Opel traveled to the 1969 edition of the Frankfurt Motor Show to unveil a state-of-the-art concept car dubbed CD, a name that stood for Coupe Diplomat. Billed as merely a design study, the CD was the work of a team led by American designer Chuck Jordan, the same man who designed the Opel GT as well as a number of well-known American cars like the 1963 Buick Electra and the 1967 Cadillac Eldorado.
The CD featured a wedge-shaped body with a one-piece wraparound windshield that tilted forward in a Jetsons-like manner to provide access to the cabin. The body was designed using data gathered in a wind tunnel – a real novelty at the time – and the final product was crafted out of fiberglass in order to keep the coupe’s weight in check.
Inside, the CD boasted a futuristic function-over-form cockpit with an aircraft-inspired instrument cluster, a two-spoke steering wheel and unusually wide power-adjustable pedals. A center console mounted over the transmission tunnel housed the car’s climate control and radio functions in addition to a telephone. Interior designers put a big emphasis on comfort and the coupe’s passengers traveled on generously-sized leather-upholstered seats.
Power for the CD came from a 5.3-liter V8 engine sourced from the then-new Diplomat B. The engine sent 230 horsepower to the rear wheels via a three-speed push-button automatic transmission, though sources close to Opel have recently revealed the CD was not a functional concept.
The CD unexpectedly stole the Frankfurt show in 1969, leaving show-goers and journalists in awe. Equally stunned, Opel tentatively asked Italian coachbuilder Frua to build a less futuristic version of the car with a toned-down exterior design and a more realistic interior. Opel insisted that the coupe had to retain the concept’s lightweight fiberglass body and the Diplomat-sourced V8.
Frua built several prototypes for Opel but the project was ultimately canceled. Opel couldn’t build the CD in-house and it feared Frua’s relatively small workshop didn’t have the necessary production capacity to assemble even a low-volume car. Opel’s bean counters believed the automaker would lose money on the CD because it would be an expensive halo car that would appeal to a very small target audience, and GM executives in Detroit ultimate blocked the car on account that it could end up rivaling the Corvette.
The CD story didn’t stop there. Erich Bitter saw a huge potential in the coupe and formed his own company in 1971 in order to build a modified version of the Frua-designed prototype. Dubbed simply Bitter CD (pictured below), the coupe was underpinned by a modified version of the Diplomat’s platform and it was powered by the same 5.3-liter V8 that was found in the original CD concept. Bitter built 395 examples of the CD between 1973 and 1979.