BMW X6 M50d - In-depth new car review by MotorBar's experts

“The BMW X6 M50d is a huge,
triple-turboed diesel version of
BMW’s X6 coupe-styled Sports
Activity Vehicle. Although it’s
only a four-seater it’s huge in size
and weighs in at 2,450kg — and
with 545lb ft, it most certainly
talks the torque...”

THERE IS DEFINITELY NOTHING SMALL about the X6's image, particularly the M50d — it's bold, brash and curvaceous on the outside and plush on the inside. It's also very fast, with uncompromising performance with road-going 4x4 traction all wrapped up in a coupe-styled four-door-plus-tailgate bodyshell.

Having a 4x4 drivetrain and a high-off-the-ground stance it can be used away from the tarmac but it isn't really useful for anything more than tracks or the shallowest of mud. The huge 20-inch alloy wheels are wrapped in enormously fat tyres that grip the road but sit on top of mud and, I suspect, they'll do the same with on-road snow.

Of course, it's highly unlikely the X6 will see much off-roading — more likely they'll be driven at great speeds on motorways to and from the country by city-slicker businessmen and professional footballers; all people to whom size and image matter.

“It’s not just the 381bhp
of power or the
huge 545lb ft of torque
that’s big — so too
is the price...”

It's not just the 381bhp of power or the huge torque that's big — so too is the price: Ł62,280. Other non 'M' X6 versions are available from as little as Ł46,740, which would buy you one of the most popular 30d version — and even that isn't exactly slow...

This in-line six-cylinder triple-turbocharged engine is the most powerful diesel unit produced by BMW. It has also been added to the X5, five-seater SUV range. Both versions have an eight-speed automatic transmission as standard. Top speed for both is restricted to 155mph and the zero to 62mph acceleration time is 5.3 seconds for the X6 and 5.4 for the X5.

Should you care, the X6's Combined Cycle fuel economy is 36.7mpg — just 1mpg less than the X5 version; CO2 emissions are 204g/km (X5: 199g/km). The X6 M50d incurs a significant first year road tax bill: Ł600 reducing to Ł270 for the second year onwards. The marginally CO2 cleaner X5 M50d gets away with Ł460 and then Ł250. Company car drivers — and that will be virtually all users — will pay 34% Benefit-in-Kind tax (X5 M50d: 32%).

Like its other X stablemates, the X6 coupe range has just undergone styling and specification changes for 2012/2013. In particular the X6 M50d changes include modifications for aerodynamic and technical reasons, as well as making it instantly identifiable from lesser X6 variants.

The three-section front apron channels more air into the engine bay through the outlets normally used to house the foglamps; air-channelling flaps beneath the apron also increase stability. New rear aprons feature openings for the trapezoidal tailpipe finishers. And there are grey front air intake bars and mirror housings, the latter underscored by the high-gloss trim matching that on the side window surrounds.

“The X6 M also receives
aluminium brake
callipers — in blue —
and becomes the first
BMW model to
include adaptive LED
headlights
as standard...”

Other styling touches include the telltale BMW 'M' identifiers on the door sills, boot lid, instrument cluster, engine cover and gearshift lever. The interior, unique to this version, features Alcantara and Nappa leather sport seats, Anthracite headlining and brushed aluminium interior trim.

There is, as you'd expect at this price, a vast array of high-level kit and a host of extra-cost options. Most useful was the standard-fit parking distance control plus the optional side view camera (Ł320) and the reversing assist camera (Ł530).

Combined, all three made parking and reversing much easier than it could be. Even being a six-footer, because of the vehicle's width and high waistline (not to mention the restricted rear and rear quarter visibility due to the coupe body design), reversing and parking without these aids would have been daunting.

The only visibility aid missing was a wash/wipe for the heavily sloping rear tailgate, which attracts huge amounts of road dirt scooped up by the tail-end vacuum created at speed. The 'falling' rear roofline also restricts headroom for the two rear seat passengers.

The X6 M also receives aluminium brake callipers — in blue — and becomes the first BMW model to include adaptive LED headlights as standard. In addition, to further boost its 'power' image, this particular model gains an impressive power-dome bonnet.

The X6 M50d rolls on 20-inch alloys which despite their huge size do not — fortunately — destroy the ride quality. It's as firm as it needs to be but not unduly so, and the big fat run-flat tyres mop up all but the worst pothole impacts. While these tyres will be of little use off-road or in snow, on blacktop they do provide endless grip.

Powering the X6 M50d is the most powerful BMW diesel engine ever: a six-cylinder, inline unit of 2,993cc, it's the first to feature three turbochargers.

“Powering the X6 M50d
is the most powerful
BMW diesel engine ever:
and it’s the first
to feature
three turbochargers...”

The integration of two small, variable-geometry high-pressure turbos and one larger lower-pressure turbo ensures instantaneous response throughout the rev range by ensuring the charge pressure is maintained at exactly the right level for the load on the engine at any moment.

One of the two small turbochargers is activated at engine speeds just above idle, allowing its low moment of inertia to instantly respond to any movement of the accelerator.

As the revs increase to 1,500rpm, the flow of exhaust gas reaches the large turbocharger ensuring that peak torque of 545lb ft is attained and maintained from 2,000rpm until 3,000rpm.

At 2,700rpm a vacuum-modulated exhaust flap opens, allowing exhaust gas to flow past the second small turbocharger and so creating additional charge pressure allowing maximum power of 381bhp to be available from 4,000-4,400rpm.

In conjunction with BMW's EfficientDynamics technology, including Brake Energy Regeneration, the updated high-pressure common-rail injection system of the new engine ensures good fuel efficiency potential and low emissions.

Fuel is injected into the engine at an increased pressure of 2,200 bar, with three pre-injections, one main injection and four post-injections taking place in one stroke of each piston. Officially, for the EU Combined Cycle, this engine should return 36.7mpg; in reality my test driving week, using all types of roads from motorways to country lanes, resulted in 28.7mpg — not bad at all given the performance, in particular the 'grunt' this engine provides right through the driving range.

“The X6 M50d drives
through all four wheels
via BMW’s intelligent
electronic xDrive system.
By integrating with the
Stability Control
Function, xDrive allows
a typically BMW
rear-drive bias — all
clever stuff!”

The eight-speed Sport automatic 'box has been configured to enable rapid gearchanges with an uninterrupted flow of power. There are two automated shift programmes — D and S — but the driver can also opt to change gear manually via the gearlever or the steering wheel-mounted shift paddles.

With a bespoke chassis configuration, the X6 M50d drives through all four wheels via BMW's intelligent electronic xDrive system. By integrating with the Stability Control Function, xDrive allows a typically BMW rear-drive bias.

But the system can intervene in milliseconds to enhance stability through the Dynamic Performance Control function by braking the appropriate rear wheel while simultaneously increasing engine power and redistributing torque to other wheels. All clever stuff; and all done seamlessly.

The bodyshell and powertrain mountings, springs and dampers, power steering settings and the standard and optional chassis control systems have all been specifically tuned for the X6 M50d. Self-levelling air suspension is fitted to the rear, operating with electronically-controlled dampers with BMW's Adaptive Drive active anti-roll function.

Downsides: the price — it's expensive to buy and run (although probably not for the kind of customers who will buy and run them). Other drawbacks are only four seats and, more seriously, no wash/wipe for the tailgate's rear screen given that rear and rear-quarter visibility is already restricted due to the coupe design.

On the plus side, the X6 M50d has power and huge torque, serves up fast, flexible and hugely responsive acceleration with fantastic on-road handling for a large 4x4. It's also a long-legged cruiser yet fast and agile in cut-and-thrust driving, and cossets with its luxurious and comfortable interior. Finally, not only is this boldly-styled vehicle a technological masterpiece but it drives like one as well. — David Miles

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