Pops,
If you are talking aero you might mean the Center of Pressure. This is point that is very much like a Center of Gravity. It is the imaginary point that you could apply a force that is equal to all of the aero forces being applied to the car and have the same affect as the aero forces. Now this point is related to which view of the car that you are looking at. Normally it is the side view because the location of the Cp in that view related to the Cg is very critical to the straight line stability of the car. You want the Cp to be behind the Cg. The more the better. This is why vertical fins are added to cars at the back and why darts are so stable.
Rex
