“New and improved” is a slogan that companies often use to convince buyers to try their products. In the case of the three-liter inline six-cylinder turbodiesel that BMW has installed in the 2014 535d, it happens to be true: It is, indeed, new and improved—and is now recognized as such by Ward’s Auto, which has included it on its list of the 2014 World’s 10 Best Engines.
To determine the best engines in the twentieth year for Ward’s 10 Best Engines list, a panel of eight Ward’s Auto editors evaluated 44 engines or propulsion systems by driving them daily around metropolitan Detroit for a couple of months during the last part of 2013. The only eligible engines were all-new or significantly improved units found in current production models available in the U.S. in the first quarter of 2014. The panel scored each engine on the basis of horsepower, torque, technology, observed fuel economy, relative competitiveness, and noise, vibration and harshness characteristics.
BMW diesels are not new to the list. The previous, twin-turbo version won 10 Best status in 2009 and 2011. The new BMW diesel, code name N57, uses a single, variable-geometry turbocharger and coil-based, solenoid valve injectors that can deliver six separate injections per combustion stroke. More injections result in a quieter diesel.
Fuel economy has also improved. At 26/38 mpg, the 535d gets better mileage than BMW’s old diesel found in the 335d, even in a larger and heavier car. In actual driving, the Ward’s editors not only achieved the rated fuel mileage, but they averaged an exceptional 35 mpg driving in and around metropolitan Detroit. They commented that the BMW six achieved better mileage than some four-cylinder diesels they tested and even beat some luxury gasoline-electric hybrids.
Those of us who drive BMW diesels daily don’t mind the minor, non-intrusive chatter coming from under the hood as the engine idles. Some of us may even describe it as “charming.” The Ward’s editors claim that the new 535d doesn’t make such noise, and it’s the “all-around quietest diesel we’ve ever driven.”
Three of this year’s 10 Best were diesel engines, the other two coming from Chrysler and General Motors. The trophies for all the World’s 10 Best Engines will be presented on January 15 during the North American International Auto Show.—Scott Blazey