The Opel Senator is a full-size executive car (E-segment) produced by the German automaker Opel, two generations of which were sold in Europe from 1978 until 1993. A saloon, its first incarnation was also available with a fastback coupé body as the Opel Monza and Vauxhall Royale Coupé. The Senator was, for its entire existence, the flagship saloon model for both Opel and Vauxhall.
Through the international divisions of General Motors, it was also known in various markets as the Chevrolet Senator, Daewoo Imperial (in South Korea), Vauxhall Royale (until 1983) and Vauxhall Senator (which took the place of the Royale on Vauxhall models when the Opel brand was phased out from 1983). It was also sold as the Opel Kikinda in Yugoslavia, where it was produced under licence by IDA-Opel in Kikinda, Serbia, after which it was named.
The original Senator was a de facto replacement for Opel's KAD cars (the Opel Kapitän, Admiral and Diplomat), which competed in the F-segment (full-size luxury) in which the KAD cars had sold poorly. Sister company Vauxhall had already abandoned the segment with the demise of its Cresta/Viscount models some years earlier, leaving the Ventora model (a luxury derivative of the FE Victor/VX4) as its flagship offering but this was axed in 1976 with no direct replacement.
The Senator shared its platform with the smaller Opel Rekord, the latter being lengthened to make the Senator. The second generation of that car, from 1987, shared its base with the Rekord's Opel Omega successor, which was again lengthened to produce the Senator.
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Senator A (1978–1986)
The Senator A was last part of a joint model programme executed by GM in the 1970s to develop a common series of vehicle platforms for both its European brands (and also for the Holden brand in Australia). The first two product families of this strategy – the T-Car (Kadett C/Chevette) and the U-Car (Ascona B/Manta B/Cavalier) had already been released. The V-Car (or V78) platform would simultaneously provide the next-generation Opel Rekord, a replacement for the Vauxhall FE Victor, and a 'stretch' version to replace the unsuccessful 'KAD' cars, and act as a flagship for both Opel and Vauxhall.
The Senator therefore emerged as a long wheelbase version of the Opel Rekord E, complemented by a three-door fastback coupé version on the same platform called the Opel Monza, which was intended as a successor for the Opel Commodore coupé.
Names and markets
The Senator A and Monza were initially sold in the United Kingdom as the Vauxhall Royale (and Vauxhall Royale Coupé). Unlike other members of the joint Opel/Vauxhall model programme of the period, the Royale was simply a badge engineered version of the Senator with only detail differences from its Opel sister.
Following the merger of the UK Opel and Vauxhall dealer networks in 1982, the Opel marque was repositioned as a performance-luxury brand, and the Vauxhall Royale models were dropped in favour of the Opel Senator/Monza, coinciding with the "A2" mid-cycle facelift. This policy was reversed in late 1984, with the Senator reverting to Vauxhall branding for the 1985 model year, but the Monza remained on sale as an Opel until its discontinuation at the end of 1987.
The vehicle was also available in South Africa as the Chevrolet Senator until 1982, when it was rebadged as an Opel. It filled the gap left by the Holden based Chevrolet Caprice Classic, which was sold there from 1975 to 1978. The Chevrolet Senator was fitted with a locally built version of Chevrolet's 250 inline-six (4,093 cc), with . The post-1982 South African Opel Senator received Australian-built, six-cylinder engines. In Serbia, the locally assembled Senator received the 2.5-litre six and was badged the "Opel Kikinda". With it was very close to the now irrelevant 2.8 and its , and the 2.8S was discontinued in 1982.
Facelift (A2)
The original Senator and Monza were facelifted in November 1982, although the Senator "A2" (as it is usually called) only went on sale in March 1983. In the United Kingdom, it was initially sold only as an Opel, before being rebadged as a Vauxhall in 1984. The A2 Monza was only sold as an Opel.
The facelifted car looked similar to its predecessor, with relatively minor changes: smoothed-off headlights increased in size, and chrome parts were changed to a matt black or colour coded finish. The car was much more slippery, with drag resistance down (from 0.45 to 0.36 <math>\scriptstyle C_\mathrm x\,</math>). The top of the range 3.0E received upgraded Bosch LE-Jetronic fuel injection.
Interiors were improved with an altered dashboard and the new instrument pack with larger dials used in the Rekord E2, and engines changed. Now, the fuel-injected straight-four two-liter cam-in-head unit from the Rekord E2 was available, although with little fanfare; this and the 2.5 essentially replaced the Commodore which was itself quietly retired in 1982. Power of the 2.0 was soon increased to . In March 1983 a 2.3-litre turbodiesel (shared with the Rekord) became available, and a few months later ABS-brakes (hitherto only available for the Senator CD) became an available option across the entire Senator/Monza range. the four-cylinder models were never sold in Vauxhall form in the United Kingdom.
<gallery widths="200px" heights="130px">
File:Opel Senator front 20080303.jpg|Opel Senator A2 (1982–1986)
File:Opel senator 1 h sst.jpg|Opel Senator A2 (rear)
File:Vauxhall Senator with war poppies registered August 1985 2968cc.JPG|Vauxhall Senator (A2)
</gallery>
Shortly thereafter, in November 1984, a supercharged version (Comprex) was shown – at the time, the only production car in the world to use this technique. Going on sale in 1985, this rare experimental version (1,000 units planned) was officially built by Irmscher rather than Opel. The Comprex offered and a top speed, and acceleration figures showed a twelve percent improvement over the turbodiesel. Like the other Rekord and Senator diesels, it had a pronounced bulge in the bonnet. The Comprex offered marginally higher power than the turbodiesel, but more importantly, 90 percent of the maximum torque was available from 1300 rpm. The system uses a viscous coupling to distribute power with a 60/40 rearward bias, to improve traction while maintaining the Senator's handling characteristics. These were used by British Forces Germany under the BRIXMIS (British Commanders' in Chief Mission to the Soviet Forces in Germany) operations for the collection of technical intelligence. The same kit was also used by Bitter Cars for a four-wheel-drive version of their SC coupé, beginning in the end of 1981. The main feature of the new engine was a "Dual Ram" system, increasing torque at low engine speeds by means of a redirected air flow system which engages at 4,000 rpm. The engine in police service was capable of a speed of up to , although the bonnet was prone to rippling at such high speeds. For 1990 the 2.5 L was replaced by a 2.6 L Dual Ram. The twelve-valve, 3-litre version was deleted from the range in 1992. CD versions of the 2.6 L (UK market only), and a 24 valve 3.0 L were available up to the model's withdrawal in 1993.
With the second generation Omega presented at the end of 1993 and available for sale from March 1994, Following the announcement of the discontinuation of the Senator, the government of the United Kingdom would order a final batch of around 200 Vauxhall Senators in 1993 for diplomatic and policing use prior to moving over to the Vauxhall Omega, and on some police forces they entered service a year or more later with M plate registrations.