The aspiration phenomenon in NASCAR
34 of the 36 Sprint Cup races are organized on ovals, except two on road circuits. For this reason, cars are created to roll flat out and be as stable as possible in banked corners.
Although devoid of spoiler, the Sprint Cup cars still generate aerodynamic downforce and are sensitive to the gigantic turbulence created by the other cars on the track.
Downforce is a vertical force, produced by high-velocity airflow, which pushes the car towards the ground. This increases the grip of the tires, which allows you to drive faster in the turns.
The concern of the support is that it unfortunately generates a drag; turbulence that naturally slows the car and increases fuel consumption.
These disturbances allow two or more cars that are placed one behind the other to travel faster than one alone. The first car in the train pierces the air, while the others ride in a kind of ‘vacuum’ of air, which allows them to reach a higher speed. We are talking here about the phenomenon of aspiration, known in English as ‘drafting’. Thus, a tight pack of several cars drives much faster than a single car.
This suction phenomenon plays a critical role when racing stock cars on ovals. It is essential to stay in the peloton, because once ejected from the train, the racing car instantly loses speed and tumbles several places.
For the engineers and the crew chiefs, this poses a major problem, because the driver must be offered a car that is as fast as it is stable, whether driving alone or in a peloton.