New BMW X6 M50d review, test drive

The new X6 M50d just has to be one of the most charismatic performance SUVs around. Shapur Kotwal tells you why.

Published on Jul 22, 2015 06:00:00 AM

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The new cabin also gets a much more useable rear seat, with better support and space. You can now seat three abreast in comfort. The new X6 also gets a pair of neatly trimmed kneepads for the driver. They flank the centre console to provide supportive leg-bracing when the cornering forces get large, preventing that typical pain in the knee you experience on hard driving.

Under the skin, the X6 M50d is also pretty special. Despite being one step down from a full M car, it gets plenty of bespoke hardware that makes it feel extra special from behind the wheel. The chassis of the standard car is a bit stiffer than the outgoing one. In addition, this full-time four-wheel-drive X6 also gets the so-called adaptive M Sport suspension, which firms up considerably in the Sport mode. Add in a dynamic pack and you also get active roll control and a rear axle that distributes the engine’s power to the rear wheel with the most grip.

Under the hood sits BMW’s most recent gem — a smooth, free-revving diesel six with not one, not two, but three turbos! The M50d’s 3.0-litre, triple-turbo straight-six produces 381bhp and commercial vehicle-like torque of 75.45kgm. All this is achieved because BMW has reduced the compression ratio of this diesel to just 16:1, really low considering few petrols nowadays come with a 12:1 ratio. The lower compression allows for greater ‘fill’ from the three turbos at maximum boost, and BMW has made sure injection pressure is good enough to supply plenty of diesel. The M50d’s injection pressure is upped to a really high 2,200bar when the engine is running at max speed.

How do the three turbos work together? To begin with, a small variable-geometry turbo comes in at low revs. This allows for fast responses and a reduction in lag as the light turbo is easy to spool up even with a small tap on the throttle. There is a hint of lag as you take off, but the quick eight-speed gearbox ratios help you overcome this in a jiffy. The larger main turbo joins the fray at just 1,500rpm, and takes responsibility for most of the meaty midrange. So, after 2,000rpm, responses are massive and explosive bursts of acceleration are just a flex of your right foot away. The third turbo is small again and chimes in at approximately 2,600rpm, helping give the mid range a boost. The best bit is that the turbos overlap so smoothly, you really need to pay attention to notice where each comes in, especially if you accelerate flat out in one long seamless pull all the way to 5,600rpm.

As a result, the X6 M50d is really quick. This 2.2-tonne SUV does 0-100 in an insane 5.3 seconds, and that’s just the start of it. And the manic pull in the higher gears simply has to be experienced. The motor delivers huge thrust from 2,000rpm to 5,000rpm, and the manner in which it progresses up the powerband is so undiesel-like, you almost forget it is one. Yes, it growls like a diesel in the midrange under load and there’s a hint of clatter too, but there’s also a nice snarl in the top end that sounds just great. At speed, the X6’s most remarkable feature is its near-petrol-like hush.