2018 BMW M550d xDrive Has Four Turbos And 400 Hp.

BMW is doubling its 5-Series M Performance models with the new diesel-powered M550d xDrive

Available in both sedan and the more practical Touring (station wagon) body styles, the M550d comes with standard rear-biased all-wheel drive, but it’s what lies under the hood that makes this 5er special. 

Improving upon the previous M550d that had a tri-turbocharged 3.0-liter straight-six, BMW’s engineers added a fourth turbo to create the world’s most powerful six-cylinder diesel unit. 

The two low pressure turbochargers that are new and replace the previous large-sized third turbocharger, are permanently powered during travel. The second high-pressure turbocharger kicks in at engine speeds of over 2,500 rpm. BMW says that at high load requirement from idling, the two low-pressure turbochargers are briefly circumvented by means of a flap control system to build up boost pressure even faster.

Retaining the same displacement as before, the quad-turbo’d lump has an output of 400PS (294 kW/ 395hp) at 4,400 rpm, and 760Nm (560 lb-ft) of torque delivered from just 2,000 rpm, which is more than the outgoing M5 (680Nm / 501 lb-ft). Fun fact – more than 450Nm (332 lb-ft) are available from as low as 1,000rpm. 

Power is transferred through a standard, M Performance-tuned 8-speed automatic transmission, with the M550d xDrive sedan accelerating from 0 to 100km/h (62mph) in 4.4 seconds and the Touring in 4.6 seconds. Both have an electronically limited top speed of 250km/h (155mph). 

Naturally, it wins hands down when it comes to fuel consumption with BMW quoting an average of 5.9 l/100 km (39.9mpg US / 47.9mpg UK) with CO2 emissions of 154g/km for the sedan and 6.2l/100km (37.9mpg US / 45.6mpg UK) with 163g/km for the Touring on the European driving cycle. 

As with the M550i, the diesel gains an M Sport suspension that lowers the body by 10mm, with an adaptive M Suspension Professional featuring Dynamic Damper Control offered as an option. The M550d also gets what BMW calls an Integral Active Steering with a variable rack-and-pinion ratio.

Elsewhere, the M550d features an M styling treatment with specific bumpers, the rear with a diffuser, side sills, blue brake calipers and a boot spoiler for the saloon. Cerium grey has been used on trim elements including the kidney grilles, door mirrors as well as on the standard 19-inch wheels shod in 245/40 R19 tires front and 275/35 R19 rear. If you want to go bigger,  20-inch wheels are offered as an option. 

Inside, beyond the illuminated sill trims with an ‘M550d’ inscription, the front passengers get contoured sport seats, while the cabin has been dressed in swaths of leather, Alcantara and aluminum trims. The M-specific steering wheel with shift paddles, pedals, and instrument display round out the upgrades over the regular 5.