We drove BMW’s top of the range (for now) 850i last month, now we’ve tested the entry-level (for now) 840d. As you might expect, its turbocharged 3.0-litre straight six has significantly less power than the turbocharged V8, but it is only down by a meagre ten percent in terms of torque, dishing up a healthy 680Nm. This means that in everyday driving it feels just as muscular and easily adopts the effortless loping stride you’d expect from this sort of large GT. Moreover, as with so many BMW diesels over the years, the engine feels much smoother and keener to rev than others in the genre.
The eight-speed gearbox works in tandem with the navigation to select appropriate gears (something first seen on a Rolls-Royce), but such is the torque on offer that you’d often be hard-pushed to know if it had made a Horlicks of it. You can of course use the paddles attached to the back of the steering wheel if you want more control, but for the best fuel economy figures you’ll want to let it shift itself and select Eco Pro mode, which allows the car to coast, when appropriate, and results in a claimed 46.3mpg on the combined cycle (compared to the V8 petrol’s 28.8mpg).
What is perhaps more surprising is that the 840d feels every bit as capable in the corners as the petrol car. The all-wheel drive system is pleasingly rear-biased, only delivering power to the front axle when absolutely necessary.
Meanwhile, the rear-wheel steer system means that the 8 Series displays remarkable agility for one so large. The steering is relatively light, but it remains extremely precise, meaning that the 8 Series can be threaded down a narrow road with absolute confidence.
Our test car was fitted with the optional £2500 M Sport Technic pack, which we would heartily recommend as it adds an M sport differential, high performance tyres and an uprated braking system. It also adds some aerodynamic styling tweaks to the handsomely sleek bodywork, making it all but indistinguishable from the over £20,000 more expensive petrol car – only a peek up the rather ghastly fake exhausts reveals two pipes instead of four.
Talking of exhausts, it is worth mentioning the sound. An unobtrusive hum is about all you get with the car in its Comfort and Eco Pro modes, but switch to Sport or Sport Plus and you’re treated to a pleasingly gruff growl. It is a sound largely piped through the Harmon Kardon speakers in the car, but while this might feel like cheating in something that should be more naturally sonorous it feels acceptably clever in a diesel.
A Bang and Olufsen stereo upgrade is available for those that can tell you not only which sea is in a shell but whether the tide is in or out, however, we found the standard system to be more than adequate.
The fit and finish of the rest of the interior also feels excellent and although the clean cut design of an Audi A7 centre console is more visually appealing, BMW’s decision to keep the iDrive’s wheel and button controls (in addition to the big touch screen) feels like the right one in terms of ease of use. More questionable is the optional Crafted Clarity handmade glass package, which turns the gear selector into something that looks like a stopper from a cheap whisky decanter.
As well as going quickly in a forward direction, the 8 Series is also very adept at going slowly backwards. Should you find yourself in a tight spot in a car park you might be grateful for something called Auto Reverse Assist. Simply press the appropriate button on the main parking sensor screen, engage reverse, control your speed with the pedals and the car will self-steer back along the path you took for the preceding 50m. Clever stuff.