Track testing of race cars is expensive and racing series typically limit the amount of testing that can be done on circuit tracks. Because of this, we saw the need to develop a computer model that could simulate a car on a track with any specified surface roughness and with aerodynamic loading acting on the vehicle. This model allows an analysis of the effect of aerodynamic loading on the vertical dynamic response of the vehicle. Vehicle parameters specific to an IMSA GTP car including aerodynamic data from wind tunnel testing and nonlinear shock characteristics were used in this study. Simulations were run for various speeds and ride height configurations and it was found that very small changes in the static settings of the front and rear ride heights can lead to large differences in the resulting ride heights at speed. This can be attributed to the variations in the nonlinear aerodynamic loading as the ride height and speed of the vehicle change. This model was also used to investigate the “porpoising” phenomenon in which a vehicle experiences large pitching oscillations. An attempt was made to see if the dependence of the aerodynamic down force on the rates of change of the sprung mass ride heights could lead to these large oscillations of the vehicle. However, results on porpoising were inconclusive mainly due to the lack of data on the aerodynamic “damping” effects.