| Mercedes-Benz C111/II | |
| Manufacturer: | Daimler-Benz |
| Production: | 1970 (16 cars produced) |
| Assembly: | Untertürkheim |
| Designer: | Bruno Sacco |
| Class: | Sports car |
| Body Style: | 2-door berlinetta |
| Layout: | Longitudinal, Rear mid-engine, rear-wheel drive |
| Transmission: | 5-speed manual |
| Wheelbase: | 2620mm |
| Length: | 4440mm |
| Width: | 1800mm |
| Height: | 1120mm |
| Predecessor: | Mercedes-Benz SL-X |
| Successor: | Mercedes-Benz CW311 Mercedes-Benz C112 |
| Doors: | Gullwing doors |
The Mercedes-Benz C111 was a series of experimental automobiles produced by Daimler-Benz in the 1960s and 1970s. The company was experimenting with new engine technologies, including Wankel engines, diesel engines, and turbochargers, and used the basic C111 platform as a testbed. Other experimental features included multi-link rear suspension, gull-wing doors and a luxurious interior with leather trim and air conditioning.
The first version of the C111 was completed in 1969, and presented at the 1969 IAA in Frankfurt. The car used a fiberglass body shell and with a mid-mounted three-rotor direct fuel injected Wankel engine (code named M950F). The next C111 appeared in 1970; it was shown at the 1970 Geneva International Motor Show. It used a four-rotor engine producing 260abbr=onNaNabbr=on. The car reportedly could reach a speed of 300km/h.[1]
The company decided not to adopt the Wankel engine and turned to diesel experiments for the second and third C111s. The C111-IID's engine was a Mercedes-Benz OM 617, and produced 140kW at 4200 min-1. It was based on the Mercedes-Benz 85 kW variant of the OM 617 used in the Mercedes-Benz W 116 S-Class, but had a different turbocharger without a wastegate, which allowed an increased pressure ratio of 3.3. Daimler-Benz also added an intercooler that significantly improved the engine's thermal efficiency.
The C 111 III prototype that was completed in 1978, had a more aerodynamic bodywork that gave it an air drag coefficient of 0.195. It had a modified 3-litre version of the Mercedes-Benz OM 617 five-cylinder Diesel, now producing, and a BMEP of 1.68 MPa, resulting in a maximum torque of 401 N·m at 3600 min-1. It enabled the C 111 III to reach a top speed of 338abbr=onNaNabbr=on at the Nardò Ring in 1978, and also to average a 16 l/100 km fuel consumption at an average speed of 325 km/h.[2] The engine was fitted with an M-type inline injection pump of Bosch's PE series with a maximum injection pressure of 40 MPa.[3]
A later 4.5 L twin KKK-turbocharged V8 version that produced 368abbr=onNaNabbr=on at 6000/min set another record, with an average lap-speed of 403.78 km/h (250.958 mph). This was achieved by Hans Liebold in 1 minute, 56.67 seconds on May 5, 1979.[4]
Total production was 16 cars: 13 first and second generation Wankel engined cars, two diesel engined third generation cars used in the Nardò record attempt, and a single V8 engined fourth generation car.[5]
Mercedes-Benz introduced the C112 at the Frankfurt Motor Show in 1991 as a proposed production sports car. The car used a mid-mounted 6.0 L V12 engine. After accepting 700 deposits, the company decided not to proceed with production.