This is post #2 in a series of articles about some of the biggest lies in high performance driving. In this post, I’m going to address one of those things HPDE coaches say with a chuckle: “use the whole track, you paid for it”.
The whole track
What exactly do people/coaches mean when they say “use the whole track”? Certainly they don’t mean that you should zig-zag back and forth to make sure you tread all of it, but that’s the image in my mind when I hear it. Since I never say it, I’m going to suppose they mean to take an outside-inside-outside path through a corner. You know, set up on the outside, turn in and touch the apex, track out to the exit. That kind of path maximizes the radius through the corner and therefore maximizes your speed. That should minimize your lap times too, right? Not always.
Imagine you’re all alone on a 16 lane highway (8 each side) and you want to make a U-turn. Given that nobody else is around and you can take any path to make that turn, are you really going to set up on the outside, cross 8 lanes to hit the apex, and then cross another 8 lanes to track all the way to the exit? Legality aside, it’s actually not faster because you traverse way too much track. The racing line through a corner depends on the acceleration of the vehicle, the grip of the tires, the geometry of the corner, and the width of the road. When acceleration approaches grip, it’s better to drive the shortest path even in a 90 degree corner. At this point you should be saying “show me the data”. And I will, but in another post. For now, let me point out that in a 360 degree corner (a skid pad) the smallest radius is always the fastest way around. That’s because velocity increases with the square root of the corner radius but the circumference increases linearly.
Explore the space
I think “use the whole track” is actually a very advanced lesson, and not something you teach novices. In fact, I don’t want novices to use the whole track. I would prefer that they leave quite a bit of margin for error, especially on the exit. So I never say “use the whole track”. If you were my student, I would tell you to “explore the space“. By space I mean both the physical dimensions of the track and the limits of grip, but more grip than space. Feel what the car is telling you. Listen with both your hands and ears. Once you have the confidence to control a sliding car, then you can worry about minimizing your lap time by maximizing your speed through a corner. Until you can balance a car on the edge of traction, I don’t want you going anywhere near the edges. So drive harder closer to the middle of the track and get a feel for a car being driven aggressively. If you mess up, there’s plenty of space to recover.
So let’s say you have decent car control and you want to go faster. Now you’re ready for the real lesson in using the whole track. You need to use all of the grip through all of the corner. The line isn’t an arc through a corner. It’s also got dimensions of grip and yaw along its length. Maximum grip is at a slight slip angle. Meaning you have to be slightly sliding through the entire corner. If you’re not sliding on the way into the corner, you entered too slowly. If you’re not sliding on the way out of the corner, you were late to throttle. If you’re not making subtle steering corrections, you aren’t getting enough oversteer. If you’re making big steering corrections, your technique lacks precision. If you find yourself spinning, you didn’t open up the steering wheel before adding throttle. If you find yourself running out of track at the exit, you need a later apex or more rotation. If your tires screech and then go quiet, you used too much grip at once. This is a lot to digest. Ultimately, it’s not about the track, but rather your ability to maximize the grip of the car along its entire path through the corner. In most corners, that will see you taking an outside-inside-outside path, but the exact geometry of the car on that path must also take into account the angle of the car at all points along the path: it’s not exactly parallel to the path at all times. “Use the whole track” is a heck of a lot more complex than it first appears and sends the wrong message to the student. Here’s my alternative.
Use the whole car, you paid for it