The BMW 5 Series is going mild-hybrid

As of November, the ubiquitous BMW 520d is set to get a new mild-hybrid system. Comprised of a 48V starter-generator and second battery, BMW says additional power harvested by the system will be used to power ancillaries and for an “electric overboost” function.

The company hasn’t said how boosty said function will be, which leads us to believe you’ll barely notice the difference. The existing 520d does 0-62mph in 7.3 seconds and has a top speed of 146mph, thanks to a 2.0-litre turbodiesel engine making 187bhp and 295lb ft.

We do, however, know how much more economical the mild-hybrid system will make it. BMW claims the 520d’s fuel consumption will be improved by as much as… 0.3 litres per 100km driven. Again, not a difference you’re likely to notice. Unless you drive vast distances and keep a detailed log of your fuel consumption figures. For fun.

The mild-hybrid system will be fitted to the 520d saloon and estate, as well as the xDrive all-wheel drive versions of both. And only the 520d – for now, anyway, no other 5 Series gets this tech.

Click here to read the full BMW 5 Series review.