BMW may have created the world’s fastest diesel 4x4, but the thirsty brute isn’t quite Frederic Manby’s cup of tea
APART from the question “Why?”, the BMW X6 M50d is a remarkable vehicle. It is the only car I have driven with three turbochargers and by far the most powerful diesel. The rakish SUV not only outperforms any diesel Range Rovers but also the five-litre supercharged petrol V8 model and beats them on economy and emissions. No Mercedes-Benz diesel has anything like its horsepower and only Audi gets close with its 4.2 litre V8 diesel in the seven seater Q7.
BMW’s hottest 3-litre diesel combines a 0-62mph time of 5.3 seconds with an official 36.7mpg and 204g/km CO2. The eco figures improve slightly for the BMW X5 M50d fitted with the same chassis and power system. They are the first diesel BMWs to receive the full M performance rating for the British market, which brings the triple turbo straight six engine, beefier suspension and brakes and M signature details. The gearbox is 8-speed automatic driving 4x4 traction with variable torque sharing between the 20-inch alloys.
Maximum power is 375.7bhp and the torque is 545 lb ft. The price of £62,280 is nearly £16,000 more than the regular twin turbo diesel but it includes the marque’s adaptive drive system. You also get leather seats, parking sensors, self-levelling rear suspension, climate control, remote operation of the tailgate, metallic paint and a smattering of M decals. Without these there is not much to give the game away. The “powerdome” bulge on the bonnet is the most visible ID at the front – used also on the petrol X6 M model. Open it up and there’s no visual need for the dome, just more space over the engine.
The triple turbo thing is one of the major talking points for The Camshaft Arms. They come on stream sequentially as the revs rise, so that beyond 2,600rpm all three are pumping fuel with gay abandon into the cylinders. It’s a jolly thrilling thing, accompanied by a harmonious roar from the engine. However, the gearing is such that at these revs in the higher gears you will be soaring past speed limits. (At 70 in eighth it is running at well under 2,000rpm.) Too much fun with the loud pedal will also diminish levels in the fuel tank, which holds a useful 18.7 gallons (85 litres). A typical read-out on the dashboard showed around 32 miles a gallon, up to 34mpg and down to 29mpg. These figures are not far off BMW’s official ratings and not bad for a vehicle weighing 2.2 tons and capable of such high performance. They are, though, too thirsty for my high mileage life.
The ostentatious X6 per se is also not my sort of vehicle. Even an X5 (or Mercedes ML) I find rather attention-grabbing and shy-making. If I needed 4x4 traction then I would have an excuse but most of these high-end 4x4s do little more than pose – and gobble up fuel stocks.
Style has not only overtaken function with the X6 but is having a bit of a laugh. The high rear deck and sharply sloping roof (mimicked by the Range Rover Evoque – which looks tiny against an X6) eat up the potential load space. The seats will fold flat but the load aperture is limited by the roof height and the tailgate lip.
The body design restricts rearward vision and I had to struggle to reverse safely. I also almost “missed” some overtaking vehicles. A “blind-spot” indicator would have helped.
Other compromises crop up. Rear headroom is not terrific and you’ll have to pay extra if you want a middle rear seat: without it you cannot legally carry three rear occupants.
The M50d carries massive tyres on those massive wheels and has a corresponding level of road noise. The other disappointment was the ride comfort. While it can corner with more poise than you’d hope for, there is too much suspension clatter on ordinary roads and in a bend a sudden bump can jiggle the front wheels.
If you are getting the impression that an X6 is not “my cup of tea” you are right. Also, the M50d version is far more than you should pay for one unless you can afford the fastest diesel SUV in town. On top of the £62,280 you’ll need £290 for the useful aluminium side steps, £215 for roof rails, £250 for a third rear seat, plus various amounts for sundry technological gizmos.
It is: BMW X6 M50D. World’s fastest diesel 4x4. 0-62mph in 5.3 seconds.
For: Did I say it was rapid?
Against: Jitters on a variety of everyday surfaces. Tyre noise. Poor rear visibility – plus no rear wiper to clear rain. Rare BMW without stop-start ignition. Navigation queue-dodging advice failed to avoid a jammed M25. The speed limit display was not always correct.
Length: 192 inches.
Pace: 0-62mph in 5.3 seconds.
Green stuff: Officially, 204g/km CO2 and 36.7mpg are creditable for its 2225kg bulk and blistering performance. On test it showed 25mpg to 34mpg.
Good for: Turning heads.
Bad for: Carrying beds.
Verdict: If no one could see me and someone else paid for the diesel I may get to like one of these.