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30 years of the BMW 7-Series

30 years ago, BMW’s "large class" spawned a successor that was to become a byword for luxury, elegance and innovation: the BMW 7 Series. Drawing on technology based on the large 6 Series Coupé launched in 1976 and styling that bore the signature of BMW’s chief designer Paul Bracq, BMW succeeded in creating a car that was larger than its predecessor yet managed to retain the hallmark dynamics associated with the brand.

The ingeniously tailored, understated bodywork borrowed its main styling cues from the BMW 6 Series Coupés. The gently sloping bonnet and boot, short overhangs and low beltline granted occupants excellent visibility, helped by a glass area that was 11 percent larger than its predecessor’s. The BMW engineers had also carried out modifications in the chassis technology and on the safety front. New features included front-wheel suspension with double-joint spring struts, a reduced steering offset and anti-dive, as well as a closed-shell rear axle subframe that offered far greater rigidity and improved corrosion protection. Like the other cars in the BMW portfolio, the 7 Series models also came with a centre rollover bar. In conjunction with all-round roof reinforcements and strong loadbearing pillars, this created a very large integrated safety structure to secure the survival space of occupants even in extreme impacts

With the newly launched BMW 7 Series joining the 3, 5 and 6 Series ranges, BMW now had a complete model family whose various members were instantly recognisable as being "related" thanks to their similar, yet distinctive, designs. "Visual and technical unity is now assured across all the model series," is how Hans-Erdmann Schönbeck, the sales director of the time, put it. "The BMW models are now indisputably a ’family’ once more with many shared features."

Initially customers could choose from three models: the 2.8-litre, 3.0-litre and 3.2-litre with 170, 184 and 197 hp respectively. Base prices were DM 29,300 for the BMW 728 and DM 33,600 for the 730, while an extra DM 5,000 would buy the top-of-the range 733i.

Even the BMW 728 boasted standard specifications that included speed-sensitive power steering, a diagonal-split dual-circuit brake system, inner-vented front brake discs together with a newly developed hydraulic brake servo, a laminated front windscreen, adjustable steering column and seat height, and an electrically adjustable exterior mirror. The BMW 730 ushered in the Check/Control system, an electronic monitoring unit that checked the level of the engine oil, brake fluid, coolant and windscreen washer fluid, as well as the functioning of the brake lights and rear lights, and the thickness of the brake linings. Beyond this, the top-ranging 733i featured not only a Bosch L-Jetronic injection system, but also boasted a contactless transistorised ignition, central locking, heat-insulating glass and a leather steering wheel.

In addition, customers could order from a long list of optional extras to equip their BMW 7 Series to personal taste. These included automatic transmission, a steel slide/tilt roof, headlamp washer and wiper, air conditioning, electric window lifts, self-levelling rear suspension, metallic paintwork, leather upholstery and separate electrically adjustable seats in the rear. The range of special equipment was augmented by "sporty extras" such as a limited slip differential, alloy wheels and a leather sports steering wheel.

The BMW 7 Series enjoyed an extremely successful market launch. At the Annual General Meeting of 7 July 1977, BMW’s Chairman of the Board Eberhard von Kuenheim announced: "The volume of orders is so unexpectedly high that the Dingolfing plant can barely keep up with production." Company turnover had risen by 32 percent the year before and BMW was turning out 24 percent more cars and 10 percent more motorcycles. The upward trend continued in the first half of 1977, which meant that the workforce again had to put in several extra shifts to keep up with the surging demand. To ensure that international customers could also buy the flagship car from the start, right-hand-drive versions were offered at an early stage. In July the first CKD kits were shipped out to the BMW plant in South Africa. December also saw the production start-up of a special version of the 733i targeted at the highly important North American market. In 1977 production figures for the BMW 7 Series ran to almost 20,000, a figure that would rise to 35,745 cars in the first full year of production and still exceed 35,000 units in the subsequent two years. The bottom line was that the BMW 7 Series was more successful than any previous BMW model series in its class.

The early years of the 7 Series already saw the regular addition of further optional extras. In 1978 BMW began offering its Anti-lock Braking System (ABS). To make driving BMW’s top-of-the-line model even safer and more comfortable, it also launched features such as an anti-theft warning system, driver’s vanity mirror and heated door locks, heated seats, onboard computer, cruise control, sunblinds for the rear windscreen and automatic air conditioning. For business people who spent a lot of time on the road, telephone preparation was also available.

From late August 1979 the large BMW six-cylinders were offered exclusively with fuel-efficient injection engines. The BMW 728i with an output of 184 hp replaced the 728, and the previous 733i was renamed the 732i. While displacement and output remained unchanged, enhancements included the newly developed digital engine electronics, incorporated for the first time in a BMW production model. This system used a microcomputer to calculate the precise ignition angle and quantity of fuel to be injected in any operating conditions. A newcomer to the range was the BMW 735i with the 3.5-litre 218 hp engine familiar from the 635CSi.

Ready for delivery in early summer of 1980, the new top-of-the-range model of the first-generation 7 Series - the BMW 745i featuring a 252 hp six-cylinder engine with exhaust turbocharger and 3-speed automatic transmission as standard - was handed over to the first customer. The model designation derived from the conventional formula applied to turbo models in motor sport at the time: engine size multiplied by a factor of 1.4 gave you the displacement class in which the turbo cars were deployed on the race track. For the BMW 7 Series with its 3210 cc displacement, the calculation produced the figure 4494. The 3.2-litre turbocharged six-cylinder delivered driving performance that was hard to match in the saloon sector.

Outside the official product range, and therefore unnoticed by the public, BMW produced a 725i model powered by the 150 hp engine taken from the BMW 525i and designed for use by public authorities, whose cars were frequently restricted to an engine size of 2.5 litres. To ensure that these potential customers still had the option of choosing a 7 Series model, BMW decided to install the tried and tested engine from the 5 Series. By the time production was phased out in April 1986, a total of 921 examples of this special model had been built. Similarly targeted primarily at public bodies, BMW introduced a reinforced version of the 7 Series as a security vehicle in 1981.

In September 1982 a number of technical and visual changes began to be phased in as part of a model revision. On the outside the hallmark BMW kidney grille was slightly flatter, the air intake in the radiator grille was smaller and the panel under the bumper had been modified. The top-of-the-range 745i now had a 3.4-litre engine under its bonnet, though output remained unchanged, as well as a 4-speed automatic transmission. The BMW 735i and 745i also came with the option of Executive leather upholstery at an extra cost of DM 3,390. Model year 1984 brought the option of a 4-speed automatic transmission with electric-hydraulic control and three shift modes. In the autumn, the BMW 7 Series range was augmented by two more luxury models: the BMW 735i Highline and the 745i Highline with high-luxury specifications.

By the time this series was discontinued in June 1986, production figures had hit 285,029. The most popular model was the 728i, which sold 70,360 times, followed by the 735i with sales of 60,818. A total of 16,848 BMW 7 Series alone went to South Africa as CKD kits. It was here, too, that the most powerful of the BMW 7 Series found a market. Early 1984, practically unobserved by the European public, saw the launch of a special version of the 745i powered by the four-valve-per-cylinder, naturally aspirated M88/3 engine from the BMW M1. Thanks to its L-Jetronic fuel injection system, output was boosted to 290 hp, while power was managed by either a 5-speed sports gearbox or a 4-speed automatic transmission with electronic-hydraulic control and three shift modes. BBS Mahle provided the alloy wheels and Pirelli supplied the proven P7 tyres in 205/55 or 225/50 spec. Its technology and interior equipment were adopted by the European BMW 7 Series Executive models. On the outside, this 745i was identifiable by hubcaps bearing the old BMW Motorsport logo, while inside the car only the speedometer featuring the letter M and the Motorsport stripes indicated that the engine nestling underneath the bonnet was anything out of the ordinary. Boasting a top speed of 241 km/h, the South African BMW 745i was only marginally slower than the almost 300 kg lighter BMW M5. By May 1986, only 192 models of this rare breed had left the factory.

The US market also offered a special variant of the BMW 7 Series, known as the L7. Even among BMW connoisseurs, this model designation is generally only familiar from the third-generation 7 Series, when the car was offered to the Arab and Asian markets with a longer wheelbase and an inserted centre section. However, in autumn of 1985 an L7 model appeared on the American market in which the L stood for "luxury". This model corresponded in almost every respect to the European BMW 735i Highline, although it offered a range of additional standard equipment such as a driver airbag, electric sliding roof, air conditioning and heated seats.

But the BMW 7 Series not only stood for dynamism and luxury; it was always a byword for innovation, too. The early 1980s, for example, saw the inception of a pioneering experiment: in collaboration with the German Test and Research Institute for Aviation and Space Flight (DFVLR), a BMW 735i and 745i were converted to so-called bivalent operation on either liquid hydrogen or petrol. By then BMW had already recognised the environmental credentials of hydrogen and the fact that, as a secondary energy source, it offered virtually unlimited long-term availability. The systematic pursuit of this path would lead, after almost 25 years of development work, to the launch of the first hydrogen-powered production model in late 2006: the BMW Hydrogen 7.

Source: http://www.topspeed.com/cars/car-news/30-years-of-the-bmw-7-series-ar40519.html