tmpusfugit

With 2 cars off the road at the same exit at nearly the same time I would suspect a truck lost a bit of diesel fuel as it exited. I looped my 944 one day up in Dallas that way...like driving on ice. Also, "old" tires tend to harden substantially as they age. Some place or another I remember seeing a study that suggests that a tire progressing from new to old will lose more than 1/2 it's traction ability as its hardness increases. Sort of explains why on old tires one of my cars would break it's tires lose in 4 gears, and after putting on new tires it was difficult to spin them in first.....and 2nd, 3rd, 4th, no wheel spin....

Good to hear you hit nothing and came out of it OK

Leon Speed

So... what is taught in track school? Don't yank and lift, or yank but don't lift, or lift but don't yank - obviously yanking is always bad but let's say in an emergency you had to, let's say you're already at speed in a corner or just before a corner.

depami

Glad you (and the car) are unharmed. It sound like a variety of issues may be involved.

But, I think I'll pass on a school that has so much focus on yanking and lifting.

brutus

You learn how the car handles at and beyond the limit. Mostly learn that smooth is fast and avoid doing ANYTHING abruptly to upset the car. Yanking on the wheel being one of the more common novice errors as they race to turn the corner too hard and too soon, early apex, and wonder why they ran out of track on the exit.
With a 928 you learn how much better the car is than the driver !

Temekun

Driver error can make this happen. Too late on turn in, rear right rear hit wet grass, got helium footed and over corrected, too. Hilarity ensued. I learned a lot that day.

928 at last

Also depends on road conditions.......The driver error theory may be correct, but just for the sake of curiosity, I'd go back and in a straight line, brake hard. See what happens. We had an intersection around here that was like glass. (Now thankfully repaired) that I experienced gross understeer on a few times. Not sure what "polished" the pavement like that but it was interesting the first time. And that happened with fresh summer performance tires too. Might be a case where it was some of both at work.

Temekun

Sorry double the pictures, follow the lines...

https://rennlist.com/forums/members/...t-dsc05299.jpg

Temekun

I'll get this picture right this time.

928 at last

The key concept is to maintain the contact patch. If you're already at or near the limits on the tires, a sudden input, directional or acceleration/deceleration will mutliply the forces on that little bit of rubber by a huge amount. Tires lose contact, you lose control. On track, you want to brake as late as possible, and accelerate out as early as possible while maintaining contact with the road surface. The average driver, at speed in a corner is going to be in the rubarb if the patch is disrupted. If you're going into the corner, brake heavily, smoothly initiate the turn while releasing the brakes, and pray.
Smooth input at all times.

928 at last

As illustrated above. Where the pretty patterns in the grass begin, is where Temekun's contact patch stopped......

jcorenman

Mark, really glad to hear that you are OK.

I'm no expert (Jeff/Speedtoys is, however) but it's all about managing traction effectively. Different programs teach it differently, but all start with the basics: Four contact patches which can change the direction of their respective corner of the car, with a force that depends on how much weight is on that corner. You've got a throttle, brakes, and a steering wheel as tools to work with. How you use those tools is what driver's ed is all about.

Sudden steering (the "yank") shifts weight to the outside, while slowing shifts weight to the front. The outside-front wheel has great traction for changing the direction of that corner, while the inside-rear gets momentarily very light and has little traction, so the tail starts to slide. What happens next depends on what you do: Everyone knows to counter-steer to get the front to stop rotating, but if you don't get some more weight on the rear wheels then they're going to continue to slide-- just in a different direction .

That last part is where folks get in trouble-- every intuition (and maybe the co-pilot) is screaming "slow down!" but that will only make it worse-- the faster you slow, the lighter the rear end will become and the less traction that will be available from the rear tires. You need to get some power back on to get some weight on the rear.

Unfortunately most folks don't go past high school driver-ed, which doesn't teach any of this stuff. Some of it can be book-learned, but to be useful it has to become instinct, and that takes practice. You need to "become one" with the car, to sense the four corners as extensions of yourself.

The Pacific Northwest PCA region does two kinds of driver ed: First is "driver skills", doing basic exercises (one car at a time, with instructors) on various courses: Handling, avoidance, skid-pad, slalom, etc., usually in the rain (they do this in Bremerton, at the old airport). And then "Driver Ed" which is at a racetrack. Things happen fast on a track, and if you don't have the basics figured out first then you can get into the weeds pretty quick.

The other option is a multi-day professional course, e.g. Bondurant, Skip Barber etc. Sue and I took Bondurant's 3-day course together, decades ago when they were at Sears Point, and they did a terrific job. By getting totally immersed for three days you really "get it", and it begins to become second-nature.

Tom. M

I've done the pacnw region drivers skill day...it's an absolute blast...but the funniest/funnest part is when you get an instructor that only knows 911 handling dynamics..and tells you on the skidpad to speed up....and then abruptly let off the gas.....(he is fully expecting the car to swap ends)....and the 928...didn't LOL....so we speed up more.....and try again....nope..he is flabbergasted to say the least...finally I just give er the gas and drift around the skid pad.....and then turn in sharply to get the spin that he wants....
I think I made a convert to the well natured handling of the 928 that day .

BTW...I think the 928 could handle the transition you mentioned in the OP,..I'm guessing with the other car that spun...that there was something on the road.... (have you checked the bolts on the rear suspension??)

jcorenman

Yep, same thing-- except he started by looking for the handbrake
"Oh, you want the tail out? OK, I can do that". Fun stuff.

Don Carter

Mark,

Glad you didn't hit anything, very lucky of course in that crowded area. Also good to hear you have your car back on the road. Is there still construction around Taylor street, or is that all finished up?

No clue what caused your spinout, but I would think it would be a good idea to find a big open parking lot where you have lots of room and can get up to speed and play around with it. See if you can get it to do it again, and learn from it. Also a good check of the suspension makes sense. If you want to swap out wheels/tires to test that theory, let me know.

As for DE, I've learned recently that my daughter's best friend's father is a DE instructor at Texas World Speedway. He's a great guy and I imagine a very good instructor, so I'm wondering if we could put together a 928 group event at TWS, or at least join some other event as a group. I've never done DE but I'm ready to give it a try.

Speedtoys

Depends how aggressive you are with either..mostly it is thinking ahead of the problem and preparing for it.

Knowing that turning..turns the car, and LIFTING while yanking the wheel also rotates the car, I will tend to turn the WHEEL less and let the car rotate on it's own in a controlled..anticipated, slip.

Learning how weight Xfer rotates a car turns into a whole new set of tools to get a car to do something for you.


But..once you've lost the car..straighten the wheel..and go two feet in (clutch and brake). Then you can manage the spin without the really chaotic 'correction' spin. With the front wheels straight, you only spin 180d..and you slide straight. The good thing there, is you are predictable for the traffic around you. Those over-correction snaps back into traffic can hurt..just spin OFF the course/road and be your own accident.