- #1
Thread Owner
This month, the new 2014 Chevrolet Impala will enter dealerships and if last year's sales figures are anything to go by, most of those Impalas will be sold with the new Ecotec four-cylinder engine technology with its improved power and better fuel economy. This year, Chevy has a surprise waiting, though: the new engines are quieter and even more fuel efficient than before.
Three engines are in the Impala's lineup for the 2014 model year (a V-6 and two 4-cylinders), but so far this year, most of Chevrolet's car buyers have opted for a four-cylinder engine and it's very likely that this trend towards higher efficiency, given the excellent output those small engines produce, will continue.
In the new Ecotec, the 2014 Chevrolet Impala finds a more fuel efficient, quieter option and the engineers at General Motors worked hard to make it that way. The 2.5-liter Ecotec puts out 196 horsepower, 186 lb-ft of torque, and features an all-new rocker arm setup that improves quieter and more precise valve lifting than in previous engines, especially at higher speeds and heavier loads.
The rocker arm switches between low and high lift intake cam profiles, being actuated by an oil control valve through a dual-feed, stationary hydraulic lash adjuster. This is the first time it's been used in low friction roller-type finger-rollover valvetrains in a gasoline engine. It's entirely controlled by the engine's computer, which tunes lift based on the engine load profile. This means less noise and better fuel economy - up to a full mile per gallon in some cases.
Read more http://www.torquenews.com/1080/how-...4-chevrolet-impala-got-quieter-more-efficient
