Hitting Apexes…. Oct 2014

As I was sitting here thinking about what to write about, I started thinking about my DE Checklist and did I have everything set for our upcoming Watkins Glen II event on September 15-16. It has been 6 weeks since I have been on a race track so I am pretty stoked about this event. Following the Glen event is our NJMP Lightning DE on October 18-19 and then two weeks later we will be at VIR on October 31 – November 2. As soon as I get back, we go into planning mode for our 2015 season. First up is our Mid Winter – Intro to DE in January followed up by our High Performance Driving seminars for Drivers and Instructors (separate sessions). Well, if I cannot drive on a track in the winter, at least I can think about driving on a track.
Last month I covered the topic of passing which I hope you enjoyed. This month is about “Learning the Line”. Here goes (special thanks to the folks over at NASA, SCCA and BMW who made major contributions with the content of this article).
Learning the Line
The “line” is the path around the track, that when driven at the limit, will yield the fastest lap time.
For new drivers, the line through any particular corner is accomplished using a “connect the dots” approach. To get terminology cleared up first, every corner is made of three parts. We will call them the entry, the apex and the exit. The entry is where turning begins. The apex is the point where the car reaches the furthest point on the inside of the turn. The exit is where the car is driving straight again.
The objective in driving through a corner, or a series of corners, is to have the fastest possible speed at the exit of the corner, or the last corner of a series. It is not necessarily to have the fastest speed going into the corner, nor even the fastest speed in the middle of the corner. The last corner exit before a straight is the most important segment. The speed of the exit determines the speed during and at the end of the straight. If you can increase the average speed of an entire straight, that will have greater impact than a faster average over the shorter distance of the entry to the turn, or through the turn itself.
The path or “line” you drive through a corner will determine the exit speed. In general, the fastest line through a corner is the one that allows the greatest radius, or straightest path. As a car can go faster around a large corner than it can around a tight corner, the shortest path around a corner is rarely the fastest.
Going quickly requires that you learn the line and drive it consistently and precisely. One of the biggest stumbling blocks to learning the line is overdriving the car while trying to learn the line (Particularly at corner entry).
If you are going slower than the traction limits will allow, you can place the car exactly where you want to. If you are going too fast, the car will be controlling you, and you will be forced to follow the line established by the speed of the car.
Most of you have heard at one point or another the adage “slow in, fast out”. The most important goal of most corners is to carry as much speed as possible onto the straight following the corner. It has been said that the race winner is not the guy who goes fastest around the corners, but the guy who gets between the corners fastest.
The proper line can often be felt. Some things to look for:
At the “turn in” point, the car should be as close to the outside edge of the track as possible, this will allow the car to travel the arc of the greatest radius through the corner. At the “apex”, the car should be as close as possible to the inside edge of the track and at “corner exit” the car should be all of the way to the outside edge of the track again. Many turns have “berms” (usually a concrete curbing) at the apex and corner exit. More advanced drivers commonly drive on the berms to increase the radius of the turn by another few inches. I do not advocate that in a street car, but I ask my students to try to just “feel” the edge of the berm, to know they have used the whole width of the track. Note: It can be helpful in learning the line to look at where the rubber has been left on the berm by the other cars.
Tip: You will know when you are on the correct line when you turn in at corner entry and do not have to change the wheel position again until you begin to “unwind” (straighten) the wheel about 50-75% of the way through the corner. You must hit your apex and wind up at the outside edge of the track for this to be meaningful.
This is what you will want to feel: At corner entry the car should turn in easily. The car will lean on its suspension and “take a set”, when it does you should gently begin to apply a small amount of throttle (the car is more stable under throttle than if just rolling free). Gently increase the throttle, feeling how much the car can take, if the car begins to go wide (remember, you must hit your apex!) either stop increasing throttle application, or lift very gently. Lifting quickly will probably spin the car if you are anywhere near the limit, but lifting gently will just point the car into the apex. As you pass your apex point you should be able to gradually apply more throttle, as you do you will feel the car tell you it wants to go straighter (because you are going faster) and you will have to unwind the wheel. This unwinding should carry you all of the way out to the edge of the track at your corner exit point. If the entire corner felt smooth and felt like the car was developing a consistent “G” force from the beginning to the end of the corner, you probably nailed it. Remember, none of this means anything if you do not “connect the dots”!
Most drivers use visual reference points to establish where they apply their brakes, the turn in point, the apex and corner exit points. It is the easiest way to be consistent, particularly when learning a new track. Look for objects that will always be there and that will not move. Cones are a bad idea, a missing chunk of pavement is a good idea. When establishing a braking point, be conservative. First, because of “slow in, fast out” and secondly because as the day progresses you will probably be exiting the previous corner faster and therefore carrying more speed into the braking zone.
Tip: While learning the line, if you find yourself running out of pavement at corner exit, move your turn in point closer to the turn (effectively creating a later apex). If you have pavement left over at corner exit, move it back. You must hit your apex for this to work! By delaying the turn-in point and beginning the turn with a slightly sharper bend, the car can be aimed to apex later than the geometric apex point. This straightens out the second part of the turn, allowing the driver to apply the accelerator earlier. The car will have to slow down a little more at the turn in phase, but exit speed will be higher. That exit speed gives the driver much more speed on the straight which will result in lower lap times overall.
This approach works for corners which require hard acceleration cornering out of them, which will be most of them. However, there are many types of corners, and combinations of corners which require some analysis to understand the best approach.
Tip: Next time you are out there on track, pick one corner that you want to master and apply some of these principles and practice until you get it right. Then move on to the next corner or two that you want to improve. After a number of sessions, you should be able to at least visualize perfect corners and then continue to practice and challenge yourself to achieve that perfect lap!!
See you out there soon and please keep the shiny side up.
Tom