Smart technology powertrain systems are all set to give BMW’s next new cars better performance from less fuel.

Fresh engines and an advanced eight-speed transmission unit will boost petrol economy by 8% in the new 3.0-litre petrol 5 Series GT and make the revamped 740d model 4% more efficient.

Due on sale in October, the 5 Series GT - which made its UK fleet debut at the Greener Company Car in Action last month- will also boast an additional 6% economy bonus by featuring an automatic gearbox with a higher top ratio for more relaxed cruising.

BMW claims combined fuel eceonomy of 31.7mpg and CO2 emissions of 209g/km.

In September, the low-friction transmission will also be teamed with the German firm’s next-generation 3.0-litre diesel TwinPower turbo engine in the top version of the 7 Series.

Producing 306bhp and with 442lb-ft torque available from only 1,500rpm, this engine is claimed to set a fresh benchmark in diesel driving.

The 740d will return a claimed average of 40.9mpg and emit 181g/km of CO2.

BMW Group drivetrain development chief Wolfgang Nehse said: “So far, we have produced 1.35 million EfficientDynamics vehicles that embrace aerodynamic changes, lightweight technology and alternative drive concepts, but it is significant that we are now using big, high performance cars as the forerunners of new developments for greater efficiency.

“Our new six-cylinder petrol engine for the GT is the world’s first to combine turbocharging and direct fuel injection with Valvetronic, our fully-variable valve management system.

"It is unique – and the output of our new turbodiesel allows it to take over from its predecessor as the most sporting and dynamic six-cylinder diesel in the world.”

To be offered as an option to the current six-cylinder diesel, the new engine has a revised twin-turbo system and piezo injectors operating at up to 2,000 bar for higher efficiency.

bAnd despite having extra ratios, the new transmission weighs no more than the previous six-speed unit.