What is it?
An executive saloon with a supermini’s CO2 emissions is something unusual, and the 520d Efficient Dynamics’ tax-saving ways will shortly make it the best-selling 5-series.
Like the smaller 320d ED, its frugality does not force a performance compromise. So it’ll do 144mph and, more usefully, hit 62mph in 8.2sec. You can only have the 520d ED as a manual saloon and without the M Sport upgrades favoured by many, but these sacrifices are small for the gains made.
What's it like?
BMW has won the gains with taller gearing, an active radiator cooling flap, stop-start, an intelligent alternator and more streamlined wheels. More subtly, the engine has a special centrifugal pendulum vibration absorber, which allows it to pull improbably low revs in high gears without provoking a grumbling vibro-massage through seat, pedals and gearlever.
It works, too, in tandem with a new Eco-Pro drive mode that encourages fuel-saving gearchanges into sixth from as little as 1500rpm. This mode is accessed via what BMW grandly describes as a Driving Experience Control switch, whose simultaneous adjustments of throttle response, ESP settings, steering resistance and automatic transmission shiftings produce Comfort, Sport, Sport+ and the aforementioned fuel-saving mode, which alters the functionality of the air conditioning and assorted electrical items to lower their energy demands.
Also provided are in-dash economy and gearshift indicators and a bar graph that shows fuel consumption history and also provides driving tips. These are a bit basic – 'moderate your acceleration' appears when you’re doing the opposite – but they can provoke some fuel-saving guilt.
Or you can ignore all this and enjoy the 520d as a subtly accomplished sports saloon of considerable refinement, the more so if you order the optional variable dampers, which yield the more connected sensations you’d expect from a car of lightly sporting intentions.
Should I buy one?
If you can bear the benefit-in-kind implications, there will be other options boxes you’ll want to tick too, but even without them this 520d makes a mighty impressive combination of performance, economy, civility and space.