General Motors 2.0L Turbocharged DOHC I-4

When the product bosses considered powertrain options for the all-new ’12 Buick Regal GS, there were factions within General Motors pushing for the turbocharged 2.8L V-6, which won a Ward’s 10 Best Engines award in 2006 for its application in the Saab 9-3 Aero.

But others within GM argued convincingly that the V-6, although powerful, would deliver mediocre fuel economy and add too much weight to the front end of a car intended to be nimble.

These voices prevailed by pushing for a much smaller but potent engine that fits with the industry’s smaller-is-better mindset, while delivering solid fuel economy.

The decision pays off handsomely as the High-Output variant of the direct-injection Ecotec 2.0L turbocharged 4-cyl, with its outrageous specific output of 135 hp/L, powers its way onto the 2012 Ward’s 10 Best Engines list.

With 270 hp and 295 lb.-ft. (400 Nm) of torque, this mighty mill is the most power-dense engine ever certified by the Society of Automotive Engineers.

The High-Output Ecotec is one of three 2.0L turbo engines making this year’s list, and it trumps them all on the power scale, even the unit in the more-expensive BMW Z4 and 528i.

“This engine charges like an angry water buffalo when you get the revs up,” WardsAuto editor Drew Winter writes on his Regal GS scoresheet. “And yet, it’s silky smooth. It’s hard to believe this is similar to what was in the Pontiac Solstice and Saturn Sky.”

Yes, GM launched a port-injected version of this Ecotec I-4 five years ago in the 2-seat roadsters.

A year later, direct injection was integrated, and in 2008 the engine appeared in the Chevy HHR SS. Along the way, the package fundamentally did not change, achieving the same compression ratio of 9.2:1 and using a similar twin-scroll turbocharger designed to mitigate turbo lag.

In these earlier applications, the Ecotec made loads of power but also too much racket. The Regal GS surges even harder but sounds terrific doing so.

Gone is the waffly exhaust drone of the earlier versions. Bonuses all around for the designers and engineers who encapsulated the noise and filled our ears with such a catchy tune. And after all these years, we thought Buick couldn’t even sing.

For now, this engine will be secure in its applications in the Regal and the upcoming Buick Verano turbo.

But future prospects become hazy as GM announces in December plans for what sounds like the next generation of the Ecotec 2.0L turbo, which arrives in the ’13 Cadillac ATS compact luxury sedan, soon to be revealed at the North American International Auto Show in Detroit and beginning production in summer. The Chevy Malibu also may get the updated 2.0L.

Technical details will follow, but the direct-injection engine in the ATS  is expected to produce the same 135 hp/L as the current high-output Ecotec turbo, with improved durability, refinement and friction reduction.

An increased compression ratio also should translate into better fuel economy, and the torque peak of 260 lb.-ft. (353 Nm) is expected to arrive lower in the power band, by 1,500 rpm.

So even though the Regal GS takes the trophy this year, the Cadillac ATS will vie for its own next year.

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