Monday, May 26, 2008

AutoX Course Description

Since I've mentioned the SCCA, Washington Region's Autocross School a couple of times, I thought some of you might be interested in reading in more detail about the course used to teach autocross skills at this school. By "some" I mean just 2 or 3 of you, but since we only have 6 or 7 regular readers, 2 or 3 represents a pretty significant fraction of our readership. This course is a little bit shorter than the typical autoX course---it takes me around 36 seconds, while most courses are designed to take 45 to 60 seconds---but it includes all the standard elements.
  1. The first element is a short, gentle S-curve to the left then right. It's only purpose is to make entry into the following element more difficult, and to give you a place to shift into second gear. You won't need your clutch or gear-shift after this. The first set of timing lights, the ones that start the clock, are located in the left-hander.
  2. Next is a long slalom of, I think, 5 cones. The goal here is to "backside" each cone, meaning to pass each cone while heading not parallel to the line of cones, but rather while heading in, toward that line. Doing this keeps you "ahead" of the slalom. (This notation makes a lot more sense if you have actually done this kind of thing.) Because of the orientation of the last cone and the following element---a left-hander---the last cone doesn't really matter, and I usually have my foot to the floor for the last 2 cones. Thus, by the time I brake for the next turn, Mia's tachometer needle is bouncing off the rev limiter. Well, I assume it's bouncing off, since I can hear the rev limiter pulling fuel flow; I don't actually know what any of the gauges are doing, since there's no time to look inside the cockpit.
  3. The third element is a left-hand sweeper through about 210 degrees. The turn takes you mostly up-hill and is on-camber. The only cone in the whole sweeper that matters it the last inside cone. You want to do whatever you need to in order to arrive at the cone positioned very close to it, but also pointed at the center of the next element. If, instead, you cleave close to the first cone, you will artificially tighten the radius of the turn, reducing your speed through the turn. This sweeper is my favorite element in the course, because I do a lot of the steering with the throttle. I look at that last cone from the very beginning, set the steering wheel at an almost fixed angle, and use the gas pedal to control the line the car takes. I can usually establish a nice, controlled throttle-induced oversteer almost all the way around the turn. I find it useful to lift off the gas as I approach the final cone, transfering weight to the front tires, and allowing the rear wheels to slip out, thus rotating the car and pointing it at the next element as I pass the final cone.
  4. The next element is called a "straight" in autocross, but, since it's only about 4 car lengths long, it's little more than a transition between the left-hand sweeper before it and the right-hand sweeper afterwards. I have my foot to the floor for about the first half, then slam on the brakes during the second half. I re-learned yesterday that it's essential to brake in a straight line, even with ABS; otherwise extreme oversteer can arise in the turn. That will not speed up your time, even if it does look cool.
  5. Next up is a right-hand sweeper of about 120 degrees that turns you back up the hill you just came down on the straight, and it's mostly off-camber. Again, the last pair of cones are the important ones, and I watch those during the entire turn. I think the off-camber-ness of it throws me off, because I can never execute this turn as well as the one before it. I usually end up understeering, pushing the car out to the outside turn. You could argue that I should really aim to arrive next to the inside cone, which would give me a better entry into the next element, but my approach allows me to carry more speed through the sweeper and doesn't impair my entry into the next element too greatly.
  6. The sixth element is a 3-cone slalom that takes you over the crest of the hill and down the far side. Like before, this slalom ends on a left-side cone and feeds into a left-hand sweeper, so the last cone doesn't matter so much. I'm usually at wide-open throttle through the last 2 cones and on the rev limiter by the last one.
  7. The following element is a left-hand sweeper of around 70 degrees that takes you down to the lowest point on the course. Because you are carrying so much speed out of the slalom, and are on the gas through most of this turn, you reach the highest speed of the course at this point. I'm usually on the rev limiter throughout most of this turn. Then you brake, hard, down to the slowest speed of the course in order to execute the following element.
  8. The eighth element is a sharp, off-canber left-hand turn of about 120 degrees that points you back up the hill. This is the point where you must "be slow to go fast;" you have to be patient here, going easy on the throttle in order to arrive at the final inside cone---again, the only one in the turn that really matters---at the correct position and angle to enter the next element. This is probably the hardest element on the course for me.
  9. Next is a single cone followed by a "hallway" of 6 cones, both going uphill. You must pass to the left of the cone, then enter the hallway, which runs off to the right. The difficulty here is that you need to be coming out of the hallway pointing to the left. Thus, you must pass on the left of the cone, then curve to the right to enter the hallway from right to left, at an angle of about 40 degrees with respect to the "walls" of the hallway. Well, it's 40 degrees in my little car. The hallway is pretty narrow, so if you are in something like a Corvette, you're forced to drive at a shallower angle. I think I usually lift off the throttle when setting up for the set of 6 cones, but I don't actually use the brake. I think.
  10. Element 10 is a single left-pass cone with 6 or 7 cones forming a 40- or 45-degree arc to the cone's left, all still uphill. The idea here is clearly to pass between the single cone and the arc, but you want to pass just to the left of the single cone and just to the right of the last cone in the arc. I usually brake as I enter the arc, then ease on the throttle as I pass through it.
  11. The final element is just a short uphill shot to the finish, which consists of a set of cones marking the timing lights that stop the clock and a "chute" of cones. The chute is a tapering S-curve that forces you to slow down to the walking pace mandated when not on the course. You need to be at full throttle from the end of the arc up to the timing lights, but, since that path is gently curved to the right---at least the way I drive it---you need to be careful not to understeer out and hit the left finish cone.
That's the course. As I remember it anyway. I hope this post has helped you understand what autocross is about. If you are wondering if you should try it, I say sign up for a competition or a class to find out. You could also just show up and watch an autocross for free.

2 comments:

  1. jamaal8:08 PM

    Skeeler,

    I find it interesting that your AutoX course description, which takes you 36 seconds to drive, takes me 5 minutes to read.

    Please post a movie!

    ReplyDelete
  2. Jamaal,

    Good to hear from you! It's been a while.

    As for the length of the description, well, there's a lot happening in a short period of time. You should read a description of the Olympic lifts, especially the snatch. The snatch takes 2 seconds, but I know I've read an article on it that's several pages long.

    I don't have any movies sadly. I was too busy driving to work a camera.

    ReplyDelete