An environmental wind tunnel for producing air flow over an automotive vehicle includes a source of air under pressure and an elongated housing for receiving an automotive vehicle. The environmental wind tunnel has an upstream end coupled to the downstream end of the source of air under pressure, so that air is blown axially through the housing from its upstream end to its downstream end. The environmental wind tunnel also includes a large area ratio contraction with large area corner sections, large area duct work with a low angle diffuser, a large area fan, and acoustic treatments on the turning vanes, test chamber walls, and corner duct interior surfaces. In addition, in-flow acoustic absorption panels, and one or more flow conditioning screens may also be included in the environmental wind tunnel.