which comes first? a 981 somewhere near the limit...or not

Pedro, et al...

almost a year now into that delicious creation that is a 981 S it's high time i understood something i currently do not...buying the car off the showroom floor i was inheriting the specification dreamed up by a sales manager, not by one who enjoys driving hard...so in regard to the options included that i assume relate to some extent to handling in its general sense i've just got the standard 'enhanced' PSM, ASR but nothing else.. PDK, Sports Chrono...car usually in 'Sports' mode...

a hypothesis then...assume an entry into a high speed l.h. sweeper where you go in at 100, drop downhill at that speed then suddenly have to go right then left again to exit, uphill, all at about the same speed...forty nine times out of fifty all is serene, magnificent...on the fiftieth, maybe 105 at the moment of transition left to right, there is the slightest of judders from somewhere and a flashing icon shows on the dash...it's all over in a fraction of a second, normal service is resumed, and i haven't the slightest idea what was going on in the 'boffin' department nor did i have the time or inclination at that moment to know what light it was or what it meant though the car never moved as far as i was aware...

so what was that all about? was that PSM doing its job protecting me from myself which is exactly what i would want it to do? If so what are its limitations in this context - 110? 115? And if i had the other handling options also how would their presence have added even more security and in what form?

finally then the over simplistic question that just has to be asked...if there's a corner on your daily drive home that you now know well enough to take at 100 what would happen for the sake of argument if you were to increase that speed by one mile an hour each week? and when whatever it was that did happen eventually happened would it be bells and whistles all going off and saying naughty boy? or would you be in the adjacent field before they could talk to you? which would come first?

theoretically of course, this is all theory, mostly...

I can't address your questions, and maybe it's not my place to offer advice, but I'd caution you about your hypothetical drive home. On public roads, if you get to the point that you and your car end up in a field, it's likely not the same thing as on a track with plenty of run off. In public spaces the run off area maybe occupied by a tree. Or, if the road has a curb, you are less likely to slide into a field than to roll into it. Ever see a curb at a track? There's a reason for that, and that is where it is safer (but not guaranteed safety) to test the limits of any car. Good luck.

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Bobtesa
I can't address your questions, and maybe it's not my place to offer advice, but I'd caution you about your hypothetical drive home.

Yea, that was an interesting read until i realized you were not on a track. Really bad idea IMNSHO.

See me answer in line with your question.

Grant

(packing to leave for NJMP)

Grant

gee-lenahan-at-gee-mail-dot-com



Edited 1 time(s). Last edit at 04/27/2014 10:26AM by grant. (view changes)

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Bobtesa
I can't address your questions, and maybe it's not my place to offer advice, but I'd caution you about your hypothetical drive home. On public roads, if you get to the point that you and your car end up in a field, it's likely not the same thing as on a track with plenty of run off. In public spaces the run off area maybe occupied by a tree. Or, if the road has a curb, you are less likely to slide into a field than to roll into it. Ever see a curb at a track? There's a reason for that, and that is where it is safer (but not guaranteed safety) to test the limits of any car. Good luck.

+1. Way yoo many variables to try this on the street, not the least of which are your fellow motorists that may have the bad fortune of crossing your path.
As others have suggested, save this for the track; after a few DEs you'll realize how reckless this sort of behavior might be on the streets.

Well, it does sound like you're enjoying your 981. They are fabulous cars.

I go along with what Bobtesa says about driving on public roads at hypothetical limits. On the track it's more controlled. You know that there's not going to be a car coming the other way around the corner, for instance. You've got run off areas and there's also help on hand if something does happen.

I don't think that you can put a specific number on any limit in a corner since driving conditions change from one time to the next. Maybe the road is colder, some dirt / gravel / water etc that wasn't there before are on the curve, they all will have an effect on what the actual limit is at that instance.

As to the light you saw flashing (hope you were watching the road too) it was most likely the PSM, indicating that brakes had been applied to one wheel to steady the car to keep you out of that field you mentioned. That's the function of PSM.

As to the bells and whistles going off and ending up in an adjacent field time line. Just ask yourself how much time you had to react to the PSM light flashing on your dash. That should give you a pretty good idea.

My other question is, if all the bells and whistles do go off. Exactly what should you do?

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Guenter in Ontario


I don't think that you can put a specific number on any limit in a corner since driving conditions change from one time to the next. Maybe the road is colder, some dirt / gravel / water etc that wasn't there before are on the curve, they all will have an effect on what the actual limit is at that instance.

Exactly right. You cannot find a number. You can only play with incremental changes with the road, tires, ambient environment etc all under ideal circumstances.

Most track spins happen on cold tires. The difference in both grip and abruptness is HUGE. People are pretty ignorant of these differences.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

So what was that all about? was that PSM doing its job protecting me from myself which is exactly what i would want it to do?

GFL --> My guess is, yes. On track PSM stands for "please save me". Its interesting to see people graduate from modern cars to minimalist older cars and have several holy shit moments. Likely, as the car began rotation PSM kicked in and saved a spin (or slide). Note that my cars have none of this - just ABS. And my first track outing without ABS was an eye opener.

And if i had the other handling options also how would their presence have added even more security and in what form?

GFL --> My guess is no. They stiffen the shocks or change the throttle response but dont really modify the limits. on on rough surfaces stiffer suspension may be bad. Long discussion on car dynamics and how mis-uinderstood they are in general.

if there's a corner on your daily drive home that you now know well enough to take at 100

GFL --> There isn;t.

what would happen for the sake of argument if you were to increase that speed by one mile an hour each week? and when whatever it was that did happen eventually happened would it be bells and whistles all going off and saying naughty boy? or would you be in the adjacent field before they could talk to you? which would come first?

GFL --> On track that is exactly how one does it. Sneak up 1mph or so at a time, recognizing that watching the speedometer takes your mind and eyes from the road you hope to stay on. Typically, you would first get a PSM indication, and be saved. You might also begin to get tire howl, or more of it. You might get a small slide ( be prepared to catch it - and DONT try to catch it by pulling the car back - that will cause the very spin you wish to avoid - let it run little wide). If you are moving truly by 1 mph, under the SAME conditions same place on the road, same temp, same humidity (hopefully: none) the change will be small enough to run wide and remain on the road. This is your warning to slow down.

That said, doing this on public roads with curbs, fall-offs, people, dogs, deer, etc is not a good idea.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com