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Data analysis on this mistake? Hit the wall at Watkins
Driving a stock NA Miata on street tires trying to gain some ground on a friend who just got an NB. Had a little red mist and did not make small adjustments to my driving. Added too much sauce going into the bus stop (10mph), started fishtailing at the exit, spun and hit the outside tire wall. I'm having a hard time piecing together what exactly happened. I remember going towards the 3rd set of curbs on the inside and the car sliding more than usual. Then I remember the car breaking to the right and thought it was going to spin. At this point I remember my foot over the brake pedal (I may or may not have pressed it) and the car changed directions to the left, then back to the right and that's when I put both feet in and slid backwards into the wall.
Looking at the data I think I panicked when the car was sliding a little bit and I lifted. If you lift in a slide I'm assuming that can initiate fishtailing? And then I exacerbated it by possibly hitting the brake? I normally slide a lot in here so I'm not sure what was different this time around to cause my lizard brain to panic.
Blue line is speed, green is lateral accel (left/right), yellow is longitudinal accel (forward/backward), purple is gsum. The washed out colors are from a previous lap for comparison. https://www.youtube.com/shorts/D8CzXu5Mzhc
Tough to make any constructive comments on your data without video. That third curb eats tires and sometimes cars but maybe you were already in trouble before that from your description.
Sorry that happened to you and glad you are ok. That's obviously the most important thing.
As for the hit, Two Words:
Too much of the 3rd curbing.
That 3rd curbing (2nd one on the left) has thrown more cars into the wall than I care to remember. I have my students just "clip" that 3rd curbing for just that reason.
I wish I had video. I had the gopro in the car, but just didnt turn it on. Would have been very helpful in this scenario. I'm very grateful for tire walls. Hitting a tire wall at 35mph felt hard, I can't even imagine what that would have been like if I hit the armco.
I wish I had video. I had the gopro in the car, but just didnt turn it on. Would have been very helpful in this scenario. I'm very grateful for tire walls. Hitting a tire wall at 35mph felt hard, I can't even imagine what that would have been like if I hit the armco.
My one impact (knock wood) at The Glen a few years ago was into the Armco between 7 and 8.
Control Arm snapped (or so we think), and the car made a left turn smack into the wall.
No time to react.
It felt just about how you would expect it to feel. Not Good!!
Would have much preferred a tire wall. (Obviously would have preferred NO wall at all, but if I had to choose.......)
If you take a lot of the third curb, and your car is pointed straight, the car normally handles it (some more than others). If you take a lot of that curb, and also have the wheel turned, the back end can step out on you pretty easily. That outside wall is hungry and has eaten a lot of cars.
The bus stop can be tricky - you alter something too much, such as your angle coming in or your speed, and if you don't modify what you are doing to account for that change, bad things can happen. As Frank said, its hard to tell without video.
If you take a lot of the third curb, and your car is pointed straight, the car normally handles it (some more than others). If you take a lot of that curb, and also have the wheel turned, the back end can step out on you pretty easily. That outside wall is hungry and has eaten a lot of cars.
The bus stop can be tricky - you alter something too much, such as your angle coming in or your speed, and if you don't modify what you are doing to account for that change, bad things can happen. As Frank said, its hard to tell without video.
IIRC from my last track walk there, there is one turtle on that 3rd curbing that is higher than the ones around it and that's what can throw a car into that exit wall if your wheel is even remotely turned. Caveat Emptor.....
IIRC from my last track walk there, there is one turtle on that 3rd curbing that is higher than the ones around it and that's what can throw a car into that exit wall if your wheel is even remotely turned. Caveat Emptor.....
I will take pictures of it this weekend at the track walk with GVCBMW.
It isn't much higher, but it is higher than the ones aorund it. Nasty little surprise waiting for folks who like that 3rd curbing and don't know about that turtle.
If you take a lot of the third curb, and your car is pointed straight, the car normally handles it (some more than others). If you take a lot of that curb, and also have the wheel turned, the back end can step out on you pretty easily. That outside wall is hungry and has eaten a lot of cars.
Looking at the GPS data it looks like I completely missed the 3rd curb, but did hit the 4th curb. Maybe slid onto the 4th curb and it upset the car? This is the stock suspension so it's really soft, I think they're 154/97lbs springs. Maybe they were loaded and hit the bump stops? I need to get a camera that continuously runs so I can't forget to turn it on.
It sounds like the car initiated a slide at least in part due to excessive speed, you may have lifted which would certainly have further unsettled the car. That situation alone could bring the rear around. Hitting aggressive curbing while in that state adds to the challenge.
It’s a little hard to tell, but there is a point right at peak lateral G where all of a sudden you start to get lots of longitudinal G. That tells me you hit the brake. The overhead view is not high enough res to say exactly where this happens, but it’s definitely near the 3rd rumble.
IIRC from my last track walk there, there is one turtle on that 3rd curbing that is higher than the ones around it and that's what can throw a car into that exit wall if your wheel is even remotely turned. Caveat Emptor.....
Not a function of steering input so much as throttle position: Drop throttle at or before the third curb and you’re done.
__________________ -Peter Krause www.peterkrause.net www.gofasternow.com
"Combining the Art and Science of Driving Fast!"
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It sounds like the car initiated a slide at least in part due to excessive speed, you may have lifted which would certainly have further unsettled the car. That situation alone could bring the rear around. Hitting aggressive curbing while in that state adds to the challenge.
Looking at the GPS data it looks like I completely missed the 3rd curb, but did hit the 4th curb. Maybe slid onto the 4th curb and it upset the car? This is the stock suspension so it's really soft, I think they're 154/97lbs springs. Maybe they were loaded and hit the bump stops? I need to get a camera that continuously runs so I can't forget to turn it on.
I would NOT count on logger GPS as absolute lateral positioning on any sort of map overlay, only RELATIVE position to another lap in the same session, on the same day. THIS is why video is key.
08-02-2023, 01:10 PM
Data analysis on this mistake? Hit the wall at Watkins
