2017 Wards 10 Best Engines: Falling in Love With 6-Cyl. Turbos

TRANSCRIPT

It’s a great year for turbocharged 6-cyl. gasoline engines. Five new ones have been torturing the concrete in and around Southfield, MI, in recent weeks as WardsAuto editors wrap up test drives for the 2017 Wards 10 Best Engines competition.

BMW and Ford each have two stout turbo-6s in the hunt this year, while Infiniti has one. There’s a common thread that binds all five together: They are smooth, extremely refined, reasonably fuel-efficient and dishing up enough horsepower and torque to question the long-term viability of V-8s.

Let’s start with two of these engines that are close enough in spec and demeanor to consider them twins separated at birth. One is in the Lincoln MKZ and Continental, the other in the Infiniti Q50 sedan and Q60 coupe. Both V-6s have twin turbochargers, nearly identical bore and stroke, measure 3.0L in displacement and are rated at 400 hp, which gives them both an impressive 133 hp/L.

Both pull duty in all-wheel-drive luxury cars, so the MKZ and Q50 are fairly docile and quiet when tooling around town. But get out on the back roads, crack open the throttle and both these engines pull hard and love to rev, capable of a 60-mph (97 km/h) sprint in less than 5 seconds.

The Ford engine has the edge with 400 lb.-ft. (542 Nm) of torque – that’s 50 more than the Infiniti. But Infiniti’s “VR” engine has the higher (10.3:1) compression ratio, which contributes to the better combined fuel economy rating of 22 mpg (10.7 L/100 km), which is in line with our testing.

Clearly, Lincoln and Infiniti want to fight BMW, whose turbocharged inline 6-cyl. engines seem to get better every year.

The Bavarians have two new or significantly improved 3.0L turbos this year, both in versions of the 2-Series coupe. There’s the BMW M240i with the newer B58 engine, which won a Wards 10 Best Engines trophy last year, as well as the M2, powered by a modified version of the excellent N55 turbo-6, which won 10 Best Engines honors in 2011, ’12 and ’13.

The engines hail from two different engine families, but they both use twin-scroll turbochargers. The N55 in the M2 makes more horsepower (365), while the B58 in the M240i makes more torque (369 lb.-ft. [500 Nm]). However, the M2 has an overboost feature that cranks up torque from 343 lb.-ft. (465 Nm) to 369. The N55 has a wider bore but shorter stroke compared with the B58.

These two BMWs are lighter than both the Continental and Q50, so they’re actually faster. The M2 can sprint to 60 mph in 4.1 seconds, a bit faster than the M240i. As expected, the M240i is the more fuel-efficient, rated at 25 mpg (9.4 L/100 km) combined, which is in line with our testing.

The fifth turbocharged 6-cyl. arrives in the Ford F-150 pickup with enough stump-pulling goodness to out-torque the excellent 5.0L V-8 by a whopping 83 lb.-ft. (113 Nm). Tied to a new 10-speed automatic transmission, this second-generation EcoBoost V-6 makes 375 hp and benefits from more boost, higher compression, standard stop/start functionality and reductions in weight, noise and friction.

Pickup trucks have gotten awfully expensive, and this engine carries a $2,095 premium. But don’t despair: The EcoBoost V-6 is available in a regular-cab F-150 for under $30,000.

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