Posted By RichC on October 11, 2010
I’ve always been impressed with the durable Subaru boxer engine and look forward to someday seeing the diesel version here in North America. For now, a new, more fuel efficient gasoline model is on it’s way in the 2011 Forester.
The horizontally opposed engine has been a signature mainstay of Subaru vehicles since 1966. Last redone in 1989, the automaker completely remade its well-proven workhorse for 2011, incorporating a comprehensive series of changes that enhances overall performance, lowers emissions and generates roughly a 10-percent bump in fuel economy. Initially available in 2.0- and 2.5-liter four-cylinder incarnations, this all-new engine family is set to become the primary motivator for Subarus worldwide. Its first U.S. application will be in 2.5-liter form under the hood of the 2011 Subaru Forester that goes on sale later this fall.
A showcase for Subaru’s technical expertise in the boxer engine design arena, this new-gen flat-four is based around a more compact cylinder design that features a smaller bore and far longer stroke dimensions, a combo that fosters better combustion efficiency and improves mid-range torque. Other key technologies include a new Active Valve Control System (AVCS) on both intake and exhaust valves, special efficiency-optimizing partitions within the intake ports, individualized cooling circuits for the block and head plus a bump in compression ratio. Complementing those feature are a more extensive use of even lighter-weight internal components and a new oil pump that cuts friction loss by nearly 30 percent.
This new Subaru engine family is being manufactured at an equally new, state-of-the art facility outside of Tokyo. In making the announcement, Subaru’s parent company, Fuji Heavy Industries, stressed that the new boxer-four was created with both expandability and the potential to for future upgrades in mind, on both the environmental and performance fronts.