How does this product work? The gurney flap is a projection on the trailing edge of the pressure side of the rear wing. It modifies the airflow across the wing increasing the pressure on the top side of the wing. Downforce is increased without a corresponding increasing drag.

Can you briefly explain aerodynamic lift, downforce, and drag as it affects a car? Aerodynamic lift occurs when air pressures acting on the bottom side of the vehicle (or component) are higher than that acting on the top side resulting in a net upward force. Downforce is negative lift. The lift forces add or subtract from the forces affecting the tire contact patches and therefore will alter available traction. The distribution of lift will affect the handling balance if the effect on the front and rear wheels is not equal. Drag is a measure of the air resistance acting on the vehicle. Lift, downforce, and drag forces increase exponentially with speed.