► ‘Brain and brawn in BMW’s best’ from CAR, March 1979
► CAR‘s first experience of the stunning BMW M1 supercar
► Conceived by BMW, designed by Giugiaro, developed by Lambo
► ‘A triumphant blend of Teutonic efficiency and Latin flair’
March 1979: So the dream has come true: the mid-engined supercar conceived by BMW, designed by Giugiaro and developed by Lamborghini is on the road
The speedo is reading 160mph as the car pelts down the straight. At the bottom of the mile-long concrete ribbon. Hans Stuck brakes hard, changes down into third, then goes back on the power as he enters the wide left hander. He opens the throttle hard and pushes the car past neutrality and into a controlled but spectacular drift. Its angle widens as the throttle is floored fully towards the exit of the bend; there, Stuck tickles the throttle and the wheel and sets the car straight again for the jump that follows. A couple of laps later your heart gets used to the rhythm of accelerating, braking and cornering: it is clear that this is a beautifully balanced and developed car. On the straight, you dare to take your eyes off the road to look around the cockpit. It gives you an impression of distinct sportiness and functionalism. But take a closer look: there is thoughtfulness and comfort for the driver too. The windows open and close at the push of a button, air conditioning keeps the tight cabin at the right temperature, and the backlight is of course heated.
The wide tunnel which separates driver and passenger in their bucket seats is the heart of the space frame, which is welded together from rectangular steel sections. This rigid backbone makes it possible for the door sills to be kept low: the car is only 44in high but even a driver as tall as 6ft 4in Stuck has no difficulty getting in or out. Headroom for tall drivers is limited though; a German brief has not conquered Italian design there. But in every other way, BMW’s new mid-engined M1 supercar emerges as a triumphant blend of Teutonic efficiency and Latin flair. It was, of course, conceived by BMW Motorsport boss Jochen Neerpasch as the device that would enable him to go to motor racing with a coupe well into the ‘80s, with the enormous benefits in prestige the 400 cars necessary for homologation would also bring to BMW. Faced with designing and developing such a car in a very short time, Neerpasch turned to the Italians. The design of the body was entrusted to Ital Design: the chassis, the development of the vehicle as a whole and its final assembly were given to Lamborghini, with BMW supplying their own in-line, six-cylinder power pack. Ital design gave the Germans the sort of shape they wanted: something that bore some resemblance to their own old mid-engined Turbo showcar; something that would look as if it belonged to Munich rather than Turin or Modena. Working closely with the Germans, Lamborghini set about designing the car’s chassis, building prototypes and getting developmental work underway. Ing Dallara, the wizard responsible for the Miura and much of Lamborghini’s outstanding suspension work, and now a consultant to Sant’ Agata, was an active participant in the M1’s chassis development, bring the project his views on working with the special properties of the Pirelli P7. Thus the M1’s suspension was developed in parallel with that of the P7-shod S-type Countach.
Six prototypes were despatched to Munich and Lamborghini had two more developed to the point where the car was gaining a reputation around Modena as being something very special: drivers who had it go whistling past their 3.0litre V8 Dinos and Urracos were among the first to learn that the presence between its loins of an inline six rather than a classic Modenese V-form engine was apparently no drawback at all. The Number Three Line within the Lamborghini factory was re-worked ready for the M1’s production to begin early last year. But then Lamborghini’s crisis was upon them: the £1.1m loaned by the Italian Government to enable them to buy in the components and actually build the M1 had somehow been salted away elsewhere and when the time came for BMW to go on the line there just weren’t the funds to make it possible.
That left poor BMW high and dry. They didn’t want to break with Lamborghini, but short of lending the Italians more money themselves (and the Munich board had long since proclaimed that no Deutschmarks were to be invested in Italy) there was nothing they could do, but urgently make alternative arrangements. They needed the project, and it had proceeded too far to be aborted. Through ex-Lamborghini people like finance man Capllini and engineer Raimondi, who set up a company called Ital Engineering immediately after bailing out of Lamborghini last summer, BMW were still able to get the vital components from the suppliers Lamborghini had found. Engineers called the Marchesi brothers agreed to weld up the tubular space frame chassis, and, with the fibreglass specialists TIR near Modena supplying the panels, Ital design were persuaded to mate the bodies and chassis at the premises they have near Bologna. What an Italian pit-pourri!
To overcome the problem of final assembly, BMW turned to the specialist Stuttgart coachbuilders Baur, who are best known for the sleek Bitter CD coupe they built around Opel Diplomat parts. So the bodies and chassis now come from Italy to Stuttgart to meet up with the engines and transaxles that BMW themselves supply direct to Baur. By the time sales of the car – at a cost of £26,500 – began in February (almost a year late, but remarkably impressive in the circumstances) Baur had finished 40 M1s, with a target of 400 due this year to meet BMW’s homologation commitments; another 400 will follow next year.
The road-going M1, BMW are anxious to point out, is a development of the car they conceived for racing – rather than the racer being a spin-off from the road car. The base they used in drawing up the chassis specifications was the 470bhp Group Four racer, with the road car giving off in one direction and the ultimate 850bhp turbocharged Group Five car in the other. The chassis is thus a lattice work of square section tubular steel, torsionally very strong and incorporating good roll-over protection. The body panels, entirely unstressed, are riveted or glued to the steel frame. The suspension is consistent with both Modenese and race-car practice: alloy hub carriers located by unequal length wishbones, with tight adjustable coil springs encircling adjustable Bilstein dampers, lots of anti-dive and anti-squat geometry (beyond that needed to extract the best from the P7s) and heft anti-roll bars. The Pirellis – 205/55VR16 and 225/50VR16 – run on rims 7in wide at the front and 8in wide at the rear, and the wheels have distinctive flat shapes to reduce aerodynamic drag.
The engine is based on the 3.5litre in-line six used in the 635CSi, but has been developed to a point where the two powerplants have few details in common. An oversquare 93.4mm by 88mm bore and stroke provide a total capacity of 3453cc. But while the block height is the same as in the 635CSi, the conrods are longer so that the pistons had to be redesigned. The cylinder head is new, a sandwich affair with its upper half carrying twin overhead camshafts and bucket tappets and the bottom half containing the 24 thin-stem valves, the combustion chambers and ports. A roller chain drives the cams, rather than a toothed belt. Kugelfischer-Bosch mechanical fuel injection sorts out the aspiration with the help of six gleaming throttle trumpets. There is an electronic ignition too, with a 7000rpm cut-out, and, down below, a dry sump eliminates the problems of oil surge. The compression ratio is 9.0 to one, and the power the engine packs is a very impressive 277bhp at 6500rpm with 239lb.ft at a high 5000rpm: seven hours’ bench-testing ensures that each engine reaches these ratings. The transmission is a five-speed ZF transaxle with curiously high internal ratios – fourth is substantially overdriven, and the 0.704 fifth is grossly so. A fairly brisk 4.22 final drive ratio (with a 40percent limited slip factor in the differential) does something to redress the balance. Overall, the M1 is 171.1in long; its wheelbase is 100.8in, its width 71.8in and it has a track of 61in at the front and 62in at the rear. All ready to go, it weighs 2867lb.
Martin Braungart, the M1 project engineer within BMW Motorsport, says: ‘When we split with Lamborghini, they’d already taken the car to a very impressive level of development. But their test driver Stanislao Sterzel had done more work on the Nardo circuit than on the road, and with the Italians unable to complete their programme we really had to start at the beginning again.
‘We devised a special 250mile test route that took in our own test track near Munich, a little-used stretch of autobahn in lower Bavaria and lots of secondary roads – we usually used them under cover of night. We also went to the Nurburgring and it was really there that the M1’s potential became full evident to us since we could relate our figures to those computed by Porsche and our other competitors. Even though the ‘Ring, with its frequent changes of direction and hills actually favours cars with conventional layouts, the mid-engined M1 was faster against the stopwatch than we had ever dared to hope.
‘But our work went hand-in-glove with what the Italians had done, and you cannot pinpoint a stage in the car’s development where their influence faded and our own ideas prevailed. We did not have to make any drastic changes: all the work with suspension settings, was, for instance, evolutionary rather than revolutionary. Of course, the Pirelli P7s are a great benefit to the car. They help to build up a cornering force around 1g, terrific stopping power and absolute high-speed safety. Yet there are a few drawbacks with the P7 and we haven’t been able to eliminate all of them. For instance, there is enough noise transference on certain surfaces to be irritating, and there is a trace of tramlining under braking. But we are prepared to accept such modest compromises to obtain the best possible handling and roadholding. The development of the Pirelli P6 might take us one step closer to perfection, and there are exciting new tyres to come from Dunlop and Goodyear as well.
‘What we did discover in our test programme were a few faults Lamborghini had overlooked. For example, the body showed signs of deterioration in some areas. We eliminated them before production began, but since the M1 is handbuilt and although we are very happy with the quality of the bodies the Italians are building, the car will never have the level of build quality it has taken Porsche 15 years to achieve with the 911.’
Of the long months of testing with the eight prototypes – many more than the Italian supercar makers would normally employ; quite apart from having the wealth to pay for such an ambitious programme, BMW were concerned lest the M1 be less durable than they would consider consistent with their reputation – contracted BMW race and development drive Hans Stuck says: ‘Our test circuit even included some rally stages, and we really thrashed the cars around it. An engineer called Dieter Gerzog used to come with us to keep an eye on all the test instruments, but his stomach could usually only cope with one lap, and then we would have to read them all ourselves, watching mainly for deterioration or breakages of vital components. As we progressed towards the ideal blend of roadholding, handling and comfort we were reaching increasingly higher average speeds; driving faster and faster. In the end I started believing the stopwatches were packing up. This kind of month-in, month-out testing really sorts a car out and I have no hesitation in saying that the M1 is now very, very well-developed. In fact, driving the first of the production models, it strikes me that I can’t think of any another supercar that has quite the same degree of refinement and durability.’
Out on the track, Stuck stops the talking and gets on with the driving once more. The engine is terrifically flexible – capable of trickling along at 1000rpm in fifth without fuss of fouled plugs – but it is far more impressive for its responsiveness. And it delivers real power as it rockets through the rev range; enough to have the M1 at 60mph in 5.6sec if you do it right – and that’s fairly and swuarely in the upper echelon of the supercar league. With the engine full out, it provides 50mph in first, 74 in second, 106 in third, 139 in that long fourth and 162 in top. The ratios make it easy for the driver, when he wishes to extract the utmost from the M1, to keep it in the fire-and-fury 4500 to 6500 rev band. There, it has a wealth of punch, and a really good throttle linkage gives the toes finite control: you can play this car so accurately on the throttle.
When the engine is at full cry, or when you’re cruising at something around 130mph, it becomes obvious that BMW have put a lot of effort into insulating the cabin. The engine is only 10in behind the occupants’ heads and yet the noise level is quite modest for a mid-engined car. Such is the degree of insulation in the firewall that, although the heat from the engine helps keep the upper glass panel fog-free it does not raise the cabin temperature: the air conditioning is there to look after that side of your comfort anyway.
Giugiaro’s aerodynamics work. The M1’s Cd is a modest 0.38 but the shape has a natural stability – Stuck runs the thing out flat and, with just over 160mph on the clock, you are aware of the degree of directional accuracy and purpose the car is displaying. Its sheer grip in bends is no less impressive, and it doesn’t seem to make that much difference whether the road is wet or dry. Push it in fast and this is a car that very quickly gives you the confidence to do that: it exposes itself to you, lets you read it easily – and there is very, very slight understeer. You detect it as a feeling of stability and know that you need to turn the wheel just a little more rather than finding the nose widening its line. You soon learn to keep the power on hard, and that the car will react to it by sitting down, the wheels four-square upon the road (part of the suspension geometry’s secret is minimal camber and caster change) to simply howl around the bend. Perhaps the most notable feature of the car is that, power full on, it remains in a period of absolute neutrality for an extraordinarily long time. When it does break away, it goes cleanly but very quickly, and you’ll need a clear mind and swift reactions to give it what it asks. That, in reality, is just a short, swift, dab of opposite lock. It comes back as cleanly as it breaks away, with very taut body motion and little tendency to over-correct. Put the think in Stuck’s hands, and he’ll push it through that period of neutrality to rip-roaring oversteer and use the precision of the throttle control and the edge of the engine’s power to hold the car in a long, long drift, sideways as hell, sweeping it round in a clear and steady arc to the apex and then bringing it straight again with effortless but precise wheel and throttle action. Experience such a demonstration and you know that this car handles as sharply and is as finely-balanced as any mid-engined car there is.
And if it doesn’t back the sheer excellence of its cornering with a pampering ride it has a comfort level that is still very good. The springs are in fact set quite soft, ready to let the wheels move easily over the bumps, but the Bilsteins dance to a firm tune, helping to provide the car with its poise and control. So you feel them doing their job at low speeds and on very awkward surfaces, but few would be the passengers who would complain of discomfort, and few the drivers who would not be thankful for the level of communication that they transmit. It’s the same with the steering: the rack is unassisted, the effort needed to swing the wheel modest, the results excellent and the information fed back ideal. Your foot tells you the same care has been taken with the braking: there is servo assistance but there is plenty of feel in the system, and the performance of the four big, inner ventilated discs is up to the sort of storming Stuck likes to dish out.
It’s a thing of efficiency, this BMW: the instruments are clear and laid out for easy reading. The wide, low binnacle jutting up from the main dash selection that houses them also carries normal BMW-style vertically-sliding levers for the air conditioning, heating and ventilation. Fully-adjustable grated air outlets are let into the lower edges of the economical fascia; and the stereo system lurks tidily in the upper part of the central console. The balance controls, the rockers for the rear demist, hazard flashers and fog lights are in the flat section beside the gearlever (which has first back and to the left, with the upper four gears in the main H). It’s a business-like, almost stark cabin. But no driver will find much to argue about once he’s underway. And, make no mistake, that’s what this BMW is all about – real performance, and the trimmings or lack of them that go with it.