Spun out at 95 mph - experience and analysis

[rnr]

I originally posted this on my blog - thought other etalkers might be interested in the account.

<a href="http://www.flickr.com/photos/rnair/238240632/" title="Photo Sharing"><img src="http://farm1.static.flickr.com/93/238240632_6b88256093.jpg" width="500" height="336" alt="Reno-Fernley course map" /></a>

I was at the <a href="http://www.elisetalk.com/forums/showthread.php?t=39375">NCRC trackday</a> at <a href="http://www.reno-fernleyraceway.com/">Reno-Fernley Raceway</a> last weekend when I got some first hand experience of what happens in a high speed spin. I was coming down the front straight at well over 100 mph and slowed slightly to take the esses that make up turn 1. Now on the track map they may look like fairly severe turns but in actual fact you just lift a little bit to settle the car at the end of the straight before flooring it though S bends. On this particular lap I came in a little hotter than on my previous runs and just after i made it though turn 1A the back end came around and I flew off the track at 95 mph.

People have asked me if my life flashed before my eyes but in reality the only thought that went through my head was "Please don't flip!" :-). The car was surrounded by a massive dust cloud which meant that I had zero visibility - I had the sensation of spinning and slowing down but had no clue as to which direction I was heading. As is standard practice during a spin I "put both feet in" (hit the clutch and brake) to ensure that the car has a predictable trajectory so that other drivers can avoid it. It probably took about 30 sec to a minute for the dust to settle but it felt like an eternity as I had no idea where on track I was or what the condition of the car was. Once the dust settled I found that I was in the sand/gravel trap about 50-60 feet from the left edge of the track and having done at least one 360, pointing in the correct direction. I started up the engine but since I couldn't actually see much of the road in front of me I backed the car up about 10 feet. Moving the car turned out to be an excellent idea because the dried grass under the engine bay had caught fire and when I moved I could see that the spot I had stopped in was actually burning (maybe 4-6 inches on flame). I then waited for a couple of the cars to pass before slowly driving through the gravel trap and rejoining the circuit. The car initially felt fine but as soon as I took a right turn I found that the steering was pulling to the left. While I initially feared suspension damage, by the time I got to the pits I was pretty sure that it was a flat in my left front tyre.

Examining the wheel in the pits showed that the flat was due to the tyre popping off its bead rather than an actual puncture. I borrowed a jack and pulled off the tyre before inflating it and reseating the bead. Luckily the wheel had no damage and the tyre held air with no leaks. I also checked for suspension damage but thankfully everything was solid. Now that the my greatest fear was passed, I examined the rest of the car for damage and amazingly the only other issues were a broken mirror on the drivers side and some minor paint chipping on the drivers door. The car itself was absolutely filthy with a thick layer of dust coating every square inch of the interior and exterior. I knew that going into the gravel trap would be dusty but never expected it to be this bad - my passenger commented that it felt like a dump truck had poured a load of dirt into the cabin. I drove into local car wash during the lunch break and washed the exterior of the car before spending a small fortune on vacuuming the dirt out of the interior. In about 2 hours time the car was most back to normal and looked like merely a dirty car rather an absolute write-off.

<a href="http://www.flickr.com/photos/rnair/495654176/" title="Photo Sharing"><img src="http://farm1.static.flickr.com/231/495654176_55daec99a6.jpg" width="500" height="375" alt="12052007591" /></a>

<a href="http://www.flickr.com/photos/rnair/495108121/" title="Photo Sharing"><img src="http://farm1.static.flickr.com/231/495108121_fea8489229.jpg" width="500" height="375" alt="Never lift!!!" /></a>

<a href="http://www.flickr.com/photos/rnair/495654748/" title="Photo Sharing"><img src="http://farm1.static.flickr.com/210/495654748_9385e382e4.jpg" width="500" height="375" alt="Result of the spin" /></a>

<strong>Post Mortem</strong>
Since this was my first track day with a <a href="http://www.race-technology.com/description_8_956.html">DL1 data logger</a>, I actually had detailed logs to help me diagnose what exactly went wrong in the corner. The first diagram shows the line I took through turn 1 while the second is a graph showing the speed and longitudinal G force plotted against distance. The red line is the lap I went off on and the black line is data from my previous flying lap. The first thing I noticed that my speed down the front straight was significantly higher than on that lap (114 mph Vs 107 mph). This meant that when I lifted to set the car up for turn 1 it took longer to get to the right speed and I ended up going into the corner a bit too wide (figure 1). As a result of this the car got a little loose through the turn and I instinctively lifted of the throttle just a tiny bit (figure 2). This created a classic case of <a href="http://en.wikipedia.org/wiki/Lift_off_oversteer">lift-off oversteer</a> where the weight transfered to the front wheels causing the rear to lose traction and come around. I have experimented with lift-off oversteer before and even use it at autocross to rotate the car but this was the first (and hopefully the last) time this has happened to me at such a high speed. It was a pretty scary experience and happened so fast that I had absolutely no chance of catching it - all I could do was hold on and hope for the best.

<a href="http://www.flickr.com/photos/rnair/503028955/" title="Photo Sharing"><img src="http://farm1.static.flickr.com/221/503028955_39d7bdc11c.jpg" width="406" height="500" alt="dl1 map trace" /></a>

<a href="http://www.flickr.com/photos/rnair/503029799/" title="Photo Sharing"><img src="http://farm1.static.flickr.com/209/503029799_d864204a1f.jpg" width="500" height="229" alt="dl1 xy" /></a>

In the end I was extremely lucky to walk away from a near triple digit spin with nothing more than a broken side mirror and a very dirty car. Having the DL1 was extremely useful in diagnosing the issue (especially since I don't recall lifting but the data doesn't lie) and gave me more confidence about going back onto the track. The next day I was back on the track and while I was initially a bit gun shy of turn 1, by the end of the day I was taking it at regular speed. All in all it was a very educational experience and reinforced the need to follow the mid-engine car drivers mantra - "Don't lift" :-).

[Jones-in']

Excellent post. Great data. Heaps of dirt inside your car!

On my first track day at Street o' Willow I lifted and spun off the track. Not doing anything close to 100 -- maybe 60 or 70. Very slo-mo experience. Lots of dirt and a red face. Otherwise car unharmed. I'm a track greenhorn, and the urge to lift is a tough one for me to break.

[gameson]

good thing you are OK!! that's one of the reason why I never track with top off, first is the safety issue, second is the dirt

[karlooz]

that is exactly where i spun when i was there a couple of years ago. same circumstances too but spun out on the pavement and never went off track. i lifted at 1A and ended between 1C and 2.

great data.

[pip]

Thanks ! Had to chuckle at all the dirt--glad you are OK!

[25psi_Elise_Killer]

I feel your pain man. Here's a pic of me spinning the car at around 110MPH on turn 1 of Streets of Willow. I did the same mistake of you of lift-oversteer at a high rate of speed. For those of you familiar with SOW, notice how far my car is from where turn 1 begins after the front straight. And yes the only thing that came to my mind as i slid into the dirt was "don't flip, don't flip, don't flip)

[codymac]

Excellent info, and even better that you just got the DL1! Thanks for sharing.

You're not alone. Back in January, I had a high speed spin, just over 180 degrees, in a downhill off-camber turn at our local track. I was feeling good all day, pushing my speed up higher and higher. On corner exit, things went sideways, the back came around and put me off the inside of the track, backwards, and hauling ass. Aside from the infield being very bumpy, it was a typical, calm spin. (For the locals, it was in Ricochet - running CCW, and I was boogeying.)

My only significant damage was several chips in the section behind the driver's front wheel - the rear tires must have found every rock in the grassy infield.


What I get for being cocky and listening to The Crystal Method while I drive.

I used to use a little lift-off to get the car to rotate in a tight chicane but have found, as I've gotten faster, that at the limits of traction, it's much more rewarding to give the throttle a little nudge to get the back to come around.


One of the reasons I love track driving so much: there's *always* something to learn. I'm so much better than I was and I've still got so far to go.

[MitchT]

After having tracked the elise in several different configuration

Standard suspension

Standard Lowered

Standard Lowered with 048, with dot 200 tread wear tires, and R- counpunds

Nitrons-lowered, aligned, courner balanced with r -coumpounds wider fr/rear.

Alot of the spins and offs are on based suspension cars.

Alot are with the ado7s being driven at track speeds.

The base suspension does not transistion that well. The car rolls and can snap around easier.

The observation: as your speeds and track experience increase the cars track preparation and your skill need to be insink. Do not expect based suspension to be race suspension, do not think that ado7s are race tires.

I have spun at double digits speed too, due to driver error, asking the car to do what it could not due 100% brake and 100% turn,but I find making the car more predictable ,stable and sticky ( tires ) is very important in running consistent and faster laps.

[NMRJock]

I had a very similar spin at a very similar speed. I ended up going backwards along the track for a looooong ways, then backwards up an embankment to about six inches from some armco. My passenger and I both described it the same way. Just sitting there waiting for the 'crunch.' I'm very lucky it never came.

[TOPGUN750]

Glad you are ok...thanks for the interesting and informative information. It is great that your track has runoff in instances where one spins.

[neckstrap]

rnr,

Excellent thread and information. It's great that you found the limits at the track and not the street.

Paul

[jlucas]

Makes you wonder how many times the data would have told a different tale than the driver. Sorry for you spin but at least you have data to know why.

[rnr]

Originally Posted by MitchT

Alot of the spins and offs are on based suspension cars.

Alot are with the ado7s being driven at track speeds.

The base suspension does not transistion that well. The car rolls and can snap around easier.

The observation: as your speeds and track experience increase the cars track preparation and your skill need to be insink. Do not expect based suspension to be race suspension, do not think that ado7s are race tires.

I have spun at double digits speed too, due to driver error, asking the car to do what it could not due 100% brake and 100% turn,but I find making the car more predictable ,stable and sticky ( tires ) is very important in running consistent and faster laps.

That is an interesting observation. My plan is to get to a consistent plateau of laptimes before actually changing anything about the setup. One of the worries I have about upgrading early is that it will mask deficiencies in my technique and when they eventually bite me I will be going at even higher speeds.

Any thoughts people?

[rnr]

Originally Posted by jlucas

Makes you wonder how many times the data would have told a different tale than the driver. Sorry for you spin but at least you have data to know why.

+1

I had absolutely no recollection of lifting and the DL1 was a great tool to analyse the spin and rebuild confidence. I highly recommend it to anyone who tracks and doesn't have one already.

[MitchT]

I do agree that your skills have to be there before you do mod or upgrade the car, but as you said 114 mph thur the twisties does sound like some slow poking speeds.

My point is that a street car is a street car and a track car gets a little more purpose built especially when speeds increases.

[JonOrangeElise]

I'm just glad this happened at R-F and not Laguna or Sears.

[carlover]

Thanks for taking the time to make this a great post.

[JMA]

I had a similar experience at Willow Springs (main course). My first race, coming down the hill in a left hander, doing about 100: "too fast, back off". What a mistake! Did a 360 in the dirt, thinking all the time, "please don't roll over". Ever since then I kept my foot all the way down in that turn, and never had a problem. More power on the rear wheels means more patch on the road, more grip. Let up, less patch on the rears, less grip, and off you go. I knew exactly what I did wrong that time, but am still trying to figure out some other spins (one was cold tires, I think). Car was a Lotus 51, Formula Ford.

[R'elise Me]

When I spin it's invariably due to "lift off" and/or cold tires. The Elise is so much more rewarding if you bleed a little more speed off before the turn and power through them, IMO. It makes more speed on turn exit which is really mportant considering our low torque / slow acceleration compared to the big engine cars that regularly trample us between turns.

[Steve W]

Particularly with the stock Elise, you almost can't go wrong with being pretty hard on the throttle in a fast corner. The car just doesn't have the power to power oversteer in the fast corners unless you totally bury the throttle.

One of the tricks I've seen from the really good drivers (particularly Craig Stanton) is never to be static with car inputs, Never hold the wheel in just 1 position, never hold the throttle in just one position. By dithering the controls about the edge of grip he gets a better feel for where the edge is, and when grip starts to go he's already moving the control in the right direction to get it back.

With a good driver it clearly works, because he drives a lot of very different cars, he learns the limits of any particular one very quickly. With us mortals I'm not so sure.