Porsche Stability Management for DE

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This topic contains 5 replies, has 6 voices, and was last updated by aero0t2 aero0t2 1 month, 3 weeks ago.

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  • #26060

    Larry F
    Participant

    Insert the laugh track from the guys with older Porsches here.

    At my last DE event my instructor asked if I use PSM (stability management) on the track. Up till now, I have used it – possibly influenced by my on track coach in Leipzig when I took delivery of my Macan suggested it was the button to turn off if you wanted to die.

    However, my last DE instructor suggested ultimately more speed was available with PSM turned off. I have seen some comments on other forums discussing rear brake temperatures and PSM, suggesting that the PSM increases rear brake temperatures when it uses the brakes to stabilize the cars. I can see that, and if brakes are being applied, that it would slow things down on the track. So, this brings up the question, at what point does it become advisable to turn the PSM off for DE events?

    #26061
    Wild Weasel
    Wild Weasel
    Participant

    Forgive me for not knowing who you are, but we need a bit more information to really help you answer this.

    If you’re talking about any of the current generation cars (981/982/991.x) then everything I’ve read about this suggests that the PSM is extremely good and that if it’s stepped in to do something, then you’ve already screwed up and should be thankful for the help.

    It does not slow you down.

    I think you might be getting PTV (torque vectoring) mixed into the discussion with regard to rear brake wear. If you’re using PSM so much that it’s causing extra brake heat, then you might just be a bit of a maniac.

    Finally… just my personal stance on this… I’ve NEVER turned off the nannies on the track. The only time I ever had them off was during IDS when the instructor turned them off on the skid pad.

    It seems to me that if you’re good enough to not need them, then they won’t do anything anyway.

    It’s possible none of this applies to some older cars. I have no idea how intrusive or not their systems might be.

    #26062

    Adam Holland
    Participant

    I’ve turned a lot of laps at Mosport with PCA in a 930 street car, a 930 race car, a 964 race car and a lightly modded 2007 Cayman S. So a good amount of experience without any driving aids, and a couple of seasons with PSM fully engaged in the Cayman.

    When driving the Cayman, every time I’ve decided to lift out of the throttle slightly (as I would in one of the air cooled cars) because things were about to go south, the car thinks the exact same thing and beats me by a fraction of a second. So myself and the car are thinking the same thing, at the same time (and the car will always be faster to react). In the aircooled cars I am the input.

    I don’t see the benefit to turning it off, especially for what we are doing. What do you stand to gain vs what you are risking? It hasn’t slowed me down, and usually if you manage to upset the car enough that PSM is engaging then you’ve made a mistake or taken a sloppy line through a corner.

    There is only one place where I can routinely get it to engage and that’s the exit of 5b, but it’s usually just too much steering input on my behalf upsetting the car. Turning it off to gain a small amount in that corner and risk a bigger mistake elsewhere just doesn’t seem reasonable.

    Any Porsche Stability Management system from the last ~15 years or so is very good and not that intrusive. It doesn’t completely sack the car of its power and allows a LOT of room. So I would vote to leave it on.

    • This reply was modified 2 months, 2 weeks ago by  Adam Holland.
    • This reply was modified 2 months, 2 weeks ago by  Adam Holland.
    #26065
    Brian Sullivan
    Brian Sullivan
    Participant

    I read somewhere that Porsche estimated that turning off PSM might gain a few seconds on the Nurburgring in the hands of a very experienced driver.

    I doubt there is much if any gain for most of us racing driver wannabees in DE (and even if there is so what?). I sure wouldn’t turn it off in my car. I only have ever had it engage once on track – during IDS on the development track but the doesn’t mean it won’t save my car or life sometime in the future

    #26066
    andy wright
    andy wright
    Participant

    Interesting Discussion here. This has been the subject of much debate over the years within our Instructor group and other similar DE programmes. The problem we face as instructors is that the “nannies” on newer Porsches are so good, a student will likely never know when they are driving beyond their skill limit, as the car is saving them from themselves. Just because the car can handle it, doesn’t mean you are improving your ability by going faster or braking less/later. Drive smoother to drive more quickly.

    The conundrum is, if instructors turn off the nannies and the student damages their car, or worse, who is liable. That is why as a rule, we do not do this. That being said, I have known instructors (especially in the Green run group) turn off the Stability Control just so a student can feel the car approaching its limits of adhesion. The PSM even when turned off, is still operating in the background and will still intervene if the car is truly out of shape.

    My advice keep the nannies on, but learn to feel when they are operating. That is a good sign you are pushing too hard.

    Andy

    #26187
    aero0t2
    aero0t2
    Participant

    I have a 987.2 Cayman R and like Andy said, you can’t turn off PSM entirely, short of installing a kill switch. It’s always partially on in the background for when you really mess up (although I’ve still spun the car playing around at Cayuga). If you lock up both front wheels in Sport Mode (activate ABS) or one wheel without Sport Mode, it will fully re-engage. That said, from the day I bought the car, I always turn it “off” in the dry. The cars can brake the rear wheels (Automatic Braking Differential) as a way of limiting wheel spin, and it will add extra wear to the pads and rotors. My friend literally cooked a set of rear brakes on a GTR leaving stability control on at Mosport.

    If you have Sport Mode, it will let the car know that you want PSM to intervene less, but in general the car doesn’t know you are tracking it and probably want it to do things that it doesn’t expect to do on the street.

    In other cars, I have specifically felt the stability control cut power going through turn 2. I guess it didn’t like the slip angle. But the last thing you ever want to do is lift in a turn. If I did have to lift anywhere, I’m pretty sure I’d want to straighten the wheel out first and PSM isn’t going to do that for you. In most places, if things are going wrong, more power is going to help more than less power.

    If my rear tires are starting to slip under power going around a corner, I’d rather keep my foot on the power and counter steer a bit than have the car cut power and brake individual wheels trying to bring the car “back under control”. Especially if you have a car on your back bumper who wasn’t expecting you to brake mid corner!

    I don’t think it’s about going as fast as you can, but it is about learning to control your car better. If the computer is constantly cutting in, you’re either asking the car to do things that it can’t, or it doesn’t understand what you are trying to do.

    It’s easy to mash your foot to the floor and let the computer figure it out, but it’s much more rewarding to learn how much throttle you can apply and how quickly you can lay into it.

    I wouldn’t go out in Green will all the aids turned off, but maybe try to turn them off and play around in a parking lot? Maybe once you have the racing line, gear shifts, and entry speeds down to the point that you don’t have to actively think about what you are doing and are laying down consistent smooth laps, it’s time to try turning it off (and take it easier to start with, and work your way back up). Obviously if you are finding that PSM is actually holding you back from reaching your potential, then you know it’s time to turn it off.

    AJ

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