NSU Ro 80
|NSU Ro 80|
|Manufacturer||NSU Motorenwerke (1967-1969)
Audi NSU Auto Union AG (1969-1977)
|Body and chassis|
|Body style||4-door sedan|
|Engine||2 x 497.5 cc two-rotor Wankel engine, 115 PS (85 kW; 113 hp)|
|Transmission||3-speed Fichtel & Sachs all-synchromesh manual connected with automatic clutch and F & S torque converter|
|Wheelbase||2,860 mm (112.6 in)|
|Length||4,780 mm (188.2 in)|
|Width||1,760 mm (69.3 in)|
|Height||1,410 mm (55.5 in)|
|Curb weight||1,251–1,292 kg (2,759–2,848 lb)|
The NSU Ro 80 was a technologically advanced large sedan-type automobile produced by the West German firm of NSU from 1967 until 1977. Most notable was the powertrain; a 113 bhp (84 kW; 115 PS), 995 cc twin-rotor Wankel engine driving the front wheels through a semi-automatic transmission employing an innovative vacuum system. It was voted Car of the Year for 1968 by European motoring writers.
Other technological features of the Ro80, aside from the powertrain, were the four wheel ATE Dunlop disc brakes, which for some time were generally only featured on expensive sports or luxury saloon cars. The front brakes were mounted inboard, reducing the unsprung weight. The suspension was independent on all four wheels, with MacPherson struts at the front and semi-trailing arm suspension at the rear, both of which are space-saving designs commonly used today. Power assisted ZF rack and pinion steering was used, again foreshadowing more recent designs.
The car featured an automatic clutch which was commonly described as a three-speed semi-automatic gearbox: there was no clutch pedal, but instead, on top of the gearknob, an electric switch that operated a vacuum system which disengaged the clutch. The gear lever itself then could be moved through a standard 'H pattern' gate.
The styling, by Claus Luthe who was head of design at NSU and later BMW, was considered very modern at the time and still holds up well; the Ro 80 has been part of many gallery exhibits of modern industrial design. The large glass area foreshadowed 1970s designs such as Citroën's. The shape was also slippery, with a drag coefficient of 0.355 (very good for the era). This allowed for a top speed of 112 mph (180 km/h). Indeed, comparisons have been drawn between the design of the Ro80 and the aerodynamic 1982 Audi 100 - ironically built in the same factory some 15 years later.
Interior trim combined cloth covered seats with PVC headlining and a carpeted floor. Leather seats were a factory option, although rarely specified
The company's limited resources focused on improving the reliability of the rotary engine, with much attention given to the material used for the rotor tips that sealed the combustion chambers. A feature of the engine was its willingness to rev quickly and quietly to damagingly high engine speeds, but it was precisely at these high speeds that damage to key engine components occurred: all Ro80s came with a rev counter, but cars produced after 1971 also came with an "acoustical signal" that warned the driver when the engine was rotating too fast.
In most respect the Ro80 changed very little during its ten years in production. From September 1969 the rectangular headlights were replaced with twin halogen units, and air extractor vents appeared on the C-pillar behind the doors. In August 1970 a slightly reshaped plastic grill replaced the metal grill of the early cars, and a minimal facelift in May 1975 saw the final cars getting enlarged rear lights and rubber inserts in the bumpers which increased the car's overall length by 15 mm to 4795 mm.
Unfortunately for NSU, the car developed an early reputation for unreliability, from which it would never escape. The Ro80 engine in particular suffered from construction faults, among many other problems, and some early cars required a rebuilt engine before 30,000 miles (50,000 km), with problems visible as early as 24,000 kilometres (15,000 miles). The three-piece rotor tip seals were made out of the same material. The design fault caused the center section to have higher abrasion at cold starts than the corner pieces and the tip seals could push together, allowing the gas to blow past. With a changed tip seal design this was temporarily solved and with a tip seal center piece made of Ferrotic, the problem was entirely resolved. The fact that the rotary engine design was inherently thirsty (typically 13-16 l/100 km) and a poor understanding of the Wankel engine by dealers and mechanics did not help this situation. By the 1970 model year, most of the reliabity issues had been resolved, but a necessarily generous warranty policy and damage to the car's reputation had undermined NSU's financial situation irreparably. NSU was acquired by Volkswagen in 1969, and merged with Auto Union to create the modern day Audi company as it is known today.
Second hand Ro80s were virtually worthless in the 1970s due to the well-publicised engine problems, and a common "cure" for an ailing rotary engine was simply to swap it for a Ford V4 "Essex" engine (as found in Mk1 Transits) since it was one of the few engines compact enough to fit in the Ro80's engine bay. Thus in an ironic twist, one of the smoothest engines in the world was replaced by one of the roughest.
The NSU's unpopularity caused by the above problems means that surviving examples are very rare, and are now considered highly prized classic cars with values to match, particularly thanks to Mazda's perseverance with rotary design, the tip seal problem has been all but eradicated.
Series production began in October 1967: the last examples came off the production line in April 1977.
During 1968, the first full year of production, 5,986 cars were produced, increasing to 7,811 in 1969 and falling slightly to 7,200 in 1970. After this output declined, to about 3,000 - 4,000 per year for the next three years. The relative thirst of the rotary engine told against the car after the savage fuel price rises accompanying the oil crisis of 1973, and between 1974 and 1976 annual production came in well below 2,000 units. In total 37,398 Ro80s were produced during the ten-year production run.
- Citroën GS Birotor
- NSU Spider: the Spider had been the world's first Wankel engined production car
- Mazda Cosmo
- "Autocar Road Test NSU Ro80 1,990 c.c. (nominal): German five-seater touring car with twin-rotor Wankel engine and front-sheel-drive. Rather poor petrol and oil consumption. Superb road-holding and stability. Power steering light with excellent "feel". Fine visibility and well-placed controls. Selective automatic transmission gives three wide performance ranges. Very advanced and pleasant car to drive.". Autocar. 128. (nbr 3755): 11–16. February 1968.
- Oswald, Werner (2001). Deutsche Autos 1945-1990, volume 4 (in German). Motorbuch Verlag. p. 403. ISBN 3-613-02131-5.
- "NSU". der-wankelmotor.de. Retrieved 2010-09-16. (German)
- "Die Gasdichtung des Wankelmotors". www.der-wankelmotor.de. Retrieved 2010-09-16. (German)
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