Fresh Heir. BMW has redefined the roadster; it’s the superb 1988 BMW Z1 by Georg Kacher. The Z1 is one of the most fascinating cars of the ’80s… When early prototypes of BMW’s Z1 roadster were thrown around the skid-pan at maximum effort, an unexpected problem arose. After 10 or 15 minutes at the limit, the pistons started to jam because the lubrication system could not function properly, so high were the levels of lateral acceleration. And now that I’ve spent time in the car. I think I know how the engine felt I’m not sure I like the idea that the Bavarian engineers have raised the challenge of mastering a car to a level I can no longer reach.
The grip is staggering, and unless you do something very, very silly, the Z1 will iron out your mistakes even before you notice you’ve made them. We all suspected that, one day, such a production car would be produced, it’s just that I did not expect it to be a BMW.
The Z in Z1 stands for Zukuntl, German for ‘future’. ‘Looking into the future is what Technik GmbH is all about.’ says the senior project manager Dr Klaus Faust. ‘Alter all. the Technik division is the company’s advanced design and engineering arm which is working on alternative, and often avant-garde, solutions.’
Z1 is the first project of this in-house brain factory, founded three-and-a-half years ago as a technology-oriented counterpart to the product-oriented Motorsport department. Technik has now completed more man 140 Z-programmes, among them the steering wheel and finned alloy wheels of the BMW M5 E34. The team around Klaus Faust, chief engineer Rudolf Muller and the charismatic senior designer Harm Lagaay has evolved into an integral part of the BMW R&D division.
The Z1 is the brainchild of Dr Ulrich Bez, who left Porsche in 1982 to join BMW, but who, on October 1 1988, returned to Stuttgart where he was appointed chief engineer. His departure has hurt, but everybody at BMW understood that he was accepting a once in a lifetime opportunity. So far, the Bavarians have not found a replacement, and perhaps the cadre does not even need a new father figure because its democratic structure is based on teamwork rather than individual effort. When it produced its first public statement. Technik toyed only briefly with alternative vehicle concepts (among them were an off-roader and a luxury coupe) before it decided to develop a radical variation of the traditional roadster theme.
’It seemed the right thing for a company which has produced such classics as the 328, 503 and 507.’ Faust reminisces. ‘We agreed to develop an innovative and unusual car that linked the past to the future. The board liked it so much that they decided to put it on display at the 1987 Frankfurt Show, and from then on, Z1 assumed a natural energy which made it almost impossible for BMW not to put it into production.’
The Z1’s development time – just over three years – is incredibly short for a production model: some companies take longer to realise a facelift. In the course of gestation, the BMW engineers conceived a new shape, new rear suspension, new transaxle driveline and a totally new body concept featuring sliding doors and pvc panels. No. this is not just a plastic-bodied 325i. Look, for instance, at the clever CAD chassis, made by Baur coachbuilding in Stuttgart. This steel skeleton is the backbone of the two-seater, and it’s zinc-dipped for optimum corrosion resistance, instead of using a metal floorpan. BMW Z1 uses a synthetic underside which is light, stiff and smooth. This sandwich bottom, which is glued and bolted to the metal carcass, incorporates several high-stress areas which accommodate the seats and suspension elements.
Like the defunct Pontiac Fiero, this BMW is driveable without any of the 13 clip-on body panels being fixed in place. The monocoque alone is responsible for the structural integrity of this 2750lb (Fiero V6 is 2785lb) two-seater, which is bolted and glued together on the company’s former pilot assembly line in Munich.
Adding the skin – or removing it – is a 30minute job. BMW uses three different synthetics. The softest plastic is reserved for the fully integrated bumper sections which will digest impacts of up to 2.5mph. The doors, the wings and the rocker panels are made of General Electric’s Xenoy which is a little stronger, but still sufficiently elastic to cope with careless knees and parking fight nudges. A comparatively stiff compound material was selected for the bonnet, bootlid and folding top cover. Although all three grades of pvc can be sprayed with the same type of solid or metallic top coat, the viscosity of the clear lacquer varies according to the flexibility of the surface.
The entire impact-absorbing bumper system is made of partly loam-filled reinforced fibres. The doors, on the other hand, consist of a lightweight thermoplastic. Says chief designer Lagaay, ‘The fully street-legal sliding doors are a key styling element of Z1.
Without them, the car would lose a lot of its fascination’ At the push of the exterior lock button, or after pulling an inside lever, the door and window will disappear into the fat sill within five seconds. With the door up, you can wind down the window at pleasure, but as soon as the gate drops, the glass pane will also recede automatically. Both elements are power-operated by two electric motors and one flexible toothed belt. Since the actual winding mechanism is attached to the body, the door remains completely rattle-free in all positions. In the case of an accident or electrical failure, the power drive can be disengaged so that you can push the door down manually. But what happens in a high-speed side impact smash? According to BMW’s Gunter Klusmeyer, the sturdy sills will, in this case, absorb most of the impact energy. ‘And if the door itself has been destroyed, the driver can still escape through the roof.’
Since the rag-top Z1 has been a regular visitor to the BMW wind tunnel, its drag coefficient with the top up is an above- average – for a convertible 0 36. Fold the roof back, and this figure drops seven points to 0.43. Among the key drag cutting elements are the very low front end, the steeply raked windscreen, the virtually flush floorpan, the lip incorporated in the bootlid and the streamlined, wing-shaped transverse exhaust system which splits the underbody air flow to reduce rear axle lift. BMW claims to have shaped the windscreen, the A-pillars, the door mirrors and the car’s tail to minimise turbulence and direct the air past, rather than into, the occupants’ faces. But this achievement seems to be of a more theoretical nature. The first test drive showed that Z1 is as bad a whirlpool as any other open-top car, and there is no doubt that this cross-flow effect is further enhanced as soon as you drop the doors.
Z1 has already yielded several patents for us.’ says a proud Harm Lagaay. ‘They include the new high-intensity headlamp system, the Integrated roll-bar, the sliding door mechanism and the underbody air deflector.’ Asked what he likes best about the shape of Z1 the former Porsche and Ford designer answers instantly: ‘The proportions. We have redefined the roadster theme by cutting the overhangs and creating a virtually square, squat and very original car.’
Z1 can be had in four exterior colours: top red, fun yellow, original green and dream black. Swimming-pool blue and oh-so-orange are said to be reserved for the private vehicles of messieurs Lagaay and Bez. If you care for a personal opinion, let me tell you that the car looks only OK in red and black, while the deep metallic green – a shade you’d expect on a BMW motorbike – does enhance its futuristic shape. But the most appropriately exciting dress is, without a doubt, the pale creamy yellow which expresses the vehicle’s bizarre character so well. Predictably, however, a mere five percent of customers have ordered a yellow Z1.
The M20B25 2.5-litre six fitted to Zukunft One is an old friend we know from the 325i E30, but its position in the car is all-new. By placing it a full 10 inches further back, BMW’s engineers have created what they call a ‘front-mid-engined’ car.
This revised layout yields a perfect 49:51 front-rear weight distribution. Says a BMW engineer whose name I would rather not mention: ‘This solution will solve our traction problems once and for all. The first new car to feature a front-mid-engine layout will be the next-generation 3-series saloon (BMW E36), it does not presently have a transaxle driveline, but there is a good chance that the model following the new 3-series will.’
The Z1 suspension is equally interesting. While the front axle is virtually identical to the current 3-series (E30)’, the rear section of the chassis has been redesigned from scratch. It uses a multi-link rear suspension which BMW calls a centrally guided, spherical double wishbone axle. Any questions? Well ‘centrally guided’ means that the compact upper subframe, the transverse inks and the tie-rods are attached to the differential casing which is in turn connected to an aluminium tube that runs forward to the gearbox.
This tube, within which the propshaft spins, is rigidly bolted to the differential and gearbox, reducing the number of mountings needed for these hefty items. ‘Spherical’ describes the spatial distance between the tie rods and the suspension arms whose outer ends arc connected by coil springs. The shock absorbers are mounted to the wheel hubs which are part of the Z-shaped longitudinal links. There is also a relatively compact U-shaped anti-roll bar which keeps lateral body movements in check. Clever elastokinematics take care of anti-squat and anti-dive properties as well as of neutral handling characteristics and extraordinary cornering speeds. Thanks to the equal weight distribution, the low centre of gravity and the fat 225/45VR16 Pirelli P700 rubber, Z1 is on the skid-pan. capable of tolerating up to one g lateral acceleration.
Getting into and out of the Z1 is rather difficult for someone who has not been inside a gym since he left school There are basically three ways to saddle this horse. First, is the look- Here-Slraddie which may entail split trousers and a bruised right knee, but is popular with bystanders Number two is the Kacher-Flop which requires you to swing both legs into the car while airing the torso as you place one hand on the windscreen surround and the other behind the driver’s seat.
Number three is Sit-Down-First which makes it a shade difficult to pull in the lower extremities: but it can be done, and “d be a rich man if everyone who laughed had paid me a fiver. I suppose that time alone will teach you to become an expert Z1 rider, but it still breaks my heart that even the most careful feet will invariably foul the leather-trimmed sills So please take off those black brogues before you step into my canary-yellow collector’s item.
The first thing you notice inside this eye-catcher is how cramped it is. The cabin is as tight as a couple of middle-seats on Air Banana, and just about the only storage space is m the miniature boot which can also be reached through a flap behind the passenger seat. This token luggage receptacle holds an embarrassing 9.2cu ft, which is consistent with the maximum payload of 462lb. With the black canvas hood erect, the atmosphere is either cosy or claustrophobic, depending on your point of view. So, if the weatherman permits, fold down the roof – a quick and simple procedure thanks to the intelligent mechanism borrowed from the 325i E30 – and let in the air, the sky and all those envious glances. If you have dressed carefully and not eaten too much for lunch, you may now even lower the doors. This enables you to pat dogs at traffic lights or pick roadside flowers without getting out, but it also invites the world to scrutinise your pot-belly.
At least while it is still rare, the Z1 will be a more extravert car than a 25th anniversary Countach. It easily turns as many heads as a Great Dane in a pink feather boa, and it attracts more probing thumbs than the rubber whale tail on the very first Porsche Turbo.
The seats are actually very comfortable. They consist of body-colour plastic buckets I lined with foam-filled leather- trimmed cushions. While the adjustable backrest with its integrated head restraint is in charge of the upper part of Yours Truly, the lower half is wedged in by the tall centre tunnel on one side and by the even taller door sill on the other. There is a choice of two interior trims. One is cream leather and yellow high-tech fabric; outrageous-looking, but not very practical. The better alternative is a pot-pourri of charcoal hides with varying surface finishes.
All cars have the same standard specification. At the moment, no extras are available, but BMW is thinking of offering air-conditioning and perhaps a second set of body panels painted to the customer’s specification. That way, you would be able to drive a red car from Monday to Friday and a green car over the weekend. ‘Anything is possible,’ says Lagaay from behind his tinted gold-rimmed Ray Ban spectacles. ‘Just imagine bow easy it is to facelift this car or to change sections of the body.’
We have not yet started the engine because our eyes still rest on the Z1 cockpit which is so different from that of any other BMW. True, the heater and ventilation controls were taken from the E30 3-series, but the rest is new. Like the leather-trimmed steering wheel, whose spokes are styled like the roll-bar that houses the fragile sun visors; the palm-size door mirrors which are mounted halfway up the A-posts; or the motorbike-style instruments that include a raised rev counter, the only gauge with a bright red needle.
The ergonomics are first class, the visibility is good (with the top down), but the standard sound system is decidedly worse than the £75 kit fitted to the Swan National Maestro rental car that took me to the airport. The speakers are in the wrong position, the performance of the Sony receiver is weaker than alcohol-free beer, and the controls are so confusing that an inner voice keeps telling you rot to touch the bloody thing.
But who needs a radio when you can listen to a riveting live tailpipe concert? In Z1 form, the smooth M20 2.5-litre engine suddenly sounds as if it had received the same vitamin injections as Ben Johnson. The purr we remember from the drop-top E30 325i has given way to a growl that suggests this car never withdraws its claws. Redlined at 6500rpm, the 170bhp six will push the plastic bodied two-seater from 0-60 mph in 7.9 seconds and on to a top speed of 141 mph. The average fuel consumption is a frugal 30 6 mpg which indicates a driving range of 350 miles.
Up to around 70mph, the elements will destroy only your coiffure, but above that the degree of damage done depends very much on whether you have been wise enough to raise the doors. If you’re determined to leave them down.
I strongly recommend that you see the BMW boutique and buy the only two available Z1 extras, a leather cap and a pair of matching goggles. Thus equipped, you can still enjoy this roadster at twice the speed roadsters used to be built for. Without them, the Z1 is quickly reduced to a torture chamber that breeds burning eyes, sore ears and a running nose.
It takes a while to get used to driving without doors, but it takes even longer to get used to the true potential of the car’s incredible chassis, in the dry, on the open road, it is almost impossible to explore the limits of the Z1. The amount of roadholding, the sheer grip of its fat tyres and its neutral cornering attitude are simply out of this world. I drove the beast as hard as I could on the twistiest roads I could find, and the only obvious result was a pale-faced passenger who looked as if he’d just stepped out of the Oktoberfest’s Hell Ride. The car produced no break-away, almost no body roll, and certainly no oversteer. I had to find a dirt road before I could fire up the rear end, because on dry tarmac all the car would do was lean a little, squeal a little – and stay put. This suspension is so good that it does not need a good driver to tame it anymore.
However, while the suspension of Z1 is beyond reproach, the steering and the gearbox are not. The unassisted rack-and- pinion steering is not as quick and precise as it should be. It may be well-balanced and sufficiently light, but it does not quite match the dynamic qualities of chassis and engine. Similar criticism can be levelled at the five-speed gearbox which is well spaced and effortless, but also rather slow and stubborn. On the test car, changing down to second was always something of a gamble.
The ABS-equipped brakes, or, the other hand, leave nothing to be desired. Larger diameter and latter discs take care of fast and lade-free deceleration, and in the roadster you can at least smell when the hard-working brakes are beginning to sweat.
In Germany, the official Z1 price is around £26.500, but since production is sold out until the end of 1990, the going instant-delivery-rate on the black market is between £33.000 and £38.000. We are currently making six cars a day,’ says Faust. ‘Sometime next year, we hope to increase that to 10 cars, but with all the ifs and buts involved in launching a new product. I don’t see us doing more than 1500 Z1s per year. At this moment, we have not decided whether there will be a right-hand-drive version at all. Until the end of next year, BMW must concentrate on the domestic market. Exports to other EEC countries start in 1990, but if we serve the UK at all it may have to be with left- hand-drive models.’ So far, 3500 people have ordered a Z1, one of the most fascinating and controversial cars of the ’80s.
The cabin is as tight as two middle seats on Air Banana. Boot Is tiny. Door mirrors mounted on.
A-posts Wheels wear 225/45 P700s.
Instruments are smaller than normal, similar to a motorcycle’s.
Cabin Is tight lit, hard to got in and out.
Fittings and switches are mostly unique.
Klaus Faust (left), Z1’s project manager. Designer Harm Lagaay (right).
Push the button, and the door and window disappear.
Z1 is very small two-seater. Doors can retract into sills to increase breeziness.
Glassfibre panels clip onto monocoque, which uses steel skeleton, plastic floor.
Z1’s handling is superb: has more grip than any previous BMW.
Extra handling finesse, grip, due to chassis’ superb 49:51 weight distribution.
Engine BMW M20 M20B25 2.5-litre straight-six, as used in 325i E30. Positioned 10in further back.