mcrat here read this article maybe im misunderstanding .....
In truth, aerodynamic forces increase in an exponential manner. In this particular case, the aerodynamic drag forces increase by the square of the rate of speed change. An increase in speed of 6 times, from 10 mph to 60 mph, would increase the force by 36 (6 squared, or 6x6) resulting in an increase of the force on your hand from 2 lbs. to 72 lbs. (36 x 2 lbs.). This is the main reason why cars run into an "Aero Wall" with increasing speed.
Drag horsepower - Another important fact is that the horsepower required to increase the speed of the car (and overcome drag) is also increasing at an exponential rate. In this case, drag horsepower increases by the cube of the speed change. Using the same example, your hand carries 2 lbs. of drag force at 10 mph. This equates to just .053 drag hp, certainly not a lot of drag horsepower! Let’s increase the speed by 6 times to 60 mph and see what happens. We already know that the drag force increases from 2 lbs. to 72 lbs. Using the cube of the speed change (6x6x6), times the original drag horsepower (.053), the drag horsepower increases to 11.5 hp (.053 x 6x6x6 = 11.5). This is the clearest example of why aerodynamic drag is so amazingly critical to racecar performance.