Friday, January 7, 2011

Track Day Driving Techniques

Stitching the Corners Together

If driving fast were a simple matter of braking, downshifting, turning in, hitting the apex and accelerating out as you released the wheel, then speeding down the straightaway until you got to the braking point of the next corner, racing and autocrossing would be a lot easier—and probably not nearly so much fun—as it is.

In fact, most race courses and nearly all autocross courses have only two or three places where you are simply driving straight down the course while accelerating and up-shifting. Instead, most corners come in groups. No sooner are you out of one corner than you have to prepare for the next one. In fact, in many situations you may find that you need to begin preparing for a corner before you’ve had the chance to complete the last turn.

It’s in these combinations of corners that less powerful cars can often overtake more powerful cars, and where the better drivers can improve on their lap times and overtake the less-skillful drivers. What’s necessary is to be able to think of the entire series of corners together. Your choice of entrance line into the first corner should be determined by where you want to be when you come out of the last corner, and each of the in-between transitions in speed and direction should be made as smoothly as possible.

Two-Corner Combinations

We can start with the most obvious situation first, where a right-hand corner is followed immediately by a left-hand corner, or where the opposite is true. To drive this two-corner sequence effectively, two principles need to be kept in mind. First, you should “use all the track” as your instructor no doubt will remind you. Second, you will need to make your weight transition—from leaning in one direction to leaing in the other direction—as smooth as possible.
When discussing how to go around a corner in the previous chapter, we stressed going to the very outside of the track before beginning the turn, and then touching the inside curb on the curve, and finally going to the very outside of the track on the exit. Generally, this principle will continue to be true on most right-left and left-right sequences.

Thinking in terms of the right-left sequence, the additional factor in this situation is that, as nearly as possible, the exit point for the first corner should be the entrance point for the second corner. Since you can maintain more speed on a larger-radius curve, you want to go out to the outside to begin the first corner, then go all the way across the track and stay on that side until you’re ready to make your turn-in into the second corner.

If you just drive down the center of the track around both corners, both turns will have to be sharper. If you don’t take advantage of all the track on the entry to your first corner, you will be entering more slowly than necessary into the second corner.

Even worse, if you start to make your turn into the second corner too soon, you’ll find that you’re carrying too much speed to make the corner cleanly. Instead of going around cleanly and smoothly, you’ll find yourself scrubbing off speed, or even going off the track on the outside, as you attempt to get around the second corner.

In the situation where two right hand corners, or two left-hand corners, are taken in a row, the same rules apply. As usual, you go as wide as possible before making your turn-in, generally waiting until you can see your apex before turning. Then you complete the turn by going as wide to the outside as possible and stay on the outside of the track until you are ready to make your turn-in towards the second apex.

The second factor in a combination turn is the weight balance of the car. Essentially, the principle here is that you want the car to be upright and moving in a straight line after completing the first turn and before beginning the second turn.

In the right-left and left-right sequence, the car must first tilt in one direction and then tilt in the opposite direction. If you attempt to begin the second turn before the car has finished its first turn, and before the car is again balanced at the center, it can be very easy to upset the car’s equilibrium, causing it to push or spin.

Instead, try to be conscious of how the car’s center of gravity first moves to the outside of the car as you begin the turn, then moves back over the center of the car as you unwind the steering wheel after passing the apex of the turn.
As soon as the car’s center of gravity is back over the wheels you can begin making your second turn. Done properly, the movement of the center of gravity will be smooth, and the momentum of the shift in balance will simply continue across the car until the car is leaning in the opposite direction going into the second corner.

In the instance where two turns in the same direction follow one another, you still need to be aware of how the car’s center of gravity is shifting. The car will progressively tilt away from the turn as you turn the wheel into the turn. Then as you gradually unwind the steering wheel coming out of the turn, the car will come back into balance, just as it did on the left-right and right-left sequence.

However, in this case, you need to avoid allowing the momentum of the weight transfer to cause the car to tilt too far in the opposite direction before you begin your second turn. By carefully controlling your acceleration out of the turn and the speed with which you allow the steering wheel to unwind you can begin the second turn just at the instant that the car is balanced, thus avoiding the problem of understeering and losing speed by plowing into the second curve.

..stay tuned for more..

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