Chevrolet Impala gains stop-start, loses eAssist powertrain for 2015

Stop-start boosts the Impala\'s city mileage by one mpg.

General Motors has announced a pair of underhood changes to the Chevrolet Impala full-size sedan for the 2015 model year.

The eAssist mild-hybrid powertrain has been dropped, meaning the 2.5-liter four-cylinder and 3.6-liter V6 will be the only engine options moving forward.

Comprised of a 2.4-liter four-cylinder and a small electric motor, the eAssist setup was good for 182 horsepower and 25/35 city/highway mpg. However, only one percent of Impala buyers opted for eAssist, which was similarly deleted from the Malibu lineup last year.

The other news for 2015 comes in the form of a standard stop-start system for the Impala's 2.5-liter four. Stop-start, which saves fuel by shutting off the engine when the car is stationary and would otherwise be idling, will result in a fuel efficiency rating of 22/31 mpg - an increase of 1 mpg in the city.

GM says that revised motor mounts should help reduce the harshness typically associated with stop-start systems. A larger, heavy-duty starter motor was also fitted to cope with the added ignition cycles, and special software tuning will prevent stop-start from engaging if the car didn't reach 6 mph in its last start, thus making for a smoother driving experience in heavy traffic.

The 2015 Chevrolet Impala four-cylinder will start from $27,735 (including destination). The 3.6-liter V6 model, which carries over unchanged, commands $30,960.

Read more!