Introduction to Autocrossing
An Autocross is a course of left and right turns defined by cones where the designed maximum speed is 100mph. A typical course takes from 50 to 90 seconds to complete. The goal of each participant is to manuver through the course in the fastest possible time without hitting any of the cones. Note: the flimsy rubber cones don’t do any damage that can’t be waxed off and all driving or riding participants must wear helmets.
What to Expect
Arrive about 30 minutes early. Find and sign in on the insurance waiver form. Take time to walk the course and talk to other drivers. While walking the course, imagine where you will brake, turn in, and exit each corner, keeping in mind the next corner. Each car is safety inspected before the event starts. A drivers meeting will provide any details of the course or event. After the drivers meeting everyone will assemble and take a parade lap. This is your opportuninty to familiarize yourself with the course at a slow speed (parade laps are limited to first gear). Drivers will be divided into 2 run groups. Each driver gets 8 total runs or laps through the course in two 4 lap sessions. While one group is making their 4 runs, the other group of drivers work the course. Working the course means notifying the time keeper of, and resetting any downed cones. First time drivers are allowed an instructor for the first couple of laps (just ask).
Preparing Your Car
To prepare your car for an autocross is not much more than checking items that should already be in good working order. The battery shouldn’t be loose, the seat belts functional, brakes working, fluids topped up, no cord showing on the tires,and lug nuts properly torqued. The only things out of the ordinary for autocross is to remove all loose items from your car, and the driver must wear a helmet. Novice drivers should inflate their tires to 4 psi above recommended cold pressure (typically 40 psi).
Make yourself comfortable in your car. The pedals should be easy to reach and your arms bent. (holding the steering wheel at 9 and 3 you should be able to turn the wheel 180 degrees with your shoulders on the back of the seat.) The key is to be comfortable and smooth.
When you buckle your seat belt, move the seat back a little, pull the belt tight. Yank the belt firmly to engage the cam lock so the tab just touchs the latch. Insert the tab in the latch and move the seat forward to your comfortable driving position. The belt should be tight enough to keep the cam locked. This may take a few tries and is a LOT easier with electric seats. Being tightly belted in, you can concentrate on driving, not holding yourself in the seat.
Your hands should be at 9 and 3 on the wheel. On the tight turns of the autocross course you will be doing a lot of shuffle steering. You should keep at least one hand on the wheel at all times, and try to maintain the orginal 9 and 3 positions for orientation reference. The spokes on the wheel really help as a guide.
Braking is done before you enter a turn, while still going relatively straight. The key to braking is to brake with a little jab then apply the brakes in ernest. The jab transfers the weight to the front wheels. If you jab too hard you will lock the front brakes as you jab. If you jab to softly you will lock the front brakes as you brake harder. When practicing braking technique on the street, always check the mirrors first. That car in the mirror will probably not be able to stop as quickly.
Braking is also the time for downshifting to the proper gear for the corner. In fact all downshifting is done during braking. When braking, brake with the middle of the ball of your foot on the right edge of the brake pedal, and heel firmly planted on the floorboard. It will feel like you are braking with the ball of your big toe. As you slow, push in the clutch while moving the shift lever to neutral. Roll the right side of your foot down and blip the gas pedal. As the rpm goes up, move the shifter to the next lower gear and release the clutch smoothly. The idea is to match the engine rpm to the lower gear and car speed before letting out the clutch. It takes a lot of practice to get timing and smoothness down. When you get it right you will notice how it goes into gear a lot smoother and faster. Practice the pedal action first in your garage with the engine off to get the feel. When you first try it on the street, you might want to find a deserted street or parking lot! To much or too little thottle blip will cause the rear wheels to break loose. It will also take a little practice to keep braking smoothly as you blip the throttle. The neat thing is once you get the hang of it, you can practice downshifting any time you drive your car.
Cornering is choosing a line and managing weight transfer. Choosing a line is making the turns larger by entering on the outside edge, turning to the inside edge and exiting twoards the outside edge. The cones are guides and don’t necessarily mark the beginning, middle or end of a turn. Managing weight transfer amounts to starting the turn-in as you smoothly left off the brakes. This gives the front tires more grip by using the weight already on the front from braking. After letting off the brakes move to the throttle and slowly apply just enough throttle to maintain speed through the middle of the turn. This transfers the weight to the cars balanced position with most of the weight on the outside tires. Just before you start to straighten the wheel smoothly go to full throttle. This transfers the weight to the rear for acceleration. As you go through a turn, feel the weight transfer smoothly from the front during braking to the side as you enter the turn, then to the rear as you exit. Practice, practice, practice, and remember smoothness is the key.
There are two things that will happen in the corners that slow you down. Understeer and Oversteer.
Understeer, also called pushing or plowing, is the most common for first time drivers. Understeer is when you apply the gas in a corner and the front of the car starts sliding straight. It is caused by accelerating too much to early in the corner. To stop the sliding, let off the throttle and straighten the wheel a little until the front tires stop sliding. You may even need to add a little brake, very smoothly as you straighten the wheel. Once the sliding stops you can turn back in and finish the corner at a slower speed.
Oversteer, also called getting loose. There are two types of oversteer, power oversteer and simple oversteer. The most common and considered a lot of fun for new and experienced drivers alike is power oversteer. Power oversteer is when you get on the gas too quickly with a lot of power, the rear tries spin and the rear comes around because there is not enough weight on the rear for traction. Since you can’t let off the brakes or add throttle to add weight to the rear, just steer into the skid and try to smoothly and slowly give a little less gas, but don’t lift off the throttle too much or you will enduce simple oversteer and spin out before you can correct it. Simple oversteer is when you turn in for a corner too fast without letting off the brakes enough or lift the throttle to quickly while turning and the rear comes around. This happens because there is not enough weight on the rear tires to hold the turn. Steer towards the skid, let off the brakes, and add a little throttle, but not too much throttle or you will enduce power oversteer.
What to bring
The list of things to bring to an autocross depends on your skill and participation level. All that is really important for a first time participant is: Yourself, your car, water to drink, some sun protection and comfortable clothing (preferably cotton). If you have your own helmet, bring it. There are usually helmets available to borrow, but it is nice to have your own. More advanced participants also bring: tire gauge, air pump, towel, sticky competition wheels & tires, jack, torque wrench, lawn chairs, camera/camcorder, wife, kids, friends, and neighbors. Rememeber it is easiest to remove loose items before you leave home.
See you at the Autocross!