BMW unveils biturbo 3.0-litre six with the same power and more torque than the 4.0-litre eight cylinder engine

And for comparison, the new straight-six biturbo weighs about 70 kg less than an approximately equally powerful eight-cylinder normally-aspirated engine displacing 4.0 litres. That is about the same weight as a moderately sized passenger.

Direct petrol injection also offers a significant fuel consumption saving of about 10 per cent compared with a similarly powerful turbocharged engine that uses regular fuel injection.

Turbines made of high heat-resistant special steel can withstand tem¬peratures of up to 1,050 °C and therefore do not need the cooling effect of extra air flow. Particularly under full load, this means a significant decrease in fuel consumption. High-precision fuel injection allows an even more exact dosage of fuel as well as a high¬er compression ratio – ideal conditions for increasing engine effici¬ency 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 en¬suring particularly smooth distribution of fuel within the combustion chamber.

Apart from its low weight and class-leading fuel economy, the new biturbo engine is able to offer yet another unique BMW feature. This is supreme smoothness and refinement, precisely the virtue which has made BMW straight-six power units the benchmark for refined drive technology, acknowledged the world over.

Indeed, the natural perfection of the straight-six layout 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 hollow, extra-light camshafts as on the normally-aspirated engine, as well as an electrically driven coolant pump operating only as required.

The history of the turbo

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