When we last tested the Chevrolet Impala, it landed right at the top of our Ratings charts, outscored only by the Tesla Model S. Now the Impala is available in three new versions, a conventional 2.5-liter four-cylinder, a 2.4-liter four-cylinder mild hybrid, and a new bi-fuel natural-gas V6.
We had the chance to try out the conventional four-cylinder Impala to see if downsizing the engine had any detrimental effect. In short, we found it didn’t. The Impala is still a smooth operator, with no objectionable increase in engine noise or decrease in refinement. This engine has to work pretty hard here, but it’s well isolated, even more so than in the Chevrolet Malibu and outdated Equinox. Prices start at $26,860.
The second engine choice is the Impala Eco, which GM calls a hybrid, though it barely qualifies. This variation uses a mild belt-alternator-starter hybrid system. We’ve sampled this powertrain in the Impala’s twin, the lower-scoring Buick LaCrosse, and in the former Malibu Eco. In both cases, we thought it didn’t return the mileage you might expect from a “hybrid.” We recorded 26 mpg overall in the LaCrosse and 29 mpg in the Malibu. It works seamlessly enough, but the battery takes up a fair amount of trunk space. It sells for $29,135, or about $10,000 less than our original fully loaded V6 test car.
Though it’s likely to sell the least, the biggest news may be the introduction of a bi-fuel version of the Impala that can run on either compressed natural gas or gasoline. Using the same 3.6-liter V6 engine we tested in the Impala, the bi-fuel version has two tanks; the cylindrical natural-gas tank occupies much of the trunk space. The CNG tank, which holds the equivalent of 7.8 gallons of gasoline, is expected to offer about 150 city miles of range on natural gas. The driver can select which fuel the car runs on via a dashboard switch, or, if the CNG tank runs dry, the car will automatically switch over to gasoline. The CNG system is added after the car is built, but the bi-fuel Impala is sold through Chevrolet dealers and is eligible for Chevrolet’s full three-year, 36,000-mile bumper-to-bumper and 100,000-mile powertrain warranties. It will be available to consumer and fleet customers in late 2014 and will list for $38,210—almost matching the price of our loaded Impala LTZ2 test car.
The bi-fuel Impala expands options for buyers who want to drive on natural gas. Chevrolet, Ford, and Ram also offer bi-fuel pickups that join the CNG-only Civic Natural Gas, which was the only natural-gas powered car on the mass market for years.
–Eric Evarts
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