As the Euro 6d emission standard comes into effect next year, BMW is introducing 48-volt mild hybrid technology to its straight-six diesel engines. The G30 5 Series and G32 6 Series are receiving this update in their mid-cycle facelift for the 2021 model year.
BMW has also announced that the G01 X3, G02 X4, G05 X5, G06 X6, G07 X7, and G11 7 Series will also receive this update for its I6 diesel engines from July 2020 for the 2021 model year.
It is uncertain, as of now, whether the more recent G20 3 Series and G15 8 Series will also receive this update for the 2021 model year.
The single-turbo B57D30O2 found in *30d and *30d xDrive models receives increases of power output by 15 kW / 21 hp to 210 kW / 286 hp and of torque output by 30 Nm to 650 Nm. Maximum torque is now available from 1500 to 2500 rpm, thanks to further refined BMW TwinPower Turbo technology, which now enjoys variable intake geometry in two-stage turbocharging. The common rail injection system has also been upgraded to deliver fuel at a maximum pressure of 2700 bar.
The twin-turbo B57D30T2 found in *40d and *40d xDrive models receives increases of power output by 15 kW / 20 hp to 250 kW / 340 hp and of torque output by 20 Nm to 700 Nm. Maximum torque is now available from 1750 to 2250 rpm. The turbocharging system now features variable intake geometry in both the high- and low-pressure stages.
As an example, the 7 Series sedans powered by these engines now gain 0.2 seconds on sprints from 0 to 100 km/h. The 730d variants save 0.6 litre of fuel per 100 km, while the 740d variants save 0.4 litre for the same distance.
48-Volt Mild Hybrid
A 48-volt starter generator is integrated to the straight-six diesel engines. They facilitate energy recuperation during braking, with a battery for storing the electric energy thus generated. The starter generator can support the combustion engine with an electric boost during acceleration.