History of the BMW 3 Series

1975: the first generation - premiere as a two-door sedan with high-output four-cylinder engines.
The presentation of the first BMW 3 Series in July 1975 saw BMW write a new chapter into the automotive history books. The two-door sedan wasted no time in leaving its own distinctive stamp on the mid-size segment, with its compact dimensions and sporting character. The front end was dominated by the kidney grille and, at 4,355 millimetres long, 1,610 millimetres wide and 1,380 millimetres tall, the new arrival looked at once compact and grown up. Track widths of 1,364 millimetres at the front and 1,377 millimetres at the rear lent the car a powerful stance. All of which was very much in keeping with the state-of-the-art, sporty suspension - a MacPherson construction at the front and independent suspension with semi-trailing arms and spring struts at the rear.
Power was provided by four-cylinder engines with 1,573, 1,766 and 1,990 cc displacement, and the model variants would be christened 316, 318, 320 and 320i. With the exception of the fuel-injected engine, all the units were designed to run on standard petrol. In a dramatic break from convention, the design of the new model’s interior was centred around a concept that was to become a hallmark of BMW cars for many years - a driver-focused cockpit. A year later, readers of German motoring magazine "auto, motor und sport" voted the BMW 320 the world’s best sedan with up to two-litre displacement. In 1977 the BMW 3 Series welcomed the arrival of the first six-cylinder engine in the segment, the 320 and 323i models gaining disc brakes all round in preparation. The BMW 323i, in particular, quickly earned itself a reputation as a consummate athlete, using its 105 kW/143 hp to power effortlessly to a top speed of 190 km/h (118 mph). Performance, agility and sporty looks as the key reasons for buying a BMW 3 Series, and four out of five customers would purchase one again. The one-millionth BMW 3 Series rolled off the assembly line in 1981, after just six years in production.

1982: the second generation - four-door, Convertible, Touring and BMW M3, plus the first diesel engine for the sports sedan.
The new BMW 3 Series oozed progress and variety out of every pore, as its fresh new design, optimised aerodynamics, improved space and comfort, higher output and additional body and engine variants confirmed. BMW had consistently expanded the reach of its most successful model range and shown an unerring sense for what its customers wanted. This generation saw the arrival of a four-door family version (1983), the BMW 3 Series Convertible and the sporting BMW M3 (both 1985). Today the first BMW 3 Series Convertible is a prized "recent classic" among many fans of the brand. With the attractively styled Touring (launched in 1987), BMW showed that driving pleasure and practicality, and space and functionality need not be mutually exclusive in the sporty mid-size segment either. Moreover, the first diesel and first all-wheel-drive models were introduced into the BMW 3 Series range. It was a successful strategy: the second-generation car sold over 2.3 million units - one million more than its predecessor.
The introduction of the eta six-cylinder engine in 1984 heralded the development of a new economy-led concept. The 325e was powerful but also frugal and clean; this was the first BMW 3 Series model to be offered only with a catalytic converter. The powers-that-be in Munich also demonstrated considerable courage with the 324d, the first sporty diesel sedan in the 3 Series line-up. It was accompanied by the hugely powerful 325i, which came with permanent all-wheel drive in 325iX guise. The transfer case with viscous clutch allowed the use of ABS, which was duly fitted as standard on both models. 1989 saw the arrival of the 318is and with it the first volume-produced BMW four-cylinder engine with four-valve cylinder head.

1990: the third generation - premiere of the BMW 3 Series Coupé and BMW 3 Series Compact, new six-cylinder petrol and turbodiesel engines.
1990 saw the introduction of the third-generation 3 Series, the four-door Sedan taking to the stage on a wave of elegance and new technology. On top of this, the dimensions of the body and the space inside the car had both grown considerably. A two-door variant followed in 1992, and this time it was every inch the graceful coupé. Just a few months later BMW unveiled two more sparkling additions to the line-up: the new Convertible and new BMW M3. The developers came up with another fresh concept innovation in 1994 with the introduction of the BMW 3 Series Compact. It was welcomed by drivers looking primarily for greater economy, but without the need to compromise on dynamic performance and comfort.
The new six-cylinder engines had two camshafts and four valves per cylinder. In the Coupé the powerplants featured VANOS variable camshaft control. This new technology improved torque development and reduced fuel consumption and emissions, and allowed the engineers to increase the engine’s compression ratio. Two other newcomers to the range were the 325tds, powered by a six-cylinder diesel engine with turbocharger and intercooler, and the first four-cylinder turbodiesel under the bonnet of the 318tds. The turn of the year 1994/95 also brought a lighter aluminium crankcase for the six-cylinder units.

1998: the fourth generation - common rail direct injection, VALVETRONIC and BMW xDrive.
The fourth-generation BMW 3 Series generation was launched in May 1998 and brought with it another hike in output, comfort and safety. The new model was four centimetres (approx. 1.5 in.) longer and wider than its predecessor, and its interior had also grown accordingly. By the end of 1999 the BMW 3 Series had risen to third place in Germany’s registration lists, an unprecedented achievement for a car in this class.
The 320d gave a debut to the brand’s first direct-injection diesel engine, while the 318i was now fitted with two balancer shafts. The most technically noteworthy development among the six-cylinder petrol engines was the introduction of Double-Vanos. The continuously variable and fully automatic adjustment of both the intake and exhaust camshaft gave the engines more abundant torque and further reduced emissions. The high-output 330d diesel saw common rail injection take over fuel supply to the cylinders for the first time. In 2001 BMW presented the throttle butterfly-free load control system VALVETRONIC. This technology allows variable lift of the intake valves and boosts output while lowering fuel consumption and emissions. It wasn’t long before VALVETRONIC was introduced into series production.
BMW also presented a new all-wheel-drive system for the Sedan and Touring variants. BMW xDrive uses automatic brake inputs on a particular wheel or wheels to mimic the effect of conventional locks. Another new development came with the ability to distribute power fully variably between the driven front and rear wheels. The pioneering fourth-generation line-up also included the BMW 3 Series Coupé and Convertible, which were now available with diesel engines and cleverly combined the qualities of driving pleasure, styling and good sense.

2005: the fifth generation - BMW EfficientDynamics, High Precision Injection, TwinPower Turbo technology and a new CO2-beater.
The fifth, outgoing generation of the BMW 3 Series range celebrated its world premiere at the Geneva Motor Show. The new combination of powerful engines, dynamic and refined driving characteristics, striking design and innovative equipment was met with resounding approval around the world. Since 2007, the BMW EfficientDynamics development strategy has shown how the driving pleasure of the BMW 3 Series can be blended harmoniously with exceptionally low fuel consumption and emissions.
All petrol engines now came with the direct injection system High Precision Injection, which brought a fuel-saving lean-burn approach to both the 330i and 325i six-cylinder models and the four-cylinder 320i and 318i. In the BMW 335i, meanwhile, the injection system teamed up with TwinPower Turbo technology, two turbochargers and Double-Vanos. To keep weight as low as possible, BMW introduced a crankcase made from aluminium or an even lighter magnesium/aluminium composite.
By model year 2010 all the engines met the EU5 exhaust standard. For its part, the BMW 320d EfficientDynamics Edition was the most efficient car in the mid-size segment - with something to spare. The third-generation common rail direct injection unit developed 120 kW/163 hp, and fuel consumption in the EU driving cycle was just 4.1 litres of diesel per 100 kilometres (68.9 mpg imp). Over the past 36 years BMW has consistently expanded its leading position in the sporty mid-size segment. The BMW 3 Series range showcases its sporting roots - across a variety of model variants and output classes with greater conviction than any other car in its class. This has led to BMW repeatedly taking on the mantle of innovative trendsetter and leader, both in the development of engine and drive system technology and beyond.

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Article courtesy  of: http://www.bimmerfest.com/news/632519/video-history-of-the-bmw-3-series-from-e21-to-f30/