Autocross
From Bellybuttonporn
May 23, 2007
A couple weeks ago I took my new Magnum autocrossing. I haven't been in a blogging mood, so I've got plenty of stuff saved up to talk about. Since I'm currently ducking out the brunt of the hailstorm running through Iowa by hiding in a parking ramp, I've got some time. I'm sure I already told a lot of you about the gallery, but for the rest of you here it is again, with the story.
Autocross is like racing, except you (typically) take your regular car to the competition. Also, there's no other cars on the track or at least they're spaced out so you can't run into each other. There aren't really any winners or losers. They time you going around the track and you try to beat your best time. If you're really good you can try to get the best time of the day, but really it's comparing apples and oranges so the number doesn't really mean much. But you get bragging rights.
This event took place in Marshalltown and was put on by MCCI (Mustang Club of Central Iowa). Being a non-member, it cost me $25. The event goes down at a go-kart track which is about 2 lanes wide, so just big enough to move a car around. Normally they have some kind of rigid setup because there's lots of people there. But since it was raining a lot (kinda like today) only about 15 people showed up. So we each got to go out on the track a lot.
It was raining cats and dogs so it was a great chance to get to know my car. My car is rear-wheeled drive, but also has an electronic stability program (a.k.a. traction control). What this means is when my car senses its wheels sliding around, it uses the brakes and throttle to keep the car stable. This both helped and hurt me while autocrossing, as I'll explain later. Later on it dried up and then I could really start to push things.
During a few runs I had passengers. Some times they rode along just for fun, and some times they took videos. Here's the videos of me:
- May 6 2007 MCCI autocross, Marshalltown, Ia. Shot by Steve
- May 6 2007 MCCI autocross, Marshalltown, Ia, In-car 1. Shot by Steve
- May 6 2007 MCCI autocross, Marshalltown, Ia, In-car 2. Shot by Sam (google video)
The traction control really helped me out in the beginning to keep the car on the track during the worst of the storm. As you can see from the map there are lots of turns in the track so lots of opportunity to go off the track. Once the track dried out a bit I started feeling constrained by the traction control. When going around a corner, a real-wheel drive car will tend to oversteer (a fancy name for spinning around more than you turn the wheel). In contrast, a front-wheel drive car will understeer (it'll try to go in a straight line when you turn the wheels).
Well, on a twisty track like this I should have a nice advantage in rear-wheeled drive because oversteer would let me get around the corners faster. My normal instinct when I think I can't make a corner is to let go of the gas and hit the brakes. However, to get around the corner better in a rear-wheel drive car you should stay off the brakes and give it a little gas to break the rear end loose so it starts sliding around (that oversteer thing I described earlier).
However, when I'd try that the back wheels would slide (according to plan!) and the traction control would apply the brakes and cut throttle (not according to plan!), which would make the car try to plow off the road just like if it were front wheel drive. There was one time when I did drive off the track because of that. I was able to get back on without being stuck in the mud, so no harm done. From then on I tried it a couple times without the traction control. Much better!
This was my first time autocrossing. This is my first high horsepower rear-wheel drive car. This was my first real event with my car. A lot of firsts, but it was all so fun. I want to do more and more and more!
