off. You cancel the rotation by applying the gas to shift the weight to the rear of the car.

3) Personally I would turn the aids completely off at some point as they do more harm than good in the long run. You should not rely on them to save you as you are going to be developing bad habits on the track doing so. This is very apparent by chewing through rear pads. Letting the aids do everything while you just stomp on the pedals and let the car sort it out is not something you want to continue. If you ever drive anything with the aids off you're basically training yourself to crash. I have seen countless people who have thought they were good at driving because they drove an aids heavy car that sorted everything out for them become completely useless in a proper race car without aids. PCA probably is going to tell you to keep the aids on, but eventually you should seek out an instructor that is not going to ridgely adhere to that. There will be parts of pretty much any track where it is safe and actually ideal to exceed the grip of the car to train yourself both how to handle catching a car, and how to seek out the edge of grip and keep it there without exceeding it significantly. One of the schools I teach with we'll take beginners out, sometimes of the first day of the weekend course, and we'll be having them do throttle steer/weight transfer exercises with the goal of eventually losing the back end. When that happens we're teaching them how to catch the car; usually on their 2nd or 3rd time they lose the back end they catch it instantly, and now they know how to stop a car from doing a tank slapper into a wall.

4) I routinely take my brake pads down to nothing. In theory tossing pads prematurely helps with heat, but honestly if that level of heat difference is what makes or brakes your ability to brake, you should be upgrading your pads anyway to a proper track pad. Newbies to track driving also use their brakes significantly more than experienced drivers. You're basically slowing down way too much in corners generating way more heat, yet at the same time going way slower and cooling them down less. I teach at one track that is very hard on the brakes and a lot of my students cook their brake fluid unless tehy have high temp brake fluid. A decent amount get brake fade from running OE or street/track pads. If you continue to drive I would upgrade to a better brake pad; no need for a heavy duty track pad, but a light duty track pad is generally more consistent. low temp friction co-efficients are generally still good too and are often higher than a lot of street pads even when at ambient temps. Even in cold temps their friction co-efficients should still be good for instant bite. I drove one of my street track cars home in -5 degree temps once with medium heat range track pads on. After being on the highway for 20 minutes i decided to do a test and see how good they bit so i stomped on the brakes. Stone cold brake pads in freezing temps and instant bite.

 

I appreciate this feedback.