Subaru FA boxer engines 

The FA engine first produced since 2012 was developed from the FB engine. It is a Petrol (gasoline) flat Water-cooled boxer 4 engine with DOHC 4 valves per cyl. with AVCS system.Reducing weight while maintaining durability were the primary goals in the design of this engine and was designed to be mounted as low in the car as possible. Although the FA and FB engines are used on a common platform, the FA shares very few of its parts with the FB, since it has a different block, cylinder head, connecting rods and pistons.

FA20D 

The FA20D engine built at Oizumi in Japan is equipped with injectors ( Toyota D-4S injection system ) and the Subaru CFS variable timing system. It is used in the Subaru BRZ , and is identified by a Toyota engine code under the label 4U-GSE (the same installed in the Toyota 86 and the Scion FR-S) . Subaru recommends the use of 0W-20 oil. with an 86 mm × 86 mm (3.39 in × 3.39 in) bore and stroke for 2.0 L 

From 2013 FA20D: 1998 cc DOHC, aka Toyota 4U-GSE;  Subaru BRZ/Toyota 86

• Bore × stroke: 86 × 86 mm
• Stroke: 86 mm 
• Capacity: 1998 cm ³
• Compression ratio: 12.5: 1
• Max power: 200 hp (147 kW) at 7,000  rpm
• Torque: 20.9 kg m (205 Nm; 151 lb ft) at 6,400  rpm

From 2017 to 2020 Subaru BRZ/Toyota GT86 (manual transmission)

• Power: 205 hp (153 kW; 208 PS) at 7,000 RPM
• Torque: 156 lb⋅ft (212 N⋅m; 22 kg⋅m) at 6,400 RPM

FA20F 

A Subaru version with direct injection and biturbo (twin-scroll turbocharger) was introduced in 2012. Compression ratio for the turbo engine is lower at 10.6:1 . A later revised FA20F with improvments to camshafts, rocker arms, boost pressure, intercooler, was introduced for the 2015 model year cars.

FA20F: 1998 cc DOHC, turbo, 2012+ JDM Subaru Legacy 2.0GT DIT and 2014+ Subaru Levorg; 2014+ USDM and JDM Subaru Forester XT; 2015+ USDM Subaru WRX

• Capacity: 1998 cm ³
• Bore × stroke: 86 × 86 mm
• Compression ratio: 10.6: 1
• Firing Order: 1-3-2-4

Fitted to models:

Subaru Legacy 2.0 GT DIT (2012 Japan) and Subaru Levorg (2014)

• Power: 300 hp (221 kW) at 5,600  rpm
• Torque: 40.8 kgm (400 Nm; 295 lbft) at 2,000-4,800  rpm

Subaru Forester XT (2014-2018) USA

• Power: 250 hp (186 kW) at 5,600  rpm
• Torque: 258 lbft (350 Nm; 36 kgm) from 2,000 to 4,800  rpm

 Subaru Forester badged as Forester XT: (2014-2018) (JDM)

• Power: 276 hp (206 kW; 280 PS) at 5,600 RPM
• Torque: 258 lb⋅ft (350 N⋅m; 36 kg⋅m) at 2,000-5,200 rpm

Subaru WRX (2015) USA

• Power: 268 hp (200 kW) at 5,600  rpm
• Torque: 258 lbft (350 Nm; 36 kgm) from 2,000 to 5,200  rpm

FA24F

The larger FA24F was introduced in 2018 increasing displacement to 2.4 L.The engine has now has all aluminum head and block. A turbocharger with Direct injection are now used.

2,387 cc DOHC, turbo, from 2019 on USDM Subaru Ascent, from 2020 on Subaru Legacy, and from 2020 on in the Subaru Outback.

FA24D

This has the same displacement as the FA24F turbocharged engine.with a bottom-mounted turbo with the addition of an oil cooler.

Like the FA20D, the FA24D uses the Toyota D-4S fuel injection system, which combines direct and port injection.  with an identical 94×86 mm bore and stroke, but the compression level is increased to 12.5:1. The torque curve was revised, coming at a lower engine speed and without the significant torque decrease.

• Compression Ratio: 12.5:1
• 2022+ Subaru BRZ/Toyota GR 86
• Power: 170–173 kW; 231–235 PS (228–232 hp) at 7,000 RPM
• Torque: 250 N⋅m (25.5 kg⋅m; 184.4 lb⋅ft) at 3,700 RPM