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Having a well-balanced suspension in race cars is critical to a team's success in every race series. The ability of the suspension to keep all four tires in contact with the racing surface over bumps and through turns is crucial. A key component controlling these factors is the dampers. One method used to assess the damper performance, besides on track testing, is the four post vibration rig test. This test involves placing the vehicle on a four post test stand that inputs prescribed forces to the four tires. Acceleration measurements are made on the car during this test and frequency response plots can be generated to evaluate the vertical dynamic response of the vehicle. While very useful, the four post rig testing is expensive both in terms of race team time and costs.

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.