Reprinted from i Saluti, June 1997

Autocross Fundamentals

by J.D. Crownover

Are you interested in autocrossing, but still a little hesitant because you don’t know what to expect when you show up? Here’s some guidance to get you through that first race. Around St. Louis, most of the courses will be completely laid out with cones so you can’t get lost.

The cones are the bright orange traffic cones you see around construction sites. A single cone indicate you are to pass on one side of it, which side is usually obvious. Single cones are used on both sides of the course, as though along the shoulders of a road.


Double cones are used to mark the entrance or exit of a “gate”. There will be two sets of double cones, one set on either side of the course, and they will be aligned perpendicular to the direction of travel. Think of these as the frame to a doorway.


Three cones may be used to mark the corner of an intersection. Sometimes, the course crosses itself. The three cones will be in a “V” as the two gates it signifies share the corner cone.


A single cone laying on its side means “go that way”. Think of the cone as an arrow and go the way the point points. (Sorry about that.) Pointer cones are used to indicate mandatory direction of travel.

Most of the course will be laid out like a road racing course, just a lot of turns, and you simply drive through as fast as you can. (Penalties explained later.) However, there are a few special layouts which you may encounter, and you’ll need to know how to drive them.

Start/finish Line

The start and finish lines will be indicated either by one or two cones taller than the rest, or by three cones in a line on either side of the line. The start and finish lines may be the same line or may be in two separate locations. Whichever, you normally have a staging area and a run-off area. The staging area simply means you are started some distance from the starting line. Cones will still mark the way, but your time doesn’t start until you actually cross the start line. The reverse is true at the finish line. Your time stops when crossing the finish line, not when the cones stop, so Slow down!!

Slalom

If the course suddenly “ends” (there’ll be a gate) and beyond you see a single line of cones spaced some distance apart, you’re at a slalom.


The idea is to pass between each “pair” of single cones, so you’ll have to drive between cones 1 & 2, then 2 & 3, then 3 & 4, etc. In effect you are alternating between passing a cone on one side and passing the next cone on the other. If the first cone is standing there all by itself, it’s an optional slalom. This means it doesn’t matter which side of it you pass on, but you must alternate for all the following cones. If in front of the first cone there is a cone laying on its side (a pointer cone), this means you must pass the first cone on the side the pointer cone indicates.


Cul de sac (Circle)

The cul de sac is used to reverse direction of travel. The course will end (the circle may be marked with cones) and there’ll be a single cone all by itself. The idea is simply make a U-turn around the cone and the run the course backward. Which way you turn is optional, unless there is a pointer cone present.


Peterson Box

The box will be defined by gates at either end. In the middle of the box will be a single cone. You are to drive through the box without hitting the single cone, so you’ll have to veer around it on one side or the other. Your choice.


Y-Intersection

A Y-intersection is sometimes used when a course is run more than once per turn. The “V” of the Y will be marked with three or more cones and pointer cones may be on both sides indicating travel in both directions. The sequence in which to go will be provided at the driver’s meeting.

Penalities

There are two major sources of penalties in an autocross:

  • Cones --Hitting a cone entails a penalty, normally two seconds added to your time for each cone hit. For a cone to “count” (toward the penalty) it must be either knocked over or standing completely out of the box. When a course is made, chalk is used to outline the base of the cone. If you hit a cone and it remains upright and any portion of the cone still touches the box, it is not a penalty. Even if you have hit the cone and it stood back up. But a cone laying on its side, even if it’s in the box, counts. With two or more cones marking a gate or intersection, each cone hit counts. However, pointer cones do not count.
  • DNF --This means Did Not Finish, and is actually a misnomer. It is used to mean you didn’t finish, your car broke down or something, but it usually means you got off course somewhere. Some common ways to get off course is to pass through the wrong single cones outlining the course, failing to slalom properly, going on the wrong side of a pointer cone, or going the wrong way at a Y-intersection. Also, some courses may designate that hitting a cone after the finish line is a DNF. (This is done when it’s really important to slow the cars down at the end of the course.) If you do get off course, you are allowed to reenter the course at the same place you left and you are then not assessed this penalty. (The extra time to get back on course is penalty enough.)
  • DNS --oh yeah, there’s also a Did Not Start. This is used literally to show you did not start your run when it was your turn.

As you can see, you don’t want to get any cones in autocrossing. These add seconds to your run time. But you really don’t want to get a DNF, then you don’t get any time whatever. So if you are headed off course, say you entered a corner too fast, go ahead and hit the cones rather than driving outside the course to avoid cones. At least you’ll get a time. The biggest help you can give yourself when starting out is to show up early (8:30 - 9:00 most places), walk the course with someone (even if you only follow them) and attend the driver’s meeting. Then, just get out there and pretend you’re late for work.

   
  from Sotto Veloce, AROC Chicago

Better Autocross or Track Performance with Chalk

In general tire air pressures between 35 and 45 psi are used for performance driving events. The higher than normal pressure will improve steering response, cornering traction, overall handling and tire performance.

The optimum air pressure depends on several factors including tire size, tire temperature, air temperature, driving style, track conditions, vehicle weight, and suspension settings.

To help determine the optimum tire pressure for time trials or autocross events all you need is a piece of chalk! Begin by rubbing the chalk on the sidewall of the tire and then move up to the tread blocks found in the shoulder area.

After you’ve chalked all four tires in various places around the tire’s circumference, take the car out for a few practice laps or perform some hard cornering maneuvers in a safe area.

Next, inspect the chalk marks and determine if any pressure changes need to be made. What you’re trying to achieve is to have the chalk rubbed off close to where the tread design ends in the shoulder area of the tire. If all the chalk is rubbed off a tire, add air pressure to the tire. If, on the other hand, most of the chalk is still on the tire, reduce the air pressure in the tire.

When adding or reducing air pressure to maximize performance, do so in 2 psi increments. Even minor changes in the air pressure can make a substantial difference in the way a car performs.

You can then fine tune the car’s handling by adding air pressure to the end of the car that needs additional traction. So, to reduce understeer add air pressure to the front tires.