BMW's New Diesel Engine Has Four Friggin' Turbos

Diesel engines may be under a lot of scrutiny right now thanks to the whole VW thing, but that doesn’t mean innovation stops. Only a few weeks ago Audi revealed its 4.0-litre V8 TDI SQ7 with electric compressor technology, and now BMW has released a similarly punchy 3.0-litre oil-burner.

It’s a replacement for the old triple-turbocharged unit (pictured above), only this time BMW has upped the ante and added a fourth turbocharger. Yep, quad-turbocharged - not something you’ll see terribly often outside of a Bugatti Veyron.

Details are still fairly thin on the ground, but according to Bimmerpost, we’re looking at 389bhp and 561lb ft of torque. It could be good for more twist than that, but apparently the ZF eight-speed is the limiting factor here: it’s simply not able to take any more torque.

The old triple-turbo ‘N57S’ unit had a small blower for low revs, a larger turbocharger that kicked in at the mid-range, and another smaller one for higher engine speeds. What the new engine (designated B57) does is replace the larger turbocharger with a pair of smaller units, giving a quartet of little turbos. As well as upping power the new quad-turbo system is responsible for a five per cent drop in fuel consumption.

The engine will first appear in the BMW 750d xDrive, where it’ll propel you from 0-60mph in just 4.5 seconds. Although we’re holding out hope for the engine to appear in a successor to the M550d…