BMW Z3 and Z4

The Complete Story

James Taylor

• Editore: Crowood
• Anno: 2017
• ISBN:
  9781785002779
• Argomento: Technologie et ingénierie
• Categoria: Transport et ingénierie de l'automobile

BMW, that most performance-oriented of car companies, had no affordable sports roadster in its line-up before 1995. Stung into action by Mazda's revival of the classic two-seater roadster, the Germany company quickly staked its claim with the Z3, a classic long-nose, short-tail design that used existing BMW mechanical hardware to good effect. This new book tells the story of BMW's Z3 and Z4 two-seater roadsters and coupes, which since 1995 have been at the forefront of the affordable sports car market. The history of the Z3 and both generations of Z4 are covered as well as full specifications of all models; the formidable M Power derivatives and a guide to buying and owning. The book is profusely illustrated with over 200 colour photographs and diagrams. Contents include: Historical background to BMW's arrival in the two-seater sports car market; Complete history of the Z3 and both generations of Z4; Full specifications of all models; The formidable M Power derivatives; Guide to buying and owning.

CHAPTER ONE

A SPORTING HERITAGE

As a much-admired builder of sporting machinery, BMW was in an extraordinary position for most of the 1980s. For the German car maker had no traditional sports car in its model range. Nobody doubted the performance and handling qualities of its top models, and nobody doubted the excellence of its engines, but there was no open two-seater available with the blue-and-white roundel badge.

The reasons for this were many and varied. Perhaps most important of all was that by the 1980s BMW had only just pulled off an astonishing recovery from near-extinction at the start of the 1960s, and that building such frivolities as a sports car had been put on the back-burner until the company was back on a sound commercial footing. And yet without a sporting undertone to the products of its revival, BMW would have found those years of recovery much more difficult. Competing in a German domestic market dominated by the solid and superbly engineered cars of Mercedes-Benz, and where the lower-priced sector was well catered for by the likes of Opel, Ford and Volkswagen, BMW had to be different. That sporting undertone was what made it different.

Although there was probably an element of calculation about distinguishing itself from rival manufacturers in this way, it was certainly not an idea that had been picked out of the blue. In earlier years, BMW had enjoyed a reputation as a builder of sporting machinery that had included traditional open two-seater models. In fact, it was cars like this that had made its reputation in the first place.

In the Beginning

BMW’s early years had been spent as a maker of aero engines, and the company’s name actually reflected its beginning in that industry. The letters BMW came from Bayerische Motoren Werke (‘Bavarian Engine Works’), and from 1916 the company had focused on building some of the best aero engines around. However, the opportunities to sell those engines became rather more limited during the 1920s when Germany was caught in the grip of rampant inflation and reconstruction of its military powers was severely restricted by the humiliating Treaty of Versailles that the country had been forced to sign in 1919. So BMW began to look around for additional ways of deploying its talents and its factory space.

One industry that was booming in the 1920s was that of the motor car. Everywhere that cars were being made, synergies were being discovered between the design and manufacture of cars and aeroplanes, and it made sense for BMW to look at the possibility of moving into the car industry. The opportunity arose in October 1928 when the small German car maker Dixi, based at Eisenach, ran into financial difficulties. BMW did not hesitate and bought it out and, for the first few months, continued to run the company under its original name as a subsidiary.

The 1931 3/15 DA2 model, derived from Britain’s Austin Seven and with saloon bodywork by Ambi-Budd in Berlin, seems a far cry from the sleek BMWs that came to characterize the marque. Yet the sporting ambition was already present: the chassis was available with a two-seat roadster body as well.

At this stage, Dixi was best known for building a version of the British Austin Seven under licence. The Austin Seven had been carefully designed to offer the minimum of everything that was needed in a car, in order to keep its price low and attractive, but it had also been designed to offer more than the ultra-cheap cyclecars of the time. The formula was an attractive one, and was eminently suitable for a Germany where economic circumstances were difficult. So Dixi took on manufacture of the Austin design in 1927, adding a few features of its own to give the car extra appeal to German buyers.

Once BMW had taken over, the Dixi name was dropped, and the upgraded 1929 models became known as BMW 3/15 models – the 3 was the 3PS taxable horsepower rating and the 15 was the actual power output of 15PS (14.8bhp). During 1930 the original three-model range (saloon, convertible and delivery van) was expanded to include a sports roadster – BMW’s first – with a drop-centre front axle to lower the car’s centre of gravity and an 18PS (17.75bhp) version of the engine. Known as the Wartburg model (after a castle overlooking the town of Eisenach), it was withdrawn after just a year as the sports car market collapsed in the Great Depression. In 1932, the licence manufacturing agreement with Austin expired, and BMW chose not to renew it. By this time, they were ready with their own car designs.

As the BMW 3/20 appeared in 1933, the German economy was just beginning to look up under the leadership of the National Socialist Party. While ruthlessly suppressing political opposition and asserting German nationalism, the Nazi party did succeed in improving job prospects and reining in inflation. The building of new Autobahns provided an opportunity to create new touring cars and saloons, and BMW did exactly that alongside other new sports models such as the 315/1 of 1934.

The Roadsters of the 1930s

The 1934 315 (not to be confused with the earlier 3/15 model) was designed by BMW engineers and was made available with this attractive roadster bodywork.

The 315/1 – presented at the Berlin Motor Show in May 1934 – was the first roadster engineered by BMW’s own designers. Based on the chassis of the company’s existing 315 saloon, it had a more steeply raked radiator, just two seats behind a low windscreen, a folding roof (really for weather emergencies only) and a tapered tail. To reduce wind resistance in the fashion of the times, its rear wheels were hidden under spats. Like the saloon newly introduced at the same show, it had a 1.5-litre 6-cylinder engine developed from the 1.2-litre type used in the earlier BMW 303, but in the sports car it had 40bhp as against the 34bhp in the saloon, and in production form that sports car was capable of 75mph (120km/h).

BMW campaigned the cars itself, well aware of the value of sporting success in impressing a car’s qualities on the buying public. These are 315/1 roadsters at the 1934 ‘2,000km across Germany’ race, in which BMW won a gold medal.

The 315/1 quickly established its sporting credentials with success in the 1934 International Alpine Rally, run between Nice and Munich over a distance of 2,867km (1,781 miles). One of the five works-entered cars finished first in its category, and all five completed the rally without incurring any penalty points at all. Over the next couple of years, the little BMW became a serious contender in motor sport events, driven by both works and private drivers, and a ‘special’ built by Ralph Roese was still winning races in 1939, when Roese carried off the German Road Racing Championship. Meanwhile, BMW had capitalized on the car’s success by making a more powerful version available – this time with a 1.9-litre engine tuned to 55bhp. Called the 319/1 and available between 1934 and 1936, the car was another success in competition, although its high retail price kept sales relatively low.

Much in the same mould as the 315/1 but far more powerful and modern in concept was the BMW 328 roadster of 1936. The wheel spats helped link the design back to the earlier 315 but were usually removed for sporting events to speed wheel changing.

Other manufacturers made strenuous efforts to outdo the BMW roadsters in the mid-1930s, and the company could not afford to rest on its laurels. Further engine development found higher outputs within the capacity constraints of the 2-litre class, and from summer 1936 BMW had another new contender. This was the BMW 328, whose new 2-litre engine would be used not only for the sports car but also to power BMW’s larger road cars, both saloons and grand touring cabriolets. In overall charge of the 328’s development was Fritz Fiedler, and there were significant contributions from Alex von Falkenhausen and Ernst Loof, who would later play important parts in the history of BMW after the Second World War.

The 328 roadster became a competition favourite. Here, a clutch of examples contest an event held in the City Park at Hamburg during 1939.

The 328 was introduced as a specialist sports-racing machine at the Eifelrennen race in June 1936, where it won the 2-litre class. The model became available as a road machine as well and during 1937 achieved more than 100 class wins in competition. In 1938 it won its class at Le Mans and won the RAC Tourist Trophy, the Alpine Rally and the Mille Miglia, following that in 1939 by another RAC Rally win and a class first (plus fifth overall) at Le Mans. A special works coupé won the 1940 Mille Miglia at an average speed of 103.6mph (166.7km/h), but by that time war had broken out and many potential competitors stayed away from the Italian event.

The 2-litre BMW engine was used in the elegant 327/28 coupé – a 327 model of the late 1930s fitted with the higher-powered engine of the 328 roadster.

In the Doldrums

During the 1940s and 1950s, BMW was in very bad shape. At the end of the Second World War in 1945, the company had lost one of its major factories (at Eisenach) to the Russian-controlled eastern sector of the country, and for the next few years struggled to survive in the harsh postwar economic climate from its main factory in Munich. It restarted motorcycle production somewhat hes...