Carefully leaked in 1986, and officially announced at Frankfurt in 1987, BMW's little Z1 roadster was a brilliant high-tech rear-wheel-drive two-seater roadster. But, due partly to its unusual construction and partly to its limited market, it would remain rare and expensive, even on home ground.
But the Z1 was a vital product for BMW nevertheless; its value as a show-car was necessarily short-lived, but its appearance allowed BMW to showcase its then latest offshoot, BMW Technik.
An independent "think-tank" of some 100 styling and technical experts, BMW Technik had a brief to investigate future materials and techniques without worrying about production constraints. Its main objective in this, its first project, was to study ways of shortening the gestation period for new models.
That the project turned into a car at all, and a sports-car in particular, BMW claimed was due in no small part to the collective enthusiasm of the team. And that the car was "sold" to the BMW board and made it to production showed the extra flexibility which the new department offered.
As a vehicle for new technologies, the Z1 excelled; it had an all-plastic body, novel rear suspension, and those innovative doors which could be left open while in motion. Even the German TUV agreed that this was safe, and BMW started production confident that other countries would take the same view.
The slim doors dropped down into deep side-sills which give the chassis immense rigidity and safety from side impacts.
Yet there had been no compromise over comfort and practicality; careful attention to aerodynamics had resulted in minimal draughts in the cockpit, the smooth spoiler-free styling concealed impact-absorbing bumpers beneath higly flexible panels, the screen surround formed a roll-bar and there is a small boot in the stubby tail.
Power came from the well-proven 170 bhp straight six engine and five-speed box from the 325i, but set well back in the galvanised steel chassis and solidly connected to the differential through a thick alloy tube. This "spine" had only three body mounts (two front, one rear), and gave the stubby car a 49:51 front: rear weight-balance. The pressed steel parts which made up the car's frame are further strengthened by bonding in a compoosite floorpan, and even the galvanising process is claimed to add rigidity.
All the running gear is attached to this frame, so that the skin is completely stress-free. A new paint process was required to handle the three different materials used for the body; injection-molded high-impact plastics for the sides and wings, elastic material for the "bumpers", and foam-cored fibre composites for bonnet, boot and roof cover. All these panels can be removed in 30 minutes. These methods, says BMW, save some 100kg over conventional construction to achieve the same rigidity.
At the front, a wide-track variation on the 3-series strut was employed, but the rear wheels were located by a new and very accurate system known as the "Z axle" . Two lateral arms guided the wheel vertically, while a massive trailing link curved round the tire from a pivot in line with the hub. Camber changes and bump-steer were eliminated, but there was a degree of passive steering; toe-out was introduced to give crisper turn-in, changing to toe-in as lateral forces rose, minimising the risk of throttle-off oversteer. Eccentric bushes allowed for fine adjustment should anyone have wanted to take to the track.
BMW claimed that the Z1 could generate up to 1G laterally on its 16in 225/45 tires, and certainly several road tests carried out at the cars launch attested to the fact that the little car had exceptional roadholding. What is more, BMW achieved a superb degree of high-speed damping without making the car hard over slower abrasions. The Z1 dealt firmly with sudden brows or mid-corner bumps, keeping the wheels in touch with the ground and generally feeling as lively as a go-kart, but of course much more comfortable.
Though the 3-series power steering was not especially fast, the sheer sharpness of the chassis gave the Z1 a delightful feeling of agility; it was completely stable under rapid cornering, and if the bend proved to be sharper than expected, a further twitch of the wheel instantly gave a tighter turn. Stylish seats would keep you anchored, and the cabin layout was well up to BMW standards, with plain round dials under a motorcycle-style cowl. There was only one real flaw inside - a complete lack of storage, although a panel could be removed to give access to the boot and even to carry skis. Stopping power came from the 325i but with larger rear discs, and ABS was standard.
Driving With The Doors Down
Driving with the doors down would feel novel to anyone who had not driven a pre-war sports-car, but it became fairly windy at 40-plus mph; better to flick the handle and watch the lightweight panel glide up (it could be done manually should motor or battery fail). Buffeting from behind, the perennial sports-car bugbear, had been virtually eliminated, helped by free-standing mirrors on the A-pillars, and rear axle lift was substantially reduced by channelling air up under the tail around a wing-shaped exhaust silencer. A separate motor on the chassis operated the window through an ingenious L-shaped link.
Like the 3-series convertible, the hood was concealed by a smooth cover when down, and it flipped up with one hand. There were no hooks or poppers - when tensioned, it pressed down on the cover behind the seats and locked into the screen rail. The rail itself was unusual in standing proud of the top of the screen; this increased its strength in a roll-over, and made a useful grab-handle for getting in and out. Top up, visibility was still good through the glass rear light, and wind noises were low.
High power headlights, a pop-up roll bar and acrylic paint that flexed with the plastic panels were also pioneered by BMW on the Z1. Under its synthetic skin, which BMW said could be swapped for another color in 40 minutes (owners claim it actually takes two days), the stiffening of the undertray and multilink ‘Z’ rear axle made the Z1 a sure-footed driver’s car.
In its design and execution, the little Z1 was a gem: its driving qualities were superb; its unique doors offered a novel driving experience. For BMW it proved several new ideas, not least that the new Technik department would be a real asset. Such a vehicle could not be adapted to automated assembly; instead it was hand-built at a rate of about ten a day in the small area in the main BMW plant vacated by the old pilot line, now removed to a new Research and Engineering Centre. Only some 1500 cars were built in 1989, despite orders exceeding 4000.
Limited Production Makes For A Highly Sought Classic
The vast majority of 8000 Z1's manufactured (6,443) were sold in BMW's native German market. The country to receive the second-greatest number of Z1s, Italy, received less than 7% of the total sold domestically. None were initially sold in North America, although it is uncertain whether examples were independently imported since the car's launch. More than half of all Z1s (specifically, 4,091) were produced for the 1990 model year. Seventy-eight Z1s were reportedly used as test mules, although most were later sold without a warranty and, presumably, at a lower price.
The Z1 was available in six exterior colors and four interior colors, although the vast majority (6,177) were red, black, or green with a dark grey interior. Light yellow exterior (fun-gelb
in German or fun yellow
in English; 133 examples made) or red interior (38 examples made) are the rarest Z1 colors. The colors swimming pool blue
were reserved for the car's designers, Bez and Lagaay.
Reportedly, some 1,101 Z1s were delivered without a factory radio installed. In these vehicles, BMWS AG installed an aftermarket SONY radio in its place. None of the Z1s were sold with air conditioning. The vehicle's dashboard is very small and there was no room for both heat and cooling units. Some Z1's were converted using BMW E30 parts to have air conditioning, but reportedly the heater elements had to be removed. BMW Z1s officially imported to France for sale there have yellow headlights instead of the clear ones found elsewhere.