1987 BMW Z1

The BMW Z1 first zipped into the public consciousness when it was revealed at the 1987 Frankfurt Motorshow. Production followed in 1989 and continued until 1991. Designed in-house by BMW designer Harm Lagaay, the distinctive two-seat, rear-wheel drive roadster has now become a modern classic.

When the BMW Z1 concept was released, it sent a shock wave through a stagnant small sports car market and soon received thousands of pre-orders. By the time the Z1 reached production, however, much of the initial interest had dissipated. Around 8,000 cars were sold in total, the majority of which remained in Germany.

Construction was sophisticated, with a steel monocoque and clip-on bodywork panels. Further chassis strength was provided by a rigid torque tube, bonded plastic underbody and an integrated roll-bar which surrounded the windscreen. The distinctive gap between the rear bumper and boot is more than just a styling quirk: it works with the exhaust silencer to form a simple rear diffuser. These innovations came at a price – £36,925 when the car was launched in Britain.

The BMW Z1 was only offered with a normally-aspirated 2.5-litre straight-six and five-speed manual gearbox, as used in the BMW 3 Series E30 325i. Though fuel injection was fitted, the engine is relatively simple for the period. It features a single overhead cam and two valves per cylinder, producing 170 bhp and 164 lb-ft of torque.

Those unique drop-down doors define the experience of driving a BMW Z1. With so much of the car open to the elements, drivers are treated to a sensation of speed rarely found in modern classics. Acceleration is unhurried but enthusiastically delivered, the Z1 producing peak power at 6,800 rpm. Grip levels are high, thanks to 225 mm width tyres, with neutral and accessible handling.

The BMW Z1 shared its engine, transmission and MacPherson strut front suspension with the more numerous 3 Series E30 325i. Replacements for these parts are widely available through specialists and breakers. Model specific parts pose more of a challenge. Some items are readily available through BMW Group Classic, such as the steering wheel and alloy wheels. Others items, including the dampers, steering rack and interior upholstery, are difficult or impossible to procure.

Bodywork panels are fibreglass or plastic and clip to the chassis, making them easy to replace. Cracks and scratches, however, are difficult to rectify. The doors are operated by a toothed belt and should operate smoothly, taking five seconds to drop and slightly longer to rise. Exterior lights can cloud up and the boot become damp, both the result of perished rubber seals. The monocoque was fully galvanised from new and further protected from corrosion by the bonded plastic underbody.

Choosing a Z1 is a simple exercise. With no facelifts, major updates or different drivetrain options, buyers are left to discriminate on condition and colour alone. Red cars are the most common, and yellow the rarest. Conversely, red is the least common upholstery colour.

Alpina, an independent tuning company closely affiliated with BMW, was authorised to produce small numbers of modified Z1 known as the Roadster Limited Edition. These cars featured a 2.7-litre straight-six with 200 bhp, shorter front springs and a number of visual changes, including 17-inch Alpina wheels. These cars, of which 66 were constructed, are now highly valued and command a hefty premium over the standard car.

BMW followed the Z1 with a more conventional, series production roadster called the Z3. A Z3 coupe, with distinctive breadvan bodywork, was also offered. Plenty of alternative two-seat roadsters were launched during the 1990s. Keen drivers might choose the Renault Sport Spider or Lotus Elise, while the Mazda MX-5 and Lotus Elan M100 provide a more conventional roadster experience.