BMW rumoured to be working on quad-turbo diesel 400-hp engine

Twin-turbo and even tri-diesel diesel setups are so passé nowadays, and BMW knows it, too. A new report from the folks over at Autocar says BMW is finalizing an all-new quad-turbo, straight-six, diesel engine for use in a number of high-end flagship models. This information comes to Autocar by way of a source close to BMW.

The report says the performance oriented quad-turbo diesel will see its debut in the new 7 Series M750d in 2016, because the existing tri-turbo diesel setup isn’t complex or crazy enough. The source claims it will have a displacement of 3L and push out over 400 hp and 590 lb-ft of torque.

As far as I’m concerned, this is all speculation and Internet rumours, but the source suggests the new engine setup will build upon the existing 376-hp and 545-lb-ft tri-turbo unit used in the M550d and X5 xDrive50d M Performance (Europe only, of course) by adding a small electrically driven turbocharger to increase low-end boost pressure and provide added punch.

Technically, that’s not a true quad-turbo setup in my opinion. The electrically driven turbocharger is more of a booster than a part of the actual powertrain, in my opinion.

Though, alternatively, if a fourth conventional turbocharger was to be added inline or in sequence, that would be more of a true quad-turbo setup.

After its debut in the M750d, the new quad-turbo setup is set to appear in the X5 XDrive50d, X6 xDrive50d, and X7 xDrive50d.

What say you, oh ye autophiles? Is this wild Internet speculation or do you think we’ll actually see a mass produced quad-turbo setup from BMW? Either way, we’re no more likely to see a quad-turbo unit over in Canada than we were the tri-turbo setup.