List of Subaru engines

It is not compliant with Japanese Government regulations concerning displacement of kei cars with a current maximum limit of 660 cc.

Subaru unveiled the world's first boxer diesel engine to be fitted in a passenger car at the Geneva Auto Show in 2007.

The EE20 shares a bore pitch dimension and assembly line with the EZ30 at the Ooizumi Factory; compared to the contemporaneous gasoline EJ20, which has a similar displacement, the EE20 is 61.3 mm (2.41 in) shorter.

[7][5] For the Legacy 2.0D, Subaru claimed consumption improved by 15 to 20% (ranging from 6.4 to 5.6 L/100 km (37 to 42 mpg‑US)) and that CO2 emissions fell from 202 to 148 g/km (0.72 to 0.53 lb/mi) compared to the similar model with a gasoline engine.

[7][8] Fuji Heavy Industries (FHI) spent three years starting in fall 2005 developing the EE20 after concluding the marque needed a diesel engine to compete in Europe.

[8] Details about the engine were first released in February 2008,[5] after an additional preview at Frankfurt in 2007,[9] and an official announcement of applications was made at Geneva in March 2008.

[5] In September 2008, FHI announced the EE20 would be available as a slightly modified variant (the diesel particulate filter was now closed) in Forester and Impreza models sold in Europe starting that fall.

[16] At Geneva 2013, the diesel boxer was combined with three electric motors to form the hybrid powertrain of the Subaru VIZIV Concept.

[18] In 2016, citing increasingly stringent emissions standards, the project manager for the Impreza stated that further development of the EE20 had been halted.

[19] In September 2017, Subaru announced production of diesel automobiles would end by 2020; at the time, sales were approximately 15,000 diesel-powered cars annually in Europe and Australia.

[20] At Geneva in March 2018, Subaru UK confirmed its parent company's plans to discontinue diesel production, but had enough stock on hand to meet projected demand through the end of 2018.

It was designed from scratch with five main crankshaft bearings and four valves per cylinder and can be either SOHC or DOHC and one timing belt.

The FB is only marginally heavier and has similar exterior dimensions compared to an EJ engine of equivalent displacement.

[26] Direct Injection was added to FB engines used in the 2017 Impreza, 2018 Crosstrek, 2019 Forester and the 2020 Legacy and Outback models.

Subaru claims a 28-percent reduction in friction losses, mainly due to lighter pistons and connecting rods.

[31] Compared to the FB16 used in the previous generation of the Levorg, the CB18 offers decreased fuel consumption (16.6 km/L (39 mpg‑US) for the CB18 and 16.0 km/L (38 mpg‑US) for the FB16, both using the JC08 mode) and increased torque (300 N⋅m (31 kg⋅m; 220 lb⋅ft) for the CB18 and 250 N⋅m (25 kg⋅m; 180 lb⋅ft) for the FB16).

[32] For the first time in a Subaru engine, the centerlines of the cylinder bores do not intersect with the crankshaft axis to reduce friction during the piston downstroke; instead, there is a crank offset of 8 mm (0.31 in).

Overall thermal efficiency is 40% due to the adoption of lean-burn combustion with an excess air ratio (λ) of 2.