TD in DC

At VIR with NNJR this past fall in the white run group, I had to use brand new street tires (SO3s) due to a fitment problem with some R-compounds a friend had loaned me.

The tires were super greasy, and I slid around all weekend with the tires howling. Fortunately, the sliding was very predictable so it wasn't too disturbing. The "limit" for me through the weekend became my tires more than the car or me.

One place where the tires were sliding and howling a bit was through the climbing esses, which is a place I had never experienced so much car movement before. I described this to a friend, Rob G. , and he took some video of my car going through the esses from the bridge. If you look closely, you can see the rear of my car start to slide out a little. In the car, the tires were really "talking" to me. Mine is the silver 996 Targa with the rear wing.

http://media.putfile.com/VIR-Todd

TD

P.S. The pass at the end looks even closer on video than it felt like in the car. Both me and the car in front of me got passing signals from two cars. We both took the passes and entered the esses offline. IIRC, he slowed a little more than I would have if I had been in front, and the Elise cuts in fairly closely at the end. No big deal while you are in the car, but it is strange to see it from the outside on video.

EDIT WITH A QUESTION:

This video also really shows how much tires can affect lap times. In the past, I have been on the throttle fairly hard all the way through the esses. In this clip, you can see that I back off a little right after the rear-end starts sliding, which allows the cars with r-compound tires to make a little space between us. My instincts told me to back off a little in light of the way I was sliding around, and I made it through the weekend without incident. I still think that is correct, but is there a chance that I would have experienced even less sliding if I had pulled my skirt down and gotten on the gas even harder (smoothly of course) so that I transfered even more weight to the back? I think the result of that would have been merely to make my tires slide even more, but performance driving is not always intuitive so I have an open mind.

James-man

Welcome to my world of heavy cars and street tires.

Screeching & howling, maybe even some sliding. No harm if you keep the rhythm of the "dance" going through the Esses right?

Like your videos - they are fun to watch.

TD in DC

Thanks! It was fun, although it would have been even more fun to mix it up better with the rest of the guys, who were all running R-compunds, particularly those who were driving pretty well.

Chris M.

Cool video, looks like a blast.

c

Larry Herman

Todd, unless you are getting power oversteer (and that usually only happens in really tight turns or with big hp), never ever lift when the rear starts sliding. It usually starts to slide because you are accelerating, and asking the rear to carve too tight a radius turn. That is why you have to unwind the wheel when the back of the car reaches it's limit. And you have to take a line that allows you to do this. Lifting places even less weight on the rear tires, and will give you less grip back there. Driving that way, they will only hook back up once you have slowed down a bit. Not the preferred way to exit a turn. Remember that is why you are learning on a low hp car, to learn how to control the back of the car with the steering wheel as you corner with your foot on the floor.

Eli K

Very nice Todd. Good driving. Even with the street tires you're moving!

TD in DC

Hey Larry,

Just to clarify, I wasn't lifting through the esses . . . at all. Rather, I was maintaining a modest amount of acceleration so that I could keep the weight slightly to the rear of the car. I know not to lift, thankfully.

In the past, I was on the throttle hard through the esses. My question really is whether I might have slid even less this time on slippery tires if I had driven the car harder when I started to hear the sliding. In other words, harder acceleration rather than modest acceleration. It is one thing not to lift, it is entirely another thing to become more aggressive after you feel and hear the car sliding.

In lower speed turns, I have really started to learn to use the throttle to steer the car. I haven't grown enough chest hair yet to apply those same lessons to high speed turns like the climbing esses. The light was starting to come on as I watched the video that my self-preservation instinct might have been compounding the problem rather than alleviating it. Is more traction through more aggressive driving possible?

TD

Larry Herman

Todd, I don't believe in "throttle steer" on the track unless you are driving a 600 hp car. That is an autocross tool on really tight turns, where you can adjust the line of the car through the turn by adding or removing throttle. On the track, I want to be floored through the turns. Yeah, you read it right....FLOORED. So there is no throttle to adjust. You turn in, pick a trajectory and STEER the back of the car through the turn. The tail is going to want to take an arc, based upon your speed and the amount of available grip, and your job is to use the steering wheel to keep the front of the car ahead of the back. That is the way I do it in most turns.

So how do I take the esses? When I get it right, I lift right before the 1st ess to make sure the nose turns in, and then floor it, and drive it up to the 3rd ess. I lift there, again to make sure the car turns in, floor it again and drive it right up until it is time to brake for South Bend. When you do it that way, it is really fast.

And when I get it wrong? If I realize that I am not quite where I want to be in the turn, i.e. going wide, I will sneak my foot off the floor just a little to gently reduce the acceleration. Hopefully that will allow me to hold the wheel a little and hold the arc a little tighter until the car gets back on line. If I feel that I have blown the entry, I will not get on the gas as hard until I have it collected and back online.

TD in DC

Understood. You and I have had this conversation before, and I believe you. What happens when you start having a tire issue? Does that mean that you adjust your entry speed (i.e., enter slower), and then continue to floor it through the climbing esses?

Also, I may have misused the term throttle steer. What I really mean is, in low speed turns, I have learned in the 944 to use braking to get the car rotating and then get on the throttle hard once I am pointed in the right direction to rocket out of the corner (well, rocket is probably not appropriate for the 944) I am using the same line I used before, but now I use braking to rotate the car as much or more than steering input, and I use the throttle to stop the rotation at the desired point. Not really sure how to describe that.

As always, thanks a million for the help.

38D

I've also gone into that first left flat out, then lifted a bit for the turn in to the right, then flat out again. Seemed about the same speed-wise as the method you describe.

Larry Herman

Exactly, I will slow my entry speed a little more so that I can still get on the power. Regardless of the grip of your tires, most times it is all about being on the gas as long as possible.

Dude, that is the essence of trailbraking. No need to describe it any other way. You are braking later, carrying more speed into the turn, and accelerating hard out of the turn. Sounds pretty fast to me.

My pleasure. All of your questions make me to re-think what I am doing, and come up with proper reasons for doing so. Maybe you are helping me to get faster too.

BrianKeithSmith

Man, I wish I had the nerve to go flat out through the esses. I'd like to say my car could do it, but I don't think I have it in me.

Brian

78SC

Looks good TD my only suggestion would be to use more of the curbs to straighten the esses out as much as possible. The fastest guys seemed to go over each curb and even kick up dirt from dropping the outside tire over the curb.

Capt. Carrera

Perhaps, but as you said yourself, it could have put you in a full spin. It all depends on what made the rear come loose to start with. The fact that you didn't induce a large dollop of trailing-throttle-over-steer tells me you didn’t pick the wrong solution.

I believe TD is taking about modulating the throttle through the corner, which is exactly what one should be doing. As for true "throttle steer", I use it at times, and my car has way less than 600hp. Like left-foot-braking, it's just another tool.

bobt993

Todd, I have a dvd of my car going up the essess (993) sent to me by a driver in a pretty modified vette during a DE event in March this year. It was my first session with the new car, tires, and setup. He had a good time chasing me, so it is pretty close action. I will try and send you a clip or if you want the entire dvd just add a destination. A really great guy from NC and he was kind enough to send it to me so I will pay it forward to others. Track was very slick (light rain) and cold (50deg). Next day proved better.