BMW's new tri-turbo engine proves bigger isn't always better, eking V8-beating performance from a six-cylinder turbo diesel engine to mark a midlife update for the brand's controversial X6 SUV.
The X6 M50d features the first of a new M Performance family of engines to come to Australia, a triple-turbocharged 3.0-litre diesel unit that makes 280kW of power and 740Nm of torque.
The mountain of torque, which is about double that of a regular petrol-powered V6, the latter available from just 2000rpm.
It adds up to a 0-100kmh time of 5.3 seconds, shading the 4.4-litre V8-driven X6 xDrive50i by 0.1 seconds on the way to an limited top speed of 250kmh.
Another impressive figure is official fuel use of 7.7 litres per 100km, which is less than many compact SUVs can manage.
In what amounts to careful positioning by the marketing department, the X6 M50d still falls well short of the performance benchmark set by the X6 M that was released in 2009, which musters 408kW and 680Nm to reach 100kmh in just 4.7 seconds.
The V8 petrol-powered X6 M, however, uses almost double the fuel of the X6 M50d at 13.9L/100km.
The German prestige brand sold just 343 X6s last year compared to 2770 of its comparably-sized X5 that the sportier-looking SUV is based on.
But the X6 retains a halo role at the head of the company's SUV range, not least because of the eye- catching styling that polarises opinions.
The addition of the tri-turbo engine, in combination with an M Performance handling and cosmetic package, is the headline act in an otherwise mild makeover of the X6, which gets a mild front-end styling makeover designed to put more emphasis on the company's trademark dual kidney-shaped grille.
BMW describes the engine's power delivery as "a thrust which sets in early on and is maintained right through to the high engine speed range".
Two small, high-pressure turbochargers are supplemented by a larger low-pressure unit.
One of the small units activates just above idle, while the larger one kicks in at 1500rpm to ensure all 740Nm of torque is available from 2000 to 3000rpm.
If the driver keeps accelerating, an exhaust flap opens at 2700rpm to activate the third turbocharger, which helps deliver maximum power of 280kW between 4000 and 4400rpm before the engine reaches its redline cutout at 5400rpm.
The X6 M50d also wins some significant handling tweaks with self-levelling air suspension, stronger body mounting to reduce roll and adaptive drive, which includes electronically controlled dampers and an active anti-roll control function that reduces lean in corners.
The X6 M50d retails for $157,000 and heads an X6 range that kicks off from $121,000 for the X6 xDrive35i.
The tri-turbo engine will also be available on the X5 SUV, which also launched last week.
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