Rear Diffuser

Vertical fins called strakes guide the airflow. It works best with a flat, closed underbody. On many road cars the diffuser look is mostly styling. Electric cars often have smooth underbodies, which helps them make use of a diffuser to reduce drag.

Expanding the air gradually as it exits slows it down and lowers the pressure under the car.

Fake diffusers on everyday cars add little aerodynamic effect. Damage to underbody panels can reduce the diffuser’s effect.