Schuppan has had a very successful sports car career, winning the 1983 24 Hours of Le Mans for Porsche's official factory team with Al Holbert and Hurley Haywood in a Rothmans Porsche 956 (#3).
Schuppan tivo unha exitosa carreira deportiva, gañando as 24 Horas de Le Mans no equipo oficial de Porsche con Al Holbert e Hurley Haywood nun Rothmans Porsche 956 (#3).