At the 2017 Frankfurt Motor Show, it wasn’t just BMW that had a couple of noteworthy debuts on display, as its long-term partner Alpina as well. The tuner/manufacturer from Buchloe brought out the fastest diesel in the world, according to them, the Alpina D5 S AWD model. And while we did expect it to be based on the quad-turbo M550d xDrive, it’s not entirely the case.

The car Alpina brought is also using an engine based on the B57 mill BMW developed. However, while the quad-turbo B57S uses four turbos, the Alpina counterpart makes due with three. This configuration led a lot of people to think that this is actually an engine based on the older N57 3-liter tri-turbo, but the people from Buchloe told us that’s not the case. The D5 S AWD is, however, split into two main categories.

Apparently, due to the position of the steering wheel, right-hand drive models will only come with 326 HP while the left-hand drive versions will be able to benefit from the full potential of the tri-turbo 3-liter straight six mill under the hood and the 388 HP that come with it. On top of that, customers also get to bask in 800 Nm (590 lb-ft) of torque, more than what the M550d is offering, that model being limited to 760 Nm (560 lb-ft).

Couple that with all-wheel drive and the Alpina D5 S reaches 100 km/h (62 mph) from standstill in 4.4 seconds, 0.2 seconds slower on the Touring models. However, that’s not what makes them the fastest production diesels in the world but their top speed. The Alpina D5 S AWD can reach a top speed of 286 km/h (177.6 mph). One has to wonder though, if the 400 HP BMW M550d xDrive wasn’t electronically limited to 250 km/h (155 mph), would it be able to topple the offering from Alpina? I guess we’ll never know. In the meantime, let’s take a look at the first promo video published online featuring the new diesel monster.