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Very slick: Automakers strive to reduce engine friction - NWautos
General Motors has quantified the overall friction reduction for three of its four-cylinder engines. The 2007 2.4-liter four-cylinder generated 46 percent less friction in low-speed driving than GM's 2-liter four-cylinder of the early 1980s, despite having more valves, a more complex camshaft drive and a pair of counterbalancer shafts. Friction reduction alone resulted in about 7 percent better fuel economy over that 24-year period.
In the new 2.5-liter four-cylinder that will power the 2013 Chevrolet Malibu, friction has been cut another 16 percent, resulting in a 2 percent engine efficiency gain compared with the 2007 2.4-liter.
Each engine developed more power per liter than its predecessor, doing more