:The objective was to determine the effects of dirt track geometry, the driver's elliptical path, and the car parameters on lap time. A dynamic simulation model was developed to: 1) investigate variables over which a racing team has control for a Late Model Class car on a short dirt track, and 2) compare them to actual field observations at a local track. The suspension dynamics were not included; overall tire COF (Mu) was used. Designed experiments predicted lap time. Considered were car mass, rotating mass, gear ratio, Mu, engine torque, aerodynamic & tire drag, track geometry, and elliptical path axis angle.Mu was critical. Matching tires to track surface dominated reducing lap time, followed by driver judgement on braking point. Slight differences were significant. Simulation times compared well with the fastest cars.Quantitative performance data on dirt tires is needed.