July 31, 2015 at 11:07 am by Robert Sorokanich
Turbos are hot right now. Seemingly every segment of the car industry has at least one turbo engine on offer; twin turbos, once the realm of exotic supercars, are now available on pickup trucks and family haulers. In 2012, BMW upped the ante with a triple-turbo inline-six diesel engine for the European market. But too much is never enough, apparently. Rumor has it, BMW’s readying a new diesel inline-six with four turbochargers.
This bit of unverified speculation comes to us from Autocar, and we’re taking it with a grain of turbo-salt, but this is the kind of rumor we can’t help but love. The British car magazine quotes “sources close to the German carmaker” saying that the alleged quadruple-boosted oil-burner will be a 3.0-liter inline-six packing “well over 400 hp and 590 lb-ft.” Which, damn.
As for those turbos themselves, theories vary. Autocar speculates that the new engine could be an evolution of the current tri-turbo 3.0-liter diesel, with “a small electrically driven turbocharger to increase low-end boost pressure and provide added punch.” Or, it could just be four conventional exhaust-driven turbos.
If this four-times-blown diesel engine does become a reality, rumor has it it’ll be destined for a new 7-series variant, the M750d, as well as all-wheel-drive M Performance diesel versions of the X5, X6, and X7. If the current triple-turbo diesel-powered M550d and X5 xDrive50d are any indication, this four-turbo mill probably isn’t destined for U.S. shores.
- Check Out BMW’s Crazy, Euro-Only Triple-Turbo Diesel Engine
- BMW 535d Diesel First Drive Review
- Tested: BMW 328d Diesel Sedan
Still, the thought of a quad-turbo engine that’s not made by Bugatti has our inner engineers all giddy. If BMW builds this four-turbo, 3.0-liter six-cylinder engine, it will catapult to the forefront on cylinders-per-turbo ratio (3:2), turbos-per-liter ratio (4:3), and pretty much every other turbo-related ratio we can think of.