The BMW M550d xDrive is one hell of a beast. It may not be seen as such by some people, who consider diesel engines to be unworthy of being used on passenger cars but having driven one, I can wholeheartedly tell you that this would be the perfect car to change their minds. The quad-turbo 3-liter straight six engine under the hood is a monster and can deliver 400 HP in standard guise, making it the most powerful diesel engine of this size in the world according to BMW.
Unfortunately, the M550d xDrive might also be going out of production, as BMW hinted a couple of times that making it is quite expensive and that not a lot of people buy it to compensate for the R&D costs. Nevertheless, we must enjoy it while it lasts and some tuners even put out tuning kits for it, to infuse even more power in it. The guys from AutoTopNL had a tuned M550d xDrive for testing purposes and they filmed a couple of videos of it.
Their car was tuned at McChip-DKR, a Belgian company known in the EU for its rather outrageous power output claims and measly prices. According to the company the M550d xDrive can develop 515 HP and 865 Nm (638 lb-ft) of torque, a rather noticeable improvement. It’s quite interesting to see this thing in action too, as BMW claimed – when unveiling the new B57S engine – that they could’ve squeezed more than 760 Nm (560 lb-ft) of torque out of it but were limited by the gearbox.
I also posted a video of a stock BMW M550d xDrive going from 0 to 100 km/h (62 mph) to compare the two and get a better grip of how much faster the upgraded model is. The tuner claims the car will do the sprint in 3.8 seconds, 0.6 seconds faster than stock. The top speed is also claimed to have been increased to 295 km/h (184 mph).