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Pls Help Diagnose a Spin?

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Old 08-28-2010, 12:20 AM
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CRex
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Default Pls Help Diagnose a Spin?

Guys I had a rather weird spin at a local track last weekend that was too close for comfort. Track conditions were hot+dry (95 degs ambient) and coming out of a turn my car snap-oversteered after I'd gave it partial throttle past apex. (normally this would've been a full-throttle exit for most drivers)

My countersteering didn't do anything to catch the slide once it started. Can somebody please take a look and help educate a blue group driver? It's my first time running a new setup (Toyo 888s) and I'm not sure if its the hardware or the nut behind the wheel

Some have commented that I should've given it throttle to "catch" the slide. But I don't think I had the ***** to do that with the nose pointed at the inside concrete wall

FWIW, T2 on this track is not considered a "danger" spot but weirdly I was one of three spins there that day. The first spin claimed a BRAND NEW 458 (1st RHD car in HK) and you can see the tire tracks it left behind in the last 10 secs of the vid.

Any pointers would go a long way towards educating a novice driver. Thanks in advance!

p.s. the embedded video's a tad too small for the subtitles... helps to pop the video open in a new window and view it in 720p HD.


UPDATE: FULL SPEED VIDEO ADDED ON PAGE 2

http://www.youtube.com/watch?v=DpqwJyqSJvA&hd=1

Last edited by CRex; 08-28-2010 at 12:11 PM.
Old 08-28-2010, 12:26 AM
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mooty
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never been to that track
from your str angle appears you held the car too long (didn't unwind), can't tell actual speed as video is at 1/3 real time, so rear end come around. at that time you may have unintentionally decreased throttle. just my two cents
Old 08-28-2010, 12:42 AM
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CRex
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Originally Posted by mooty
never been to that track
from your str angle appears you held the car too long (didn't unwind), can't tell actual speed as video is at 1/3 real time, so rear end come around. at that time you may have unintentionally decreased throttle. just my two cents
Thanks mooty--I was going at about 59mph / 94kph when the slide started (speedo in lower right hand corner). Accelerometer read 1.5g which puts me at about the limit of the 888s, so I gather from others with more time on these tires.

Agree with your observation about the unwind. Having failed that in the first place, what's the right throttle response when the tail starts coming undone?
Old 08-28-2010, 12:45 AM
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Jim Michaels
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Watching the video I was also surprised when the rear started to slide. Maybe you gave it more throttle than it sounds like on the video (and more than you thought). If you were running street tires previously, R888s do break away more suddenly. If that was the first time out on new tires, perhaps the slippery mold release agent hadn't been fully scrubbed off yet.

I know it's counter-intuitive to continue with the throttle when the rear is sliding out, but if you lifted suddenly, that transitioned weight from the rear toward the front, which further reduced rear grip.
Old 08-28-2010, 12:45 AM
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Andrew D.
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Mooty is right on. Oversteer was induced due to not unwinding enough on the exit. Throttle lift made it worse. Watch the tach on track-out.
Old 08-28-2010, 12:48 AM
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What appears to me is, as Mooty mentioned, late in unwinding, if the data is synched properly with video, you lifted off the throttle; the combination is sure to spin IMHO.
Old 08-28-2010, 12:57 AM
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CRex
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Thanks guys--looks like I have some work to do with the throttle.

Now when you all refer to "lifting" the throttle, I was actually on the throttle until the slide started and I began counter-steering (0:13-0:16 in the vid). Should I have kept the throttle on through the counter-steer?
Old 08-28-2010, 08:24 AM
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bobt993
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Crex

I don't know the track, but the line seems wrong. Your running out of track onto a straight way too early. It looks like the car is having a hard time getting to the apex in T2 and starting to push before the apex. #1 adjust your entry into T1 so you can get proper track out exit in T2 and unwind the wheel with power. Your hands need to be more on the wheel, fingers on the edges are not going to give quick inputs or feel the car enough. That correction needed to be much faster, but the mistake started in T1 entry. I think your reaction to less throttle and holding wheel angle was normal when your view forward is a wall and not the turn exit. I always tell students to look up the track and if they see wall instead then they are not orientated correctly.
Old 08-28-2010, 08:36 AM
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Gofishracing
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It also looks like you were into ABS a bit which unsettled the car on corner entry then unwound / rewound wheel mid corner trying to hit second apex while still on the throttle which transferred weight combiined with a slow recovery. Classic. I like the right hand drive- Probalby one even set on wheel around that section is all you need. Work on your hand positioning on wheel.
Old 08-28-2010, 09:02 AM
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Matt Romanowski
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Originally Posted by CRex
Accelerometer read 1.5g which puts me at about the limit of the 888s, so I gather from others with more time on these tires.
This will get you in trouble. How many Gs the car can pull is dependant on track conditions, weather, pavement, track camber, car setup, etc. There is no way to say that a specific tire is always good for some numbers of G force.

There's a corner at NHMS that you can pull well over 1 G on street tires. Hoosiers can pull 3+.
Old 08-28-2010, 09:16 AM
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CRex
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Originally Posted by bobt993
Crex

I don't know the track, but the line seems wrong. Your running out of track onto a straight way too early. It looks like the car is having a hard time getting to the apex in T2 and starting to push before the apex. #1 adjust your entry into T1 so you can get proper track out exit in T2 and unwind the wheel with power. Your hands need to be more on the wheel, fingers on the edges are not going to give quick inputs or feel the car enough. That correction needed to be much faster, but the mistake started in T1 entry. I think your reaction to less throttle and holding wheel angle was normal when your view forward is a wall and not the turn exit. I always tell students to look up the track and if they see wall instead then they are not orientated correctly.
Much appreciate the pointer. FWIW T1 & T2 at this track is a compound corner and we're taught to early-apex T1 to setup for a smooth entry into T2. So Bob you're right on--the line was clearly off from the get-go (funny I was blind to it until you and Gofishracing mentioned).

Getting the line wrong in the T1 brought steering unwind-rewind in between T1 & T2 and that certainly didn't help with keeping the chasis in balance. Mistake begets mistakes!!

FWIW, here's a track map to illustrate what the turns ACTUALLY look like, courtesy of Wikipedia.

I guess as a matter of self-preservation, what should I have done to save the car once the slide started? I ended up with a thin strip of blue paint on the rear quarter panel and that's a stark reminder that had any of a hundred variables been different I would've come back on a tow truck...
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Old 08-28-2010, 09:57 AM
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Hmmm...

First of all, I don't like your handling of the wheel. Just having your finger tips on the wheel is not proper. Only having that small surface area for grip necessarily means you would have to apply a lot of pressure to your fingers to maintain control of the wheel. that, or you are only really gripping with your right hand, tugging the wheel down. You need a complete but relaxed palm grip on the wheel with both hands equally. You apply pressure with the palms of your hands at the knuckles to generate normal steering loads with your fingers wrapped with light grip around the wheel. When you use the entire area of your hand for surface grip, your mechanical grip can stay relaxed so that it can sense and react to minute changes in chassis balance and also feel subtle front tire activity. Simply using your finger tips will also not afford you the mechanical grip on the wheel necessary to make the violently quick corrections necessary, in this case back to the left, to catch rapid slides or step outs... or even this lazy slide.

Next; you are a victim of your tire timing, i.e. too early to go to R-tires. I'm not sure you have learned all there is to learn about what a car feels like when it is just beginning to step out. Even Toyo R tires are not nearly as forgiving as a street tire, nor as overtly communicative (and Triple 8s are far less so than RA1s). They grip well beyond a street tire, but then let go much quicker. You must be able to react on instinct and the feel of a tire starting to slide, not on the yaw angle of the car (which comes far later), and even though street tires have amazing grip these days, they will still teach you a lot more than Rs ever will. Street tires communicate by letting you feel them. Rs communicate with a slap upside da head!

Next, and in conjunction with the tires - "slow hands." This was a very lazy spin, and you did not react in time to nip it in the bud early when it would have taken just a flick to eliminate side load on the L/R tire. If you tune your butt to react when it senses loss of grip, you will only need a slight left/right jerk steer in that situation. If the car gets to actual yaw, where the chassis is not pointed in the direction that the mass of the car is headed, and you start to counter, you are at even money... IF you have the steering skills. You do not, or at least did not in this case.

I agree that you were guilty of being a bit clumsy with your braking. Unsettling the car and the driver at that point is not that helpful, especially given the previous point. Too much extraneous input to the chassis and brain muddles the mission.

Last (and this is what CAUSED the moment to occur); I agree that your line was a bit faulty. That really appears to be a corner with one smooth flowing line around it, the apexes being rather irrelevant in terms of changing the trajectory of the car. You arguably turned in a bit early and were headed in a bit early for the second apex area, but you then made a classic novice mistake of not trusting or holding your line, and steering away from your apex. This unfortunate bit of nervous over anticipation firstly removed the side load from your tires at the point where you needed it most (at the grip apex, not the physical one(s)). Then when you steered into the corner again, you reintroduced side load when you should have been preparing to unwind the wheel. I think you need to reorient yourself with that turn by going a bit deeper, more or less skipping the first apex, and then not steer as much to allow the chassis to set and rotate itself around to make use of the 2nd apex as your ONLY real apex in that turn. As you become more comfortable and familiar with it, you can then begin to be a bit more aggressive with it again. An advanced driver would likely take a very tight line there, covering as little physical distance as possible, and trail braking to achieve rotation in the early part of the turn, but you would need a ton of chassis grip, and driver talent (skill sets, feel & anticipation) to make that tight line work.

That's my $.02 worth, based on very little knowledge of your actual situation or the Zhuhai circuit. I applaud your open attitude, and hope this all helps you. Consider that spin your freebie. One cannot or should not expect too many Mulligans in this game.

Last edited by RedlineMan; 08-28-2010 at 10:24 AM.
Old 08-28-2010, 10:01 AM
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It's really impossible to tell anything from this slo mo video. Post a full speed version. The advice up to this point is highly speculative.
Old 08-28-2010, 10:03 AM
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obsessedone
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what should I have done to save the car once the slide started?

Countersteer while squeezing on a bit more throttle to shift weight to rear to help rear wheel traction, looking ahead down the track always helps and in spin it helps as "your hands follow your eyes" helping you countersteer.

That said, if it becomes clear your efforts to recover aren't working, "both feet in" immediately is usually the best action as with both feet in your car will tend to travel predictably in the direction of your momentum (generally towards trackout) avoiding a secondary snap or spin towards the inside of the track. By sliding predictably towards trackout you are less likely to hit obstacles at most tracks and it is easier for following cars to avoid you.

Also remember to monitor and adjust tire pressures as overinflated tires reduce adhesion - in the hot conditons you descibed tire pressures can easily rise above your desired hot temperatures - might have been a contributing factor.
Old 08-28-2010, 10:50 AM
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I would have been good to see it at regular speed followed by slow motion, but from what I could see... didn't unwind soon enough.


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