Motor-Stadt Region

The Spin Cycle

by Len VanderJagt
LVJ911@worldnet.att.net

  Well, I asked for it, and I got it. Questions promoting discussion with regard to vehicle dynamics at high speed, or at least "too much" speed. In particular, our Esteemed President did indeed seize upon the opportunity to engage in consideration of what happens in the process of a spin. This is particularly relevant for Bruce, since based on his last two weekends at Mid-Ohio Sports Car Course, before and after the CART weekend, he has transitioned to Truly Fast, and the 911, if not the earth, is unquestionably moving under him in new ways.

  In order to go very quickly, it becomes necessary to "rotate" the car, having it move around its center of gravity even as it moves forward. When we learn to do this on purpose, it is "Yee Haw Time", but when we have it happen TO us, it is "Oh God Oh God Time". The vast majority of you haven't experienced the former condition, as it takes enormous practice, at speeds that are truly dangerous and irresponsible on public roads. (A way around this includes putting rock-hard overinflated tires on something like Tina the Wonder Truck and attempting to just turn at anything over 20 mph). The latter condition is something you can prepare for, for those times when you "run out of talent", or just flat over cook it.

  What are the "stages" of a spin? Well, like anything else, they are Confusion, Denial, Anger, Resignation, and Grief. In English, these stages are experienced as "Hey, what's going on, uh oh, uh, oh, this feels weird, feels bad, I hope it's not, it is, Oh God Oh God Oh God, AAAAAAAAAHHHHRRRGGGGHHH, Rats." Our goal, I think, is to minimize the necessity of a grieving process, yes?

  First, learn to identify and understand the data, to reduce confusion. Can you feel changes in the vibrations in the steering wheel? Can you sense that the angle of steering lock is no longer working as it was, somehow? Does your Posterior Organ feel "light" (followed by very tight)? Do you hear a change in the sound of the tires? These are all signals that Something is Changing. Yes, the Spin Cycle is beginning.

  What you are sensing tactually are changes in adhesion at the tire patches, followed by changes in slip angles. It is important to note that if your first clue is that you SEE the spin, through the windshield, it is way way too late to respond in any way other than Both Feet In. You will spin along a trajectory which roughly follows the path you were on (not your intended path, unfortunately), usually spinning to the inside of the turn (in the path of opposing traffic on that mountain 2-lane), largely because by the time you reacted the rear end of your (probably 911) has already gotten pretty much around on you. I will never forget the first time that happened to me, and you will have a similar indelible memory.

  Once you learn to pay serious attention to feedback through your palms, butt, and ears, you can learn to respond to exit the Spin Cycle before you are "hung out to dry." Possible options are straightforward, but not necessarily intuitive.

  If possible, steer in the direction the rear end is moving toward. You are now in effect having the front of the car race to stay ahead of the Big Bad Rear End, which has our old nemesis, Mo Mentum on its side. You also need to have room to go wide, because you are no longer trying to turn, you are trying not to spin first! A wall, a cliff, a tree, or some such to the outside of the turn, seriously compromise the palatability of this option.

  Notice carefully what NOT to do. Don't Lift! If you come out of the throttle, you transfer, or shift, weight/downforce to the front of the car, increasing front grip, decreasing rear grip, which by definition is already inadequate. End of story, you're toast.

  If the rear end only feels unstable, but isn't truly on it's way to the front, just keep steady and Don't Turn In More. Just keep your hands and feet as they are, while praying to Zufenhausen. "When in doubt, steady out", will keep you from creating the spin you fear but hasn't really happened yet, most of the time. Your Porsche is better than you are, let it do its job.

  If the rear end is truly letting go, but you have not insanely kamikazeed into the turn, gently squeeze in MORE throttle. This will transfer weight/downforce to the rear, increasing grip. Away you go, feeling like Mika Hakkinen. Please note. If you mash the gas pedal to the floor, and you have anything bigger back there than a 3.0 (or you have 8 cylinders up front, or 2 turbos, etc), you may well make things Very Bad by overwhelming the rear tires with both the existing side-slip and your self-inflicted wheel spin. Think Corvette driver. Ugly, isn't it?

  None of these solutions involve using the brakes. Here is the Devil's bargain. In order to avoid the spin, possibly, you don't slow down, definitely. If you lose this gambit, you may lose big. You will be going faster when you make the Big Stop. Pretty sobering, I hope, with regard to getting in over your head.

  Folks, this is why we offer PCA Driver's Education. You can learn car-control in a safe environment, and be prepared to 'save it' when you realize that it wasn't a good idea to stare too long at the CD player controls.

  Our Esteemed President has not forgotten my disclosures of actually letting go of the wheel on two occasions to regain control. This idea came from some Big Pro Road Racer some years ago, regarding street cars, noting that with their caster (centering action of the steering wheel), the front wheels at some point straighten out and you 'start over' with the steering of the car. Wacky as this sounds, it worked, at least in a Toyota Supra loaner car that 'belonged' to Turbozilla Denis Hall on the infield track at Michigan Speedway, and at least once in 'Ol Wayne hisself, in an autocross. My advice is don't try it. Better you should avoid such desperate straights, and try to steer properly. With the proper bottle of wine, however, I would be happy to discuss this type of maneuver in more detail.

  No one has offered an opinion on ABS-related aberrations, and I await your emails at LVJ911@worldnet.att.net.