The company decided not to adopt the Wankel engine and turned to diesel experiments for the second and third C111s. The C111-IID produced 140 kW (188 hp) and was based on the 240D 3.0 W115 model OM616 engine. The C111-III was powered by a 170 kW (228 hp) at 4,500 rpm straight-five OM617 turbocharged diesel that broke nine diesel and gasoline speed records.