The Double Diffuser
POST #1 - Aero 5/5/25 The Double Diffuser: How Brawn GP’s 2009 Innovation Changed F1 In 2009, Formula 1 saw one of its most remarkable underdog stories when Brawn GP, a team that nearly folded before the season began, dominated the championship. At the heart of their success? A clever aerodynamic device: the double diffuser. What Is a Diffuser? First, a quick refresher: the diffuser is the rear part of an F1 car’s underbody. Its main job is to accelerate airflow under the car , creating a low-pressure zone that increases downforce —pushing the car harder into the track for better grip. The diffuser works on the principle of the Venturi effect : as the cross-sectional area widens at the diffuser exit, air pressure rises and velocity drops, helping to “pull” more air through the underbody. This smooth exit flow is crucial for maintaining efficient ground effect. The 2009 Regulations In 2009, F1 introduced new aerodynamic rules to reduce downforce and improve overtaking. Thes...