While word has been going round that the upcoming G11 BMW 750d will see Munich’s tri-turbo diesel mill swapped out with a quad-turbo unit, BMW Blog has stuck its head out to say that the new quadruple turbodiesel will have 395 hp, five horsepower less than the 400 hp previously indicated by some.

Details on whether the fourth turbine would be a traditional unit or electronically-spooled are still unknown, but the quad-turbo engine is likely to be paired to an eight-speed automatic transmission and BMW’s xDrive all-wheel drive system.

At the moment, the German marque’s most powerful diesel powered engine is the N75S 3.0 litre tri-turbo engine with 381 hp and 740 Nm. It consists of two smaller turbines and a large one which gives the engine a consistent charge of power as it rises up the rev band.

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Currently, the new G11 BMW 7 Series in 730d form is powered by a 3.0 litre turbodiesel with 265 PS and 620 Nm of torque. That, and the tri-turbo’s 381 hp/740 Nm is the bar that the new quad-turbo motor must comfortably clear.

The 3.0 litre tri-turbo engine can be found in the F10 BMW M550xd, the BMW X5 M50d and the X6 M50d. After its debut in the 2016 BMW 750d, the quad-turbo should end up in all those AWD models as well.

G11 BMW 730d