Subaru FB engine

Subaru FB engine
Overview
Manufacturer	Subaru
Production	2010–present
Layout
Configuration	Flat-4
Displacement	1.6 L (1,599 cc) 2.0 L (1,995 cc) 2.5 L (2,498 cc)
Cylinder bore	78.8 mm (3.10 in) (FB16) 84 mm (3.31 in) (FB20) 94 mm (3.7 in) (FB25)
Piston stroke	82 mm (3.23 in) (FB16) 90 mm (3.54 in) (FB20 & FB25)
Valvetrain	DOHC 4 valves x cyl. with AVCS
Compression ratio	10.5:1, 11.0:1, 12.5:1
Combustion
Turbocharger	Optional
Fuel system	Fuel injection
Fuel type	Gasoline
Cooling system	Water-cooled
Output
Power output	84–136 kW (114–185 PS; 113–182 hp)
Torque output	15.3–25.5 kg⋅m (150–250 N⋅m; 111–184 lbf⋅ft)
Chronology
Predecessor	EJ
Successor	FA, CB

The Subaru FB engine is the third and current generation of gasoline boxer-4 engine used in Subaru automobiles, and was announced on 23 September 2010.^[1] It follows the previous generation EJ-series engine which was introduced in 1989 and the first generation EA-series which was introduced in 1966. By increasing piston stroke and decreasing piston bore, Subaru aimed to reduce emissions and improve fuel economy, while increasing and broadening torque output compared to the EJ-series.

The Subaru FA engine series was derived later from the FB, but the two engine families share only a few common parts. In 2020, Subaru introduced the CB18 engine with improved efficiency to succeed the FB in several applications.