Tiny Turbos, Big-Displacement Mills Bookend GM’s 10 Best Engines Showcase

General Motors claims two spots on our 2016 Wards 10 Best Engines list, but two more score remarkably close out of a crop of seven total nominees under consideration from the automaker.

Winners are the all-new range-extended electric propulsion system in the ’16 Chevrolet Volt and the totally overhauled 3.6L V-6 tested in the Chevrolet Camaro and the Cadillac ATS. Both second-generation powertrains win high praise for significant improvements and superior performance.

Close contenders are two engines that bookend GM’s powerplant showcase: the twin-turbo 3.6L V-6 in the Cadillac ATS-V and the turbocharged 1.5L I-4 in the Chevy Malibu. Others earning consideration include the 6.2L V-8 in the Camaro SS, the all-new 2.8L turbodiesel I-4 in the Chevy Colorado/GMC Canyon midsize pickups and the 3.6L CNG V-6 in the Chevy Impala.

It’s a tough call to leave out a wicked engine like the ATS-V’s twin-turbo V-6. It makes 464 hp at 5,850 rpm and 445 lb.-ft. (603 Nm) of torque at just 3,500 rpm.

That works out to a strong specific output of 130 hp/L, while posting fuel economy in the 22-mpg (10.7 L/100 km) range in our real-world driving. The BMW M3 does slightly better but at a substantially higher price compared to our test car ($60,465 base price, just under our $61,000 base-price cap).

Cost is the ATS-V’s Achilles heel in this case, along with the fact the engine is based on GM’s outgoing 3.6L V-6. They’ve pushed this engine to the limit; we can’t wait to see what happens when the same atmospherics and engineering extras are applied to the all-new 3.6L V-6.

At the opposite end, the Malibu’s diminutive 1.5L turbo I-4 represents the future of GM propulsion, starting with its starring role as the Volt’s new engine (in non-turbo form) and as the primary mover in Chevy’s bread-and-butter small sedan.

In the 3,100-lb. (1,406-kg) Malibu, the turbo engine’s 184 lb.-ft. (249 Nm) of torque and its impressive 30-35 mpg (7.8-6.7 L/100 km) draws rave reviews, along with its relative quiet even at wide-open throttle. With just a little more refinement, this engine is a winner.

Turbodiesel Needs More Work

We are somewhat dismayed at the relatively rough integration of the much-anticipated 2.8L turbodiesel I-4 in the Colorado pickup we tested. The diesel’s high $6,625 markup also gives pause.

Editors love the engine’s rip-roaring 369 lb.-ft. (500 Nm) of torque, towing capability and its observed 28 mpg (8.4 L/100 km) in around-town driving, but are put off by abrupt throttle response and noise and vibration from idle to wide-open throttle.

Overall, editors applaud GM’s effort, and we hope improvements down the road will make this engine a worthy competitor to the more-refined Ram 1500 EcoDiesel.

Two more bookends of GM’s powertrain family complete the contenders, the powerful LT1 V-8 in the Camaro SS and the CNG-powered 3.6L V-6 in the Impala that impresses mostly by being unremarkable.

In the Camaro SS, the 6.2L V-8 punches out 455 hp and 455 lb.-ft. (617 Nm) of torque – more than enough to break loose the meaty rear rubber, even in third gear. But the high-revving Ferrari-like wail of the flat-plane crank V-8 in Ford’s Shelby GT350 short-circuited the LT1’s bid for a 10 Best Engines three-peat.

We find a lot to like about the Impala CNG V-6, whether running on compressed natural gas or regular unleaded (a push-button allows easy fuel selection). But other than fleet users with easy access to CNG, we’re not sure there’s much advantage to the alternative fuel system, especially when fuel economy drops from 22.6 mpg (10.4 L/110 km) on unleaded to just 16 mpg-e (14.7 L/100 km) running on CNG.

Overall, it’s evident GM engineers aren’t resting in the race to build some of the world’s best powertrains, from track-ready machines to workaday engines to futuristic alternative-propulsion vehicles.

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