BMW announced today an early Christmas present for BMW 3-series and Z4 fans - a biturbo version of BMW's inline six-cylinder engine.

Featuring the twin-turbo setup, "high-precision" direct injection, and an all-aluminum crankcase, the new engine pumps out 306 hp and an impressive 289 lb-ft of torque. (The normally aspirated straght-six puts out 265 hp.)

BMW estimates that the biturbo will hustle a 3-Series sedan from 0-100 km/h 0.5 seconds faster than the normally aspirated version.

More pics and the full press release after the jump.
[Source: BMW]
Biturbo and direct injection assemblies

Biturbo module

BMW Press Release:

The highlight in BMW’s Engine Park in Geneva is a new power unit making its world debut at the event: BMW is presenting the first straight-six power unit with biturbo technology, high-precision direct gasoline injection, and an all-aluminium crankcase. Using this combination of cutting-edge features, BMW’s engineers are able to combine outstanding performance, exemplary running smoothness and a high standard of economy with one another in a way never seen before. Developing maximum output of 225 kW/306 hp and peak torque of 400 Newton-metres or 295 lb-ft, this 3.0-litre power unit is the new top-end engine within BMW’s wide range of six-cylinders.

Superior Efficiency for Supreme Performance:
BMW Presents the Future of the Turbocharged Power Unit.

A new top-of-the-range power unit featuring biturbo technology and direct gasoline injection will mark the highlight of BMW’s six-cylinder engine family in future. Developing maximum output of 225 kW/306 hp and peak torque of 400 Newton-metres or 295 lb-ft, this highly innovative new engine fulfils the greatest demands also in terms of spontaneous and superior power. As the first straight-six with biturbo technology, high-precision fuel injection and an all-aluminium crankcase, this new highlight in engine technology offers a standard of responsiveness never seen before with a turbocharged engine as well as superior torque and pulling force all the way to the engine’s highest speeds. And at the same time this new turbocharged power unit comes with the supreme smoothness and refinement so characteristic of BMW’s straight-six engines.

The particular efficiency and all-round economy combined with this supreme output and performance is attributable to BMW’s high-precision fuel injection, the latest generation of direct gasoline injection by BMW making a significant contribution to the all-round economy of this trendsetting engine.

So now, introducing this combination, BMW’s engineers are writing a new and particularly attractive chapter in the history of turbocharged power units 100 years after the invention of the turbocharged engine.

Proven foundation: the straight-six power unit.

Introducing this new turbocharger technology, BMW is meeting the demand for extra power in both a thrilling and highly efficient manner. Particularly with the concept chosen by BMW, turbocharger technology is simply ideal to maintain the proven drive qualities of the engine and open up new highlights. The foundation for all this is laid by BMW’s current generation of straight-six power units displacing 3.0 litres and developing maximum output of 195 kW/265 hp and thus offering a potential quite outstanding for a normal aspiration engine. Now, to generate even more power and, in particular, torque, BMW is adding biturbo technology to this excellent starting point. Compared with the proven 3.0-litre normal aspiration engine, biturbo technology increases overall output by approximately 15 and peak torque by an even more impressive 30 per cent.

The result is clear: maximum output of 225 kW/306 hp and peak torque of 400 Newton-metres or 295 lb-ft. which, on the road, means outstanding thrust and driving power all the way up from low engine speeds. And what this
means in practice BMW’s engine development specialists have already calculated, taking the BMW 3 Series Sedan as an example: The biturbo version would accelerate from 0–100 km/h more than half a second faster, with acceleration from 80–120 km/h (50–75 mph) in the second-highest gear improving from 8.2 seconds in the most powerful normal-aspiration version, the BMW 330i, to just 6.3 seconds in such a new model.

The only way to achieve such an increase in power and performance with a normal-aspiration engine would be to significantly increase engine size, which would also mean a corresponding increase in weight and corresponding effects on the car’s overall balance. By contrast, the combination of turbocharger technology with high-precision gasoline injection is a particularly efficient way to meet even greater demands in terms of output and torque. And for comparison, the new straight-six biturbo weighs about 70 kilos or 158 lb less than an approximately equally powerful eight-cylinder normal-aspiration engine displacing 4.0 litres. A further essential point is that the power unit equipped with high-precision fuel injection offers about 10 per cent lower fuel consumption than an equally powerful turbocharged engine with manifold injection.

Apart from its low weight and fuel economy quite superior in its class, the new biturbo is able to offer yet another particular quality feature so typical of a BMW straight-six: This is supreme smoothness and refinement, precisely the virtue which has made BMW’s straight-six power units the benchmark for refined drive technology acknowledged the world over. Indeed, right from the start the specific arrangement of the cylinders gives the engine perfect balance in terms of free mass forces, avoiding vibrations even at high engine speeds. A further important point is that this turbocharged version of BMW’s six-cylinder comes with the same extra-light camshafts as on the normal aspiration engine, variable, double-VANOS camshaft adjustment, as well as an electrically driven coolant pump operating only as required (that is as a function of current cooling requirements).

The turbo “gap” – a thing of the past .

Developing this highly innovative power unit, BMW’s engineers have also succeeded in eliminating the former disadvantages of turbocharged engines attributable to their concept and design principle. Hence, BMW’s new turbocharged six-cylinder is absolutely free of some not so desirable characteristics so typical of turbocharged engines to this very day: There is not the slightest delay in the development of power and thrust, and at the same time the engine does not have the same high fuel consumption as a conventional turbocharged power unit.

Particularly the biturbo concept ensures a significant improvement of spontaneous power, two smaller turbochargers each supplying three cylinders with compressed air, instead of just one big turbocharger for all cylinders together. An essential advantage of these turbochargers is their lower inertia, even the slightest pressure exerted by the driver on the gas pedal leading to an immediate surge of power and performance. In other words, the turbo “gap” so typical of turbocharged engines so far – the time-lag until the turbocharger starts to build up power – is no longer perceptible. On the road, therefore, this new turbocharged engine has virtually the same power and performance characteristics as a much larger normal-aspiration power unit: The 3.0-litre develops its impressive torque of 400 Newton-metres or 295 lb-ft without any noticeable delay consistently all the way from 1,500–5,800 rpm. And from there the engine continues to rev up smoothly all the way to 7,000 rpm, offering the driver a particularly superior standard of dynamic performance for accelerating all-out in superior, relaxed style.

Double progress: high power, high efficiency.

To combine a fascinating driving experience with up-to-date fuel economy, BMW has developed the world’s first straight-six gasoline engine with biturbo technology, direct gasoline injection, and an all-aluminium crankcase.
From the start, the turbochargers make an important contribution to the reduction of fuel consumption, with the turbines made of high heat-resistant special steel withstanding temperatures of up to 1,050 °C or 1,920 °F and therefore not requiring the cooling effect of extra air flow. Particularly under full load, this means a significant decrease in fuel consumption.

The key function serving to maximise fuel economy is however BMW’s high-precision fuel injection. Indeed, this new generation of direct fuel injection technology fulfils all expectations made in practice in terms of superior economy, without making any concessions in terms of dynamic performance and driving qualities. High-precision fuel injection allows even more exact dosage of fuel as well as a higher compression ratio – ideal conditions for increasing engine efficiency and significantly reducing fuel consumption.

All this is made possible by the central position of the piezo-injector between the valves. Fitted in this position, the innovative injector opening to the outside is able to distribute fuel in a conical burst ensuring particularly smooth distribution of fuel within the combustion chamber.

Developing this new straight-six with biturbo technology, BMW is opening up a new chapter with an engine principle basically quite old: Only recently, the turbocharged engine celebrated its 100th anniversary, with turbocharger technology registered for a patent by Swiss engineer Alfred Büchi in November 1905 having played a significant role for decades particularly in boosting the output of marine and aircraft engines. In series production, on the other hand, all turbocharger concepts used so far have always had the unpleasant side-effect of increased fuel consumption – and indeed, this conflict of interests appeared insurmountable for a long time. Only the latest developments in engine technology have opened up the door to the new approach BMW is now following consistently, combining turbocharger technology with high-precision fuel injection as the ideal concept for efficient dynamics in particularly fascinating style.
Now the new high-performance power unit marking the pinnacle of BMW’s straight-six engines impressively proves the fascinating potential of this concept and its most important components. With its superior responsiveness and equally outstanding pulling force, the new engine soon reaching the standard for series production opens up brand-new dimensions in driving dynamics.

Indeed, BMW’s engine development specialists even have further options and concepts in view for this engine and its technology: Over and above the drivetrain conceived and built for supreme dynamics, this technology provides the starting point for a lean-burn direct injection concept and thus serves to successfully optimise fuel consumption also in other performance classes. In this way BMW is once again proving its competence in engine construction, developing modern, up-to-date drive concepts and at the same time enhancing that sheer driving pleasure of BMW to an even higher standard.

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