2012 Mazda3 Skyactiv

Without much effort, we can alphabetically list the Chevrolet Cruze, Ford Focus, Honda Civic, Hyundai Elantra, Mazda3 and Toyota Corolla. Sticker prices, fuel economy numbers and warranty terms are objective and indubitable. Driving dynamics, styling and passenger comfort, in sharp contrast, are subjective. Enter the new 2012 Mazda3 Skyactiv.

We're supposed to be pedaling our way to 40 mpg in the 2012 Mazda 3. Fun driving ruins fuel economy. As tougher fuel-efficiency standards loom, Mazda is dealing with it, too. The most efficient 2011 Mazda 3 was rated just at 25 city/33 highway mpg.

Fuel mileage climbs as high as 28 city/40 highway. Mazda is still offering its older, port-injected, 148-hp 2.0-liter MZR engine as a less expensive alternative on base i and i Sport models, while the 167-hp 2.5-liter MZR engine remains on s models for those of you seeking more torque (it's rated for 166 lb-ft at 4,000 rpm).

High compression is the key to the Skyactiv-G engine's combination of usable performance and excellent fuel economy. "The 4-2-1 exhaust manifold is big," Kenichiro Saruwatari, chief engineer for the Mazda 3, told us, "so we cannot package it in the current Mazda 3 chassis — it would touch the dashboard."

A modernized injection system on the Skyactiv-G engine squirts fuel into the combustion chambers at higher pressure than on the automaker's only other D.I. engine — the 2.3-liter turbo on the Mazdaspeed 3.

You'll also note that the new engine is undersquare, with an 83.5mm cylinder-bore diameter and a 91.2mm stroke, compared to the oversquare 2.0-liter MZR engine (87.5mm bore diameter, 83.1mm stroke). Mazda also looked for every way possible to reduce friction on the Skyactiv-G engine.

When we get into our 2012 Mazda 3 i Touring Sedan, we're assured it really is running on 87 octane. Our car has the new six-speed manual, which is Mazda's first totally new manual gearbox since the 1980s.

Mazda conservatively estimates that an automatic-equipped Mazda 3 with the Skyactiv-G engine will hit 60 mph in 9.6 seconds — significantly quicker than an automatic-equipped car with the 2.0-liter MZR engine (10.3 seconds). A manual-equipped Skyactiv-G car should be even quicker.
Even with only 155 hp, the Mazda 3 is a purer sport compact than some other cars with 50-100 hp more.

The 2012 Mazda 3 is also an excellent value. Although the 2.0-liter Skyactiv-G will be the volume engine on the 2012 Mazda 3, the automaker isn't expecting an overall increase in Mazda 3 sales, which usually hover around 100,000 units per year.