The 1974 911 Carrera RSR Turbo was a sort of work in progress, put on track by Porsche to gain experience in view of the Group 5 regulations which would come into force from 1976. On the Carrera Turbo, entered in the prototype category, the Works experimented various solutions that would be useful in the development of the Group 5 935. The Carrera RSR Turbo was powered by a supercharged 500-horsepower 2.1 engine, despite the evident disadvantage toward open sports cars, specifically conceived for the category, the RSR did quite well, also finishing 2nd overall at Le Mans. Having accomplished its main task, the RSR Turbo also made some outings in IMSA with Ted Field and the Vasek Polak team.