DIRTY AIR

'G' IS FOR GROUND EFFECTS.

- Fred Smith

LEFT TO ITS OWN DEVICES, any auto-racing concept will become too expensive, dangerous, and uncompetitive to stand as a thriving business for all involved. The racing world has known this since at least the Seventies when the gas crisis hit at the same moment car builders were running out of relatively easy ways to add speed at tracks like Le Mans and Indianapolis. This has become more true with the passing decades, making raw innovation increasingly difficult. Rules became ever more stringent, and for a while the racing was closer and more entertaining. That came to a halt across all of NASCAR, IndyCar, and Formula 1 about 20 years ago. The culprit? Dirty air.

The key principle guiding every modern racecar design is grip. Grip comes largely from downforce, which is produced on modern racers by managing the air through which they travel with wings, flaps, and shaped body components. For a single car, the only drawback is drag. Introduce a second car, and the problem becomes apparent.

The air pushing a car into the pavement is disrupted, creating turbulence behind it. When a trailing car attempts to follow closely, that air cannot reorganize quickly enough to create adequate downforce. The effect benefits the leading car and harms the car following. It's a problem that discourages the most exciting thing in racing: passing.

In 2021, Formula 1 champion Max Verstappen called it an issue "at almost every track" where the series raced. "As soon as we get within two seconds, the car is really difficult to drive, and we lose a lot of downforces," he said.

A similar problem popped up in both NASCAR and IndyCar, where designers had less freedom but always pursued more downforce, disregarding the effect on a trailing car. After all, if your car is leading a battle for position, dirty air behind it is an advantage.