How many turbochargers can you fit into one engine? Most cars never go more than two, but in 2012, BMW saw fit to slam three blowers into its 3.0-litre diesel block to yield the frankly insane M50d engine that churned out 381hp and 740Nm of torque. When fitted in the 5 Series, the engine had to come with all-wheel drive to ensure civilized deployment of its outputs.
But why stop at three?
At the Vienna Engine Symposium over the weekend, BMW confirmed long-suspected rumours by unveiling a new 3.0-litre inline-six diesel that has its outputs boosted by no less than four turbochargers.
In the absence of official press materials from BMW, reports from various international motoring websites indicated that the new quad-turbo straight-six will replace the existing tri-turbo six-pot and will debut in a new 750d xDrive variant of the current-generation G11 7 Series.
The same reports also revealed that the new engine generates maximum power of 394hp from 4,000 to 4,400rpm and twists out 760Nm from 2,000 to 3,000rpm. It is said that the engine has to be restricted from its full torque potential to protect the ZF 8HP automatic transmission paired to it.
Preliminary numbers for the 750d xDrive fitted with this engine are century sprint of 4.5 seconds and fuel consumption rated at 5.8 l/100km, a remarkable improvement from the current tri-turbo M550d xDrive’s already-impressive 6.3 l/100km. Top speed is electronically capped at 250km/h.