As of November, the ubiquitous BMW 520d is set to get a new mild-hybrid system. The setup comprises a 48V starter-generator and a second battery, and BMW says the additional power harvested 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 0-100kph in 7.3sec and has a top speed of 235kph, thanks to a 2.0-liter turbodiesel engine making 187hp and 400Nm.
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 liters 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 sedan and wagon, 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.
NOTE: This article first appeared on TopGear.com. Minor edits have been made.