While sheetmetal changes, trim, chrome brightwork, and other minor details might come and go almost every model year, it's relatively rare for any new vehicle to get an entirely new powertrain. But that's the case with the 2012 Mazda3; even though the mid-cycle changes it gets for 2012 are quite subtle, nearly everything under the hood is new.
If you get one of the Mazda3 models with Skyactiv, that is. Under Mazda's wide-ranging engineering initiative, which we've reported on extensively, the automaker has reengineered all of its core components—including engines, transmissions, and body structure. While the 2012 Mazda3 doesn't get the new body structure improvements, in mid-level Mazda3 i Touring and Grand Touring models it gets the all-new Sky-G engine and all-new Skyactiv manual or automatic transmissions—to achieve up to 40 mpg highway.
According to Mazda's North American vehicle development engineer and R&D chief Dave Coleman, the new automatic transmission is the first complete redesign since the 1980s; although it's seen added gears and some significant iterations and engineering improvements over the years—like added gears—the five-speed automatic that's still used throughout much of the Mazda lineup (and to be eventually replaced by the Skyactiv unit) dates back to the 1983 Mazda 626. Meanwhile, the all-new six-speed manual gearbox that makes its debut in Skyactive-equipped 2012 Mazda3 models is the first clean-slate unit since in more than 30 years; the previous gearbox, through various improvements, launched in the 1980 Mazda 323.
Mazda's MZR engine, otherwise offered in the base Mazda3 i SV and Sport models—as well as, in 2.5-liter form, in the sportier 's' models—only dates back about ten years. But Mazda is moving on, in favor of the new Sky-G engine, which combines direct injection, electronically variable valve timing, and a high-compression design with 'volcano' (domed and cupped) pistons. The automaker has also redesigned all the ancillaries, like oil and water pumps, and the exhaust, to minimize heat and pumping losses.
So if you want the latest—without any real loss in 'zoom-zoom,' as we found in our First Drive of the 2012 Mazda3 this past week—you should look for those Skyactiv models.
For the full story about the Mazda3, including all of its engines and trims, see our full review of the 2012 Mazda3.