Like never before, the 19th annual Ward’s 10 Best Engines competition illustrates the break-neck pace of powertrain development as auto makers attempt to one-up their rivals.

The 2012 contest kept WardsAuto editors busy evaluating 34 engines. But this year, 41 engines are being evaluated, and four of those will be driven in multiple vehicles that highlight new applications or the recent availability of stop/start technology or new transmissions.

Even more telling are the notable upgrades to engines that were named winners less than a year ago.

Last year, Hyundai impressed us with a stout, sophisticated and affordable direct-injection 138-hp 1.6L 4-cyl. in the Accent subcompact. This year, that engine arrives with a turbocharger, boosting output to 201 hp, for an outlandish specific output of 126 hp/L in the Veloster Turbo.

Last year, a winning engine from General Motors delivered an even higher specific output of 135 hp/L. Already, that 2.0L turbocharged 4-cyl. in the Buick Regal GS is being phased out in favor of an engine the same size but with more active cam phasing, better sound attenuation and increased efficiency.

The specific output of this Ecotec 2.0L turbo will take yet another step up, to 136 hp/L, in the new Cadillac ATS compact luxury car.

Mazda won last year with its 155-hp Skyactiv 2.0L 4-cyl. in the Mazda3, which boasted an unusually high compression ratio of 12.0:1.

This year, that same engine is being evaluated in the CX-5 cross/utility vehicle, whose larger engine bay allows for an unwieldy 4-2-1 exhaust manifold that enables an even more efficient 13.0:1 compression ratio, while running on 87-octane fuel. And more Skyactiv powertrain goodies are on tap for next year.

Last year, Ford won two Ward’s 10 Best Engines awards, including one for the 2.0L EcoBoost 4-cyl. that made 240 hp in the Ford Edge CUV.

This year, that same engine also sees duty in the Ford Explorer and new for ’13 Fusion, and it is shockingly capable in the fullsize Taurus sedan.

WardsAuto editors are testing this mighty powerplant in the track-friendly Focus ST, in which it produces an additional 12 hp while boosting city fuel economy 10%.

But don’t think for a minute auto makers are giving up on displacement. Ford’s excellent 5.0L DOHC 5.0L V-8 in the Mustang Boss 302 is back in the hunt, seeking its third straight win.

Also in the competition is Ford’s tire-shredding 662-hp Shelby GT500 powered by a 5.8L supercharged V-8 and GM’s 580-hp Chevrolet Camaro ZL1 motivated by a 6.2L supercharged OHV V-8.

If GM’s 6.2L doesn’t make the list in 2013, a new version will be in the running for 2014 as the clean-sheet, fifth-generation small-block V-8 arrives in the new Chevrolet Corvette, and in GM pickup trucks, to preserve the legacy of pushrods and 2-valves-per-cylinder in an industry that migrated long ago to overhead-cam and multi-valve architectures.

Still, this year’s competition leans inexorably toward downsizing. Featured are three V-8s, 10 6-cyl. and 24 4-cyl. engines, including six hybrids.

Two 6-cyl. hybrids also join the fray: BMW’s ActiveHybrid 3, which features the award-winning N55 turbocharged 3.0L I-6, and the Infiniti M35h, which earned 2012 Ward’s 10 Best Engines honors.

Although auto makers claim enthusiasm for diesels in the U.S. market, only one contender is in the running this year: Audi’s 3.0L V-6 in the Q7 TDI CUV. Next year’s competition should see new diesels from GM, Chrysler, Mazda and perhaps others.

The ultimate fuel sippers are back in the game this year as well, as battery-electric versions of the Honda Fit, Ford Focus and Mitsubishi i attempt to prove their worth against internal-combustion powerplants. No EVs made the list in 2012, but the Nissan Leaf and Chevrolet Volt extended-range EV both won honors in 2011.

WardsAuto editors are driving the 41 engines in production vehicles in metro Detroit during their routine commutes in October and November, paying close attention to horsepower/torque; noise, vibration and harshness; drivability; packaging; fuel economy; technical relevance; and specs.

To be eligible, an engine must be all-new or significantly improved and be available in a production vehicle that will be on sale by first-quarter 2013. To keep the competition in the realm of mainstream vehicles, base price is capped at $55,000.

The winners will be announced in December, and auto makers will receive their trophies at an awards ceremony to be held during the North American International Auto Show in Detroit.

tmurphy@wardsauto.com

2013 Ward’s 10 Best Engines Nominees

Acura ILX / 2.0L I-4

*Audi S5 / 3.0L supercharged V-6

*BMW 135is / 3.0L TwinPower N55 I-6

*BMW 328i / 2.0L TwinPower N20 I-4

BMW ActiveHybrid 3 / 3.0L N55 I-6 HEV

Dodge Dart / 2.0L Tigershark I-4

*Ram 1500 / 3.6L Pentastar V-6

Fiat 500 Abarth / 1.4L MultiAir turbocharged I-4

Ford Fusion / 1.6L EcoBoost I-4

*Ford Focus ST / 2.0L EcoBoost I-4

Ford Focus EV / 23 kWh battery electric

Ford Fusion Hybrid / 2.0L I-4

Ford C-Max Energi / 2.0L I-4 PHEV

*Ford Mustang Boss 302 / 5.0L V-8

Ford Shelby GT500 / 5.8L supercharged V-8

Cadillac ATS / 2.0L turbocharged I-4

Cadillac ATS / 2.5L DI I-4

Cadillac ATS / 3.6L DI V-6

Chevrolet Spark / 1.2L 4-cyl.

Chevrolet Camaro ZL1 / LSA 6.2L supercharged V-8       

Honda Accord / 2.0L PHEV

Honda Accord Sport / 2.4L DI I-4

Honda Accord Touring / 3.5L V-6

Honda Fit EV / 20 kWh battery electric

*Hyundai Accent / 1.6L DI I-4

Hyundai Veloster Turbo / 1.6L turbocharged I-4

Hyundai Genesis Coupe / 2.0L turbocharged I-4

Hyundai Azera / 3.3L DI V-6

*Infiniti M35h / 3.5L V-6 HEV

Jaguar XF / 3.0L supercharged V-6

* Mazda CX-5 / 2.0L Skyactiv I-4

Mitsubishi “i” / 16 kWh battery electric

Nissan Sentra / 1.8L I-4

Nissan Altima / 2.5L I-4

Subaru BRZ / 2.0L FA H-4 

Subaru Outback / 2.5L FB H-4

Toyota Prius c / 1.5L I-4 HEV

Toyota Prius PHEV / 1.8L I-4 HEV

Volkswagen Jetta Hybrid / 1.4L turbocharged I-4 HEV

Volvo S60 T5 / 2.5L turbocharged I-5

*Denotes returning winners.

(10th returning winner from 2012 was Buick Regal GS’ 2.0L turbocharged I-4, which has been significantly overhauled for new Cadillac ATS and Chevrolet Malibu.)