An Autocross is a race against the clock (as opposed to wheel-to-wheel) around a unique course defined by cones or pylons, usually taking place on airport runways, parking lots, or any large paved area.
As an entry-level form of motorsport that focuses on driver skill and car control, almost any passenger car can be entered into competition. All that is required to enter an event is a valid driver’s license and usually some form of membership in the organizing club that helps to cover operation and insurance costs. Entry fees are also the lowest of any motorsport, making it a great discipline to get started.
Like rally racing, competitors stage their vehicles before the timer starting sensor, and attempt to navigate the course in the shortest amount of time. There is usually a single line around the course, which is denoted by a combination of stand-up cones as well as lay-down or ‘pointer’ cones. Unlike rally racing, courses are unique and designed to be used one-time during an event. One year, the SCCA Solo Nationals results were called into question when the course layouts were released early enough for one regional club to controversially build and practice on courses that approximated them.
The average autocross course is approximately 60 seconds in length for most vehicles, and a 2 second time penalty is assessed for each stand-up cone that is knocked over or moved outside of a marked box. Pointer cones are not assessed a time penalty, however they are always placed in a manner that signifies a more serious navigation error if they are displaced.
If the driver drives around the incorrect side of a cone, they are deemed to have driven off-course and are scored a ‘did not finish’ (DNF) instead of an official run time. Times with penalties or a DNF are commonly referred to as a ‘scratch’ time.
Courses are designed so that the vehicles are limited to lower speeds, requiring only a legal helmet and basic restraints for driver protection. Most vehicles spend the majority of the time on course in 2nd gear.
In autocross, a greater importance is placed on the suspension and handling characteristics of the vehicle instead of on power output. This is due to the fact that there are seldom any ‘straights’ in autocross, and the vehicle is constantly turning. The frequency of driver inputs is quite high, requiring 1 input per second on average. This is contrasted with road-racing, where several seconds can pass before a driver input is required.
To provide a competitive playing field, vehicles are classified into classes, commonly under the Sports Car Club of America (SCCA) classing rules. Classes are grouped together into heats where they line up to run the course. Car classes cover a broad range, from factory ‘stock’ classes to ‘modified’ classes containing purpose-built race cars that are not street legal.
For safety reasons, usually no more than 2 or 3 cars are allowed on the course at a time. Drivers are given at least 3 runs on the course in each heat, and each heat will run the course at least once per day.
At a national-level 2-day competition, such as a SCCA Championship Tour or Solo Nations, each driver is given a single heat per day in order to make 3 runs on the course. The 2nd day of competition usually runs the same course backwards, but at Solo Nationals there are 2 separate courses.
Local, ‘club level’ races will commonly offer more than 3 runs per heat in order to provide greater practice time, however the goal of a competitive autocross is always to ‘get it done in 3 runs’.
After racing in a heat, drivers will fulfill a number of work positions ranging from resetting and reporting on cones hit on course, to running event timing, announcing, or ensuring that all people entering the event site have signed an insurance liability waiver.
In order to compare vehicles across classes when running in local races, an indexing value called PAX is maintained by SCCA members. Local clubs will often have PAX-based class groupings in order to provide competition among smaller classes. There are usually local PAX groups for nationally-competitive drivers so that they can compare their performance to others of the same skill level, while not intimidating more casual drivers competing at the class level.
Up to 2 drivers can officially enter in a single vehicle in the same heat. These are commonly referred to as ‘dual driver’ vehicles, and are sent around the course twice as often as the single-driver vehicles, with the 2 drivers switching in-between runs.
Running a 2-driver team is very advantageous as it can quickly heat the vehicle tires allowing for a higher tractive capacity. Drivers can also review logged and video and learn and grow from each other.
SoloStorm Data Logger and Analysis Software for Android offers several optimizations for autocross racing. First, it allows the driver to review logs and videos immediately after a run, while they are waiting to take their next run. After adjusting tire pressures and changing vehicle numbers (2 driver cars), drivers can spend a significant amount of time deciding on what experiments to try for the next run.
SoloStorm also allows a list of drivers to be defined, which will be automatically rotated through after each run. This is one less thing that competitors need to worry about during a busy day.
Autocross is also a very social form of motorsport, where the fiercest competitors can be the best of friends and spend social time together during and after the race. This provides an excellent opportunity to use SoloStorm with Petrel Cloud in order to share logs and videos, and learn from one another.