This is a totally newbie question from someone with no engineering knowledge - but curious about automobile aerodynamics.
Most of this great thread are eco-mods to 1) reduce drag, and 2) sometimes to increase downforce or wind-flow around the car.
Can a car use a wing or body-shape at higher speeds for LIFT to reduce the weight to improve fuel economy - or would the lift reduce traction and be a safety hazzard? Just curious why not have adjusting wing so at high driving speeds (70mph) your car is made a bit lighter (lift) and uses less fuel - or would this also produce drag. Perhaps adjustable wings could move to a lift position at high speeds, a neutral level slower or angle to increase down-force in rainy conditions? This prolly just shows my lack of knowledge of the physics of car aerodynamics at 70mph.
http://www.speedace.info/solar_cars/...owered_car.jpg