This paper presents a study developed in order to improve the aerodynamic performance of an automotive prototype by means of simulations carried out by a software that makes of the finite volume method. The prototype will be built at the Laboratory of Automotive Engineering of the Lutheran University of Brazil - ULBRA. Taking into account the original design of the automotive prototype, three virtual models were generated and analyzed. There were three steps to simulate the aerodynamic behavior on a 3D model: generation of the geometry with the employment of CAD software, generation of the mesh for the faces and volume that involve the car, using specific software, and solving the flow, with a CFD software. The results of the analysis allowed identifying the model with the lowest aerodynamic drag. That model had some modifications on its design, when compared to the original one, like wheels and their housings. Also, an air deflector was included on the back of the virtual prototype, in order to reduce the drag. The results obtained were reasonable, because of the deflector, which gave a drag reduction around of 6%.