A turbocharger can significantly increase an engine’s horsepower without adding a lot of weight, which is partly why so many automakers today are adding turbos to their lineups. Turbocharging allows vehicles to use smaller engines and achieve greater fuel economy without sacrificing performance.
A turbocharger works by using exhaust gas to spin a turbine which in turn powers a pump that sucks in additional air that is directed back into the engine for an added boost. One of the biggest downsides of a turbocharger is that it can take time to wind up and apply the boost, a problem called turbo lag.
Lag problems are sometimes addressed through a twin sequential turbocharger system, in which one turbo handles low-RPM conditions and another kicks in for high-RPM conditions. In 2012, BMW introduced a tri-turbo system for the European market.
The third turbocharger awakens in the upper rev limits to achieve peak performance, but apparently three were still not enough.
The German automaker has announced its newest engine: the 3.0-liter inline 6-cylinder quad-turbo diesel.
Munich’s newest diesel pumps out 394 hp and 561 lb-ft of torque, with all of that torque on tap at just over 2,000 rpm. All of this is achieved through multistage turbocharging; two high-pressure turbos and two low-pressure turbos take care of low-end torque and high-end torque, also taking advantage of better charge-air cooling.
For the uninitiated, 561 lb-ft of torque at just 2,000 revolutions per minute best translates like this: It’s hold-onto-your-shorts fast.
We hope this engine will make it the U.S., but in the meantime we can expect to see the new quad-turbo engine in the BMW 750d xDrive in Europe, where it will be paired with an 8-speed automatic transmission that will allow for sprints from 0 to 60 in just 4.5 seconds.
Keep in mind that the 7 Series is BMW’s biggest sedan and can weigh well over 4,000 pounds. The fact that a 6-cylinder can propel that much weight so quickly speaks volumes to the power of turbochargers, and proves that three were just not enough.
Will your next car be turbocharged?