Bitter CD: the Opel Diplomat coupé that reached production

The Bitter CD is a three-door hatchback coupé built in Germany from 1973 to 1979 by Erich Bitter Automobil GmbH. It grew out of a 1969 Opel design study for a coupé version of the Diplomat, used Opel Diplomat mechanicals and a 230 PS Chevrolet V8, and was assembled in small series by Karosserie Baur in Stuttgart.

Bitter CD at a glance

There is no separate English or German Wikipedia article on the CD: this page is based on the CD section of the English article on the Bitter marque, so it rests on one source.

History of the Bitter CD

A coupé for the Opel Diplomat

The car began as a design study, not as a Bitter. On 9 September 1969 Opel showed a prototype at the Frankfurt Auto Show called the Opel Coupé Diplomat, or CD, derived from the Diplomat saloon. It was designed by Charles M. “Chuck” Jordan, Opel’s design boss from 1967 to 1971 and later a vice-president of General Motors, together with the Opel designer Dick Ruzzin and with the assistance of George A. Gallion, David Holls, Herbert Killmer, Hideo Kodama and Erhard Schnell. The tail was inspired by Schnell’s proposal for the 1969 Opel Aero GT.

From study to production car

The reaction to the prototype was positive enough for Opel to consider a production model: the doors were to open conventionally, and the bumpers, windscreen wipers and other parts would come from the Diplomat to keep costs down. Robert “Bob” Lutz, then Opel’s head of sales and marketing, commissioned Pietro Frua to develop the concept and build two road-going prototypes. In 1971 David Holls, by then Opel’s design boss, encouraged Erich Bitter to put the car into production. Bitter GmbH was formed in 1971 and set up on a one-acre site in Bitter’s home town of Schwelm.

Bodies from Stuttgart

Bitter had neither the capital nor the facilities for his own factory, so he turned to Baur GmbH in Stuttgart, an independent manufacturer already known for high-quality prototypes and limited-production cars. Bitter based his first CD designs on Frua’s and then altered them closer to production: a truncated rear end, a modified windscreen and less chrome. Holls and the Opel design team added a small front spoiler, a larger grille, higher bumpers and carried the lower edge of the rear side windows up across the C-pillar to the hatch. Prototypes were tested at Opel’s facility in Dudenhofen and at Baur’s Hydropulseur rig. Baur built a hard foam mock-up, made the body panels, assembled the shell, prepared the interior and installed the Diplomat’s mechanicals.

Sales and the oil crisis

The CD was presented at the 1973 Frankfurt Motor Show, where Erich Bitter took 176 orders. The oil crisis that year cancelled most of them, but production began at Baur later in 1973 all the same. The planned 200 cars a year were never achieved: Bitter sold 395 examples in total, at DM 58,400 in 1974.

Design and features

• Opel underneath: Diplomat mechanicals kept development and parts costs down.
• American power: a Chevrolet 327 V8 of 230 PS gave the coupé performance to match its price.
• Italian development: Frua built the two running prototypes that turned the Opel study into a road car.
• Coachbuilt body: Baur in Stuttgart made the panels and assembled each car by hand.
• Low volume: 395 cars in six years, against an annual target of 200.

Bitter CD versions

• Opel Coupé Diplomat (1969): the show prototype by the Opel design team, with the tail of the Aero GT proposal.
• Frua prototypes (1970–1971): two road-going cars built by Pietro Frua for Opel.
• Bitter CD (1973–1979): the production coupé with Diplomat running gear and a Baur body.

The CD was followed by the Bitter SC, based on the Opel Senator. More cars are in the Bitter collection.

Video: Opel Bitter CD: The Story

Video on YouTube.

Sources

• Bitter Automotive, English Wikipedia: design, development, production, price