BMW N55 twin-scroll engine Secures Ward’s Auto Top 10 Engines spot

Ward’s 10 Best Engines in now on its 17th year of recognizing powertrains that set new benchmarks for a number of vehicle segments. BMW consistently secured a place in the top 10 again for the 3rd consecutive year. For 2007 and 2009, the BMW N54 twin-turbo engine took the limelight. But for this year, BMW’s N55 twin-scroll turbocharged engine takes its first win in the Wards 10 Best Engines.

Another engine from MINI also ranked in the top 10: the 1.6L turbocharged direct-injection I-4 developed by PSA Peugeot Citroen for BMW’s MINI Cooper S.

Wards tested the engines and scored them according to power, technology, observed fuel economy and noise, and vibration harshness. Here’s an excerpt of Ward’s review:

BMW’s well-regarded 3.0L N54 twin-turbocharged inline-6 earned Ward’s 10 Best Engines honors in 2007, 2008 and 2009. For 2011, the N55 I-6 in the 335i replaces the two compressors with a single twin-scroll turbocharger that saves weight, improves throttle response, boosts fuel efficiency (15% over the N54) and reduces friction, while decimating the notion of turbo lag.

Integrating the third-generation Valvetronic intake and Double-VANOS stepless variable valve timing, the 300-hp “Twin Power” N55 reaches its torque apex of 300 lb.-ft. (407 Nm) at a mere 1,200 rpm, propelling the 335i sedan with shocking ease. For drivability and smoothness, the N55 is unparalleled.

Another new engine on this year’s list is the 1.6L turbocharged direct-injection I-4 that packs a mighty punch in the Mini Cooper S. With a specific output of 113 hp/L, this package quickly rose to the top of a crowded field of new small-displacement 4-cyl. engines in this year’s competition.

The latest “Prince” engine in the Cooper S is assembled for BMW by PSA Peugeot Citroen in Douvrin, France, and integrates BMW’s excellent Valvetronic fully variable valve timing system, which enhances power and fuel efficiency. Driven hard, this prince of an engine still musters better than 34 mpg (6.9 L/100 km) during our test drive.

Ward’s Auto Top 10 Engines for this year are as follows:

3.0L TFSI Supercharged DOHC V-6 (Audi S4)
3.0L N55 Turbocharged DOHC I-6 (BMW 335i)
1.6L Turbocharged DOHC I-4 (Mini Cooper S)
3.6L Pentastar DOHC V-6 (Dodge Avenger)
5.0L DOHC V-8 (Ford Mustang GT)
1.4L DOHC I-4/111kW Drive Motor (Chevrolet Volt)
5.0L Tau DOHC V-8 (Hyundai Genesis)
80kW AC Synchronous Electric Motor (Nissan Leaf)
2.0L DOHC I-4 Turbodiesel (Volkswagen Jetta TDI)
3.0L Turbocharged DOHC I-6 (Volvo S60

Source: Wards