The Bitter CD, a three-door hatchback coupe featuring a
Chevrolet V8 with a 327ci displacement, was built between 1973 and 1979. The CD was first shown in prototype form on 9 September 1969 at the
Frankfurt Auto Show, as the
Opel Coupé Diplomat ("CD") derived from the
sedan version. It was designed by
Charles M. "Chuck" Jordan (Opel's Design boss between 1967 and 1971 and later vice-president of
General Motors (GM)) and Opel designer Dick Ruzzin, with the assistance of George A. Gallion, David Holls, Herbert Killmer and Hideo Kodama, as well as Erhard Schnell (Director of the Opel Designstudios 3 for Advanced Design from 1964). The tail was inspired by an Erhard Schnell's proposal for the 1969
Opel Aero GT. Thanks to the positive reaction to the CD prototype, Opel considered developing a production model. The doors would adopt a conventional opening system and the bumper bar, windshield wipers and other parts would be derived from the Opel Diplomat in order to facilitate production and maintain costs.
Robert "Bob" Lutz, who was Opel's Head of Sales and Marketing at the time and was keen to produce the car, commissioned
Pietro Frua to advance the concept and produce two road-going prototypes. In 1971, it was David R. "Dave" Holls (Opel design boss since July 1971; previously assistant to Chuck Jordan) who encouraged Erich Bitter to build the Bitter CD. As a result, Bitter GmbH was formed in 1971 to market the CD. He chose to locate the company on a site in his home town of
Schwelm, Germany. However, because he did not have the necessary capital and other resources to set up his own production facilities, Bitter turned to
Baur GmbH in Stuttgart, as a proven independent small-scale manufacturer. He selected them based on their ability to produce high-quality prototypes and limited-production cars for other German manufacturers. Bitter based his original CD designs on those of Frua, before making alterations closer to production. The basic design changes to Frua's CD design vis-à-vis the 1969 Opel CD consisted of a truncated rear end, modified windshield and less chrome application. Dave Holls and Opel's design team supplemented the design with a small front spoiler, larger grille, higher bumper bars and by prolonging upwards the lower edge of the rear side windows across the
C-pillar to the rear hatch. Final prototype testing was conducted at the Opel Test Facility in Dudenhofen, in addition to load duration tests by Bitter at the Hydropulseur facility of Baur. The Baur team also engaged in significant development work, which included manufacturing a hard foam mockup. Their role then extended to manufacturing the CD body panels, assembling the shell, preparing interior as well as installing the Opel Diplomat's mechanicals. The Bitter CD was displayed, with great success, at the
1973 Frankfurt Motor Show, where Erich Bitter took 176 orders for his stylish new coupe. However, the
1973 oil crisis led to the cancellation of most orders. Despite this, production commenced later that same year at Baur GmbH. The target of 200 units a year was never realised, and Bitter sold 395 units in total. The purchase price in 1974 was
DM 58,400. ; Total production by year ==SC==