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

Backing up its global success with the innovative 507 bhp V10 powerplant for the M5 and M6 super cars (2005 Engine of the Year), and the VALVETRONIC magnesium-aluminium straight-six engines introduced in 2005, BMW is set to tear the wraps off a production-ready biturbo version of its acclaimed petrol-powered six-cylinder. Retaining the familiar 3.0-litre capacity, the new all-aluminium engine boasts a pair of turbochargers, each feeding a trio of cylinders. When combined with the efficiency and flexibility of acclaimed BMW VALVETRONIC and double-VANOS technology, the new engine is able to produce an immense 225 kW of power and 400 Nm of torque. BMW claims that with the technologies it has employed in the new motor, the traditional bugbear of turbo lag has been vaporised and fuel consumption has been slashed.

The new engine is armed with a Table Mountain-like torque profile that defies the term curve. Peak torque of 400 Nm is delivered between 1,500 rpm and 5,800 rpm and the engine boasts a 7,000 rpm red line. The biturbo six-cylinder has the same power and more torque than the muscular 4.0-litre V8 engine fitted to the 740i. However, in keeping with BMW philosophy, the substantially enhanced performance does not come at a substantial cost to the environment.

Fuel consumption, previously a bug-bear of high-performance turbo-charged engines, has been radically reduced thanks to high-precision direct petrol injection, used for the first time on a BMW six-cylinder motor. The V12 powered BMW 760i/Li features direct petrol injection for its 6.0-litre engine.

A further traditional turbo-engine wrinkle has been ironed out by BMW engineers: turbo lag. In the new engine, this has been completely removed, thanks to low inertia turbochargers. The driver need only brush the accelerator pedal to receive an immediate surge of power and performance, as the engine delivers an electrifying response according to BMW's press information.

While turbocharger technology is almost as old as the internal combustion engine itself, in combination with cutting-edge high-precision direct petrol injection technology BMW engineers were able to write a new and exciting chapter in the history of forced-induction.

The foundation for all this power and torque is drawn from the exemplary characteristics of the magnesium-aluminium 3.0-litre engine which is rated at 195 kW (as fitted to the BMW 130i in Australia and soon to be available in the Z4 Roadster). This in itself is quite outstanding for a normally aspirated engine.

Compared with the proven 3.0-litre normally aspirated magnesium-aluminium engine, the all-aluminium engine featuring new biturbo technol¬ogy increases overall output by approximately 15 percent. Peak torque shoots up by an even more impressive 30 percent. The resulting 225 kW and 400 Nm of torque deliver outstanding thrust and driving power all the way across the rev range.

The only way to achieve such an increase in power and performance with a normally-aspirated engine would be to significantly increase engine size, which would also mean a corresponding increase in weight and the negative effects on the car’s overall balance.

The BMW combination of turbocharger technology with high-precision petrol injection is a particularly efficient way to meet even greater demands in terms of output and torque.

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