The extensive use of wind tunnels in the aerodynamic development of race cars started during the 1970's. At this early stage, large gains in performance could be achieved using simple models and standard testing techniques. However, with continuing development the gains that could be achieved became progressively smaller as the overall aerodynamic performance improved. This has required the development of complex, fully representative models which include, for example, correct radiator simulation and working suspension. The need for detailed aerodynamic data has resulted in the employment of advanced testing techniques. In addition to accurate force and surface pressure measurements, the flowfield characteristics around the car are measured using a laser doppler anemometry system.This paper presents a description of current testing techniques employed in the development of the Penske Indy Car during tests in the University of Southampton 3.5m x 2.6m wind tunnel.