Motoring is more than just a fast and comfortable means of transport. Beautiful, alluring alpine passes encourage competition, and conquering these wide open roads becomes a sporting activity.

At the Berlin motor show in 1934, BMW unveiled it’s first self-engineered roadster alongside the 315 saloon. The attractive lines and 6-cyclinder power unit of this elegant two-seater, unbeknownst at the time, went on to be the core of today’s Z4 roadster.    

Compared with the 315 saloon, the roadster had excellent streamlining due to the tapered rear end, and thanks to the radiator grille being inclined much further towards the rear end. To reduce air drag, the rear wheels were fully covered, while the body of the car itself rested on an electrically welded steel-pipe double frame with three crosswise box elements. Front suspension was made up of the upper track spring, wishbones further down and hydraulic lever-type dampers. The rear wheels, in turn, were mounted on a live axle incorporating semi-elliptic springs and hydraulic lever-type dampers.

Small but hot: six-cylinder power unit displacing 1.2 litres.
Both the saloon and the sports car were powered by the same outstanding engine: a 1.5-litre straight-six, developed out of the 1.2-litre originally featured in the former BMW 303. The crankcase and cylinder block of the engine were made of a single piece, with one camshaft beneath the block, and tappets operating the vertical hanging valves. Finally, to paint the picture, the intake and exhaust pipes were on the same side.

The power unit delivered maximum output of 34 hp in the saloon with its two carburettors, but the maximum output of the six-cylinder in the BMW 315/1 sports model was 40 hp. Therefore the standard of efficiency offered was quite exceptional, BMW’s engineers proudly stated, “this beautiful and fast sports car is no more expensive than a small car far lower down in the market”.

The climax of the pre-war era for BMW was the 328 Roadster.
In the mid-30s, production roadsters and competition cars were still very similar in technical terms – and motorsport was still the ideal place to prove the performance and reliability of a production car. But to keep up with the competition, BMW soon had to build cars with more power and muscle. So BMW’s engineers looked for ways and means to significantly increase engine output without increasing engine size. And they found the solution – the M328, the engine powering the legendary BMW 328 sports car in 1936.

BMW’s roadster pulverised it’s most powerful and supercharged competitors. This outstanding success was attributable to the well-balanced combination of superior engine power and cutting-edge suspension technology, characteristic of BMW roadsters to this day: 80 hp in the regular version and a low weight of just 830 kg gave this elegant roadster superior performance. But again, the BMW 328 Roadster remained a very rare model, with only 464 units of this classic roadster being built up to 1940.

While the 328 paved the way for BMW’s sporting activities, the Company’s next two-seater sports car set new standards in design and elegance as of the mid-50s: the BMW 507. When making its debut in New York in 1955 the 507 left both journalists and the public absolutely spellbound. The long and sleek engine compartment; the cockpit perfectly tailored to the driver and passenger; the short and muscular rear end; stretched side lines and gently sweeping curves gave the car absolutely beautiful, timeless design. At the same time the 507 came with a brand-new, but nevertheless clear and impressive BMW face: the double kidney grille was now vertical instead of horizontal. The 507 also had a lot to offer within the engine compartment, boasting an aluminium V8 acknowledged to this day as the first light-alloy V8 in the world built in series production.

This truly exclusive car went to exactly 251 proud owners between 1956 and 1959. And not all of them wanted to enjoy this beauty merely as a café cruiser. Racing driver and the “King of Hill-Climbing” Hans Stuck, used a modified 507 in mountain races in Europe, winning a number of events in his eight-cylinder roadster.

The BMW Z1 was launched – ahead of its time in technical terms, in 1988. The body of the Z1 was a steel monocoque made of pressed and welded metal panels. The entire outer skin was made up of plastic elements and panels bolted on to the car, with the doors retracting on request into the high side-sills even while driving. The 170-horsepower, 2.5-litre straight-six power unit (and most of the car’s axle components) came from the 3 Series. With the engine behind the front axle, the BMW Z1 was a front mid-engined car and acceleration from a standstill to 100 km/h came in less than eight seconds. With a top speed of 225 km/h or 140 mph.

Through its extremely harmonious combination of materials and technologies the BMW Z1, weighing just 1,250 kg was a truly dynamic roadster still thrilling today in terms of stiffness, its low centre of gravity, and stability in bends. The first units of the car built largely by hand were delivered to customers from January 1989, with a base price of DM 80,000. Production of the BMW Z1 finally ended in June 1991, after a run of 8,000 units.

Sheer driving pleasure in large numbers: the BMW Z3. The BMW Z1 was the breakthrough, as such, more and more enthusiasts now showed growing interest in an open BMW two-seater. In response BMW launched a roadster in 1995, built in large numbers for customers worldwide. This compact performer became the epitome of BMW’s classic virtues, offering well-balanced technology within a truly attractive body.

The BMW Z3 entered the market with a choice of two engines. Featuring a 1.8-litre four-cylinder two-valve power unit developing maximum output of 115 hp, the “regular” model accelerated to 100 km/h in 10.5 seconds and reached a top speed of 194 km/h or 120 mph. The other option was a four-valve 1.9-litre four-cylinder delivering maximum output of 140 hp for acceleration to 100 km/h in 9.5 seconds and a top speed of 205 km/h or 127 mph. With the Z3 proving to be a huge success, a range of different engines meeting all kinds of different demands were produced. Ultimately, the portfolio extended from the original 1.8-litre four-cylinder all the way to the 3.2-litre six-cylinder high-performance power unit carried over from the BMW M3, delivering up to 325 hp in the M Roadster and giving BMW’s compact sports car truly outstanding performance on the road.

On entering the new millennium, BMW proudly presented a very special new model: the BMW Z8. With its sleek proportions, classic lines and soft folding roof, the Z8 was one of the most outstanding cars of its time through looks alone. Measuring 4.4 metres or 173.2" in length, 1.83 metres or 72.0" in width, and 1.31 metres or 51.6" in height, this was indeed a modern interpretation of the former BMW 507.

Within its engine compartment the BMW Z8 featured a high-performance five-litre V8 sports engine delivering 400 hp. Combined with a manual six-speed gearbox, this supreme engine enabled the driver to enjoy the utmost in performance at all times and under all conditions. Indeed, this superiority translated into equally clear facts and figures. Ambitious Z8 drivers were able to lap the 20-km Nord-schleife of Nürburgring in staggering 8:15 minutes.

The new BMW Z4 followed the Z8. It was presented for the first time at the Paris Motor Show in September 2002. From the start, this open two-seater not only marked a new pitch in BMW design language, but also set new standards in its class. Available from the start with a choice of two high-torque straight-six power units, the Z4 – either in the guise of the 231-hp Z4 3.0i or as the 192-hp Z4 2.5i – guaranteed roadster motoring at its best.

The outstanding agility of the BMW Z4 is ensured by the car’s wide track, an extremely low centre of gravity, optimum 50:50 axle load distribution, and the very precise electric power steering. Fading-free high-performance brakes, run-flat tyres featured as standard, and Dynamic Stability Control (DSC III) with an add-on traction mode all guaranteed supreme driving safety under all conditions.

The modern interpretation of the classic roadster launched in spring 2009, combines more power and style than ever before. Indeed, this is the only car in its segment to combine classic roadster proportions with the seating position moved far back close to the rear axle, rear-wheel drive and a fully automatic retractable hardtop. The new BMW Z4 offers all the driving pleasure of a BMW roadster in a particularly refined style. Here, it is certainly appropriate to quote the “BMW Blätter”, the original BMW Leaflets in their description of the BMW 315/1 back in 1934: “In a nutshell you can describe BMW’s new sports car as the fast, beautiful and reliable car bound to give the ambitious sports driver one exhilarating experience after the other, at the same time combining all the advantages of an economical touring car.”

A strong yearning for one of the afore mentioned alpine passes takes over…

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