The Vauxhall Calibra – Vauxhall’s Aerodynamic Obsession

At the start of the 1990s a steady stream of Japanese coupes reached the UK car market. Exciting new cars like the Nissan 200sx, Toyota Celica and Honda Prelude all vyed for attention.

Both Vauxhall and Ford had managed to keep selling older cars that were way past their best. The Manta and Capri were old hat. New models from Japan promised reliability, more modern design and technology at a competitive price.

Vauxhall had a replacement planned, but it had a fight on its hands too.

Pictures courtesy of Absolute Classic Cars who sold this wonderful example in 4×4 Turbo Spec.

Vauxhall Calibra Design

The project was led by American Wayne Cherry who worked for Vauxhall before heading up car design at Opel. A surprise visit from the General Motors President in was an opportunity to gain support for the new project. In response, Cherry gave Erhard Schnell the task of styling the Calibra which was completed in just a week.

“A new, modern design language. I had complete freedom with the styling”

Erhard Schnell – Vauxhall Calibra Designer

By July 1987 the project was given the go ahead and an official project code “P-2670”.

Project P-2670 Starts

Cherry was already an advocate of aerodynamics and in Hans-Joachim Emmelmann he found another. Emmelmann’s job was to oversea the aerodynamics as the car was being made ready for production.

With Wayne Cherry in charge, aerodynamic excellence was a certainty. His previous work on the “Dropsnoot” and SRV concept car focused on the benefits of aerodynamics.

Hans-Joachim Emmelmann was another advocate for aerodynamics on the engineering side of the project. The head designer of the project was Erhard Schnell, renown for his work on the Opel GT.

What better project than a slippery coupe to demonstrate this aero obsession to the world?

Vauxhall/Opel Aerodynamic pioneers

In most companies the aerodynamic work was done early on in the project along with styling. Scale models were used to get a CD (Drag Coefficient) figure and if acceptable, production would start. As the model developed, this figure would decline as trim, bumpers and other items were added to the production version.

This structure was changed so aerodynamics were revisited at each stage of the project until the final detail optimisation stages. This meant constant testing in the DNW wind tunnels in Stuttgart and Amsterdam.

Vauxhall Calibra – Aerodynamics

The proposed car used a shortened version of the GM2900 platform. For simplicity this was changed to the standard platform which had the additional benefit of seating four in comfort. Schnell was insistent on using frameless doors, slim headlights, indicators and fog lamps -which improved aero efficiency further.

A scale model of the Calibra started with a CD of 0.33. Emmelmann quickly found issues around the front bumper and panel gaps which could be improved.

Extracts below from the journal “The Aerodynamic Development of the Opel Calibra”

  • Front spoiler
    “By moving the sides of the spoiler 60mm outboard, to cover more of the front wheels, a CD reduction of .006 was obtained”
  • Side skirts
    “The lowering (of the side skirts) was realised by the addition of plastic rocker mouldings”
  • Underbody optimisation
    “Only one aerodynamic feature remains on the underbody. The plastic tank spoiler, between the fuel tank and the rear bumper incurred a reduction of 0.003”
  • Anti contamination lips
    “The lips integrated into the rubber windshield mouldingserve the purpose of directing dirty water from the windshield up the A pillar and onto the roof…
    “A lip in the side mirrors guided dirty water away from the side windows and mirror”

The tapered rear quarter window of the Calibra increased aerodynamic efficiency by 50% alone. Flat surfacing around the wheel arches completed the bodywork changes. The first Calibra had an incredible CD 0.26 the lowest of any mass produced car at the time.

Vauxhall Calibra – Launch & Production

The Calibra was launched at the Frankfurt motor show. The Calibra even overshadowed the launch of BMWs new 850i. In the UK the Calibra was launched with much fanfare and a selection of great TV adverts:

The Calibra was effectively a MKIII Cavalier underneath the refined bodywork. This meant it would never be a dynamic wunderkind, so the new car would rely on style more than most.

Thankfully the famous Vauxhall “Red Top” C20LET engine was fitted, to accompany the show with some go. This engine would later be turbocharged and combined with a four wheel drive system. In typical nineties style, this meant some excellent badges reading “Turbo” and “4×4”.

The interior was from the MKIII Cavalier which was practical and hard wearing. White dials, a boost gauge and a very early trip computer were some of the interior highlights.

The MKIII Cavalier platform meant a big practical boot and comfortable seating for four.

Vauxhall Calibra – Performance

While the exotic styling belied it’s Cavalier roots, the Calibra’s handling could not. Against the Nissan 200sx, Toyota Celica and Honda Prelude the Calibra was outmatched dynamically. The Honda (Which journalist LJK Setright loved) and Nissan would remain memorable cars to drive years later.

The Calibra wasn’t going to win awards for handling, but compared well in style, value and equipment. The Calibra V6 was replaced with the turbocharged C20LET engine and 4×4 running gear. The most potent version, with 204 bhp it reached 60 mph in 6.4 seconds and a top speed of 152mph. Enough to keep the legendary 1992 Escort Cosworth honest (in a straight line at least).

Against the slightly less exotic opposition in the coupe market, the Calibra looked like a good option. Stylish and quick it competed admirably against the VW Corrado, Audi Coupe, Fiat Coupe, Rover Tomcat and later the Ford Probe.

Calibra Modifications

Sadly like a lot of nineties performance cars, the Calibra suffered at the hands of the UK car modification scene. The C20 engine was cheap and easy to upgrade. Unfortunately modifications to the bodywork ruined the carefully crafted aerodynamics.

The UK scrappage scheme encouraged many owners to trade in their Calibra to get credit on new cars. 186 Calibra’s met their end this way. The engine was often removed and used in Westfields and other kit cars making the car even rarer.

A number of special editions (the SE series cars) were launched based on the entry-level car but with more equipment. The end of production in July 1997 was marked by a final special edition, the SE9. In total 40,460 Calibras were sold in the UK. The next Vauxhall 4 seater coupe was the Monaro in 2004 (co-incidentally with a far more significant drag coefficient of 0.31).

The Calibra was a statement of intent from Vauxhall and many of the techniques pioneered on the Calibra soon became commonplace.

Vauxhall Calibra Turbo 4×4
Engine:C20LET 1998cc i4
Power:204 bhp
0-60:6.4 Seconds
Top Speed:152 mph
Price when new:£17,250

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