Subaru FB engine

The Subaru FB engine is the third generation of Subaru gasoline boxer-4 engine, announced on 23 September 2010 as the successor to the EJ series, which had followed the EA of 1966. Subaru increased the piston stroke and reduced the bore, from 99.5 to 94 mm in the largest version, to cut emissions and improve fuel economy while broadening the torque output. The FB has an all-new block and head with dual overhead cams, variable valve timing on intake and exhaust that Subaru calls AVCS, and a timing chain in place of the belt. Subaru claims a 28 percent cut in friction losses and a 10 percent fuel economy gain. It is built at the Gunma Oizumi plant in 1.6, 2.0 and 2.5 litre sizes, naturally aspirated, turbocharged, direct-injected and hybrid. In 2020 the CB18 engine was introduced to succeed it in several applications.