Subaru FB engine

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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. 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.

Video Subaru FB engine

Overview

The FB has an all new block and head featuring dual overhead cams with intake and exhaust variable valve timing (which Subaru designates as AVCS, standing for Active Valve Control System), and a timing chain that replaced the timing belt. Moving to chain-driven cams is said to allow the valves to be placed at a more narrow angle to each other and shrink the bore of cylinder from 99.5 mm to 94. It results in less unburned fuel during cold start, thereby reducing emissions. Subaru is able to maintain the exterior dimension substantially unchanged by using asymmetrical connecting rods like those in the EZ36 engine. The FB is only marginally heavier than an equivalent-displacement EJ. In Jan 2011, Car and Driver was told direct injection would be added soon.

Subaru claims a 28-percent reduction in friction losses, mainly due to lighter pistons and connecting rods. A compact oil pump is also credited with contributing to the reduction in friction losses. The FB has a 10% improvement in fuel economy with the power coming on sooner and the torque band being broader.

The compression ratio is slightly higher, and the stroke has increased compared to the EJ engine; previously, the chassis precluded a longer stroke. These changes improve combustion efficiency and allow higher torque at lower speeds. The FB is built at Gunma Oizumi Plant and was initially available as a 2.5 litre displacement engine, starting in Forester models, with a 2.0 litre model to follow in Imprezas. 0W-20 oil is used to help fuel economy, and approximately 1 litre more oil is used as the newly adopted timing chain requires an oil supply.

Maps Subaru FB engine

FB16

FB16

• Displacement: 1,597 cc DOHC
• Bore: 78.8 mm
• Stroke: 82 mm
• Compression: 11.0:1
• Power: 84 kW (114 PS; 113 hp) at 5,600 rpm
• Torque: 150 N?m (15 kg?m; 111 lb?ft) at 4,000 rpm
• Application: 2012+ EUDM Subaru Impreza XV 1.6i

FB16 DIT

The FB16 DIT is the first turbocharged FB-series engine, and includes direct injection with an auto stop/start system. It is the base engine in the 2014 model year Subaru Levorg. The Levorg also has an option for a 2.0 litre direct injection turbo engine, the FA20F.

• Displacement: 1,599 cc
• Bore: 78.8 mm
• Stroke: 82 mm
• Compression: 11:1
• Application: 2014+ Subaru Levorg
  • Power: 170 PS (125 kW; 168 hp) at 4,800-5,600 RPM
  • Torque: 25.5 kg?m (250 N?m; 184 lb?ft) at 1,800-4,800 RPM

src: jdmengineworld.com

FB20

The prior EJ20 used an oversquare 92 mm × 75 mm (3.6 in × 3.0 in) bore and stroke for a 1,994 cm³ (121.7 cu in) swept displacement; in comparison, the FB20 features an undersquare 84 mm × 90 mm (3.3 in × 3.5 in) bore and stroke for a slightly larger 1,995 cm³ (121.7 cu in) displacement.

FB20B

• Displacement: 1,995 cc DOHC
• Bore: 84 mm
• Stroke: 90 mm
• Compression: 10.5:1
• 2011+ JDM Subaru Forester:
  • Power: 109 kW (148 PS; 146 hp) at 6,000 rpm
  • Torque: 196 N?m (20 kg?m; 145 lb?ft) at 4,200 rpm
• 2012-2016 USDM Subaru Impreza and 2012-2017 Subaru XV:
  • Power: 148 hp (150 PS; 110 kW) at 6,200 rpm
  • Torque: 145 lb?ft (197 N?m; 20 kg?m) at 4,200 rpm

FB20D

Used in the fifth generation Impreza sedan and hatchback.

• Bore: 84 mm
• Stroke: 90 mm
• Compression: 12.5:1
• 2016+ Subaru Impreza and 2018+ Subaru XV
  • Power: 152 hp (154 PS; 113 kW), bumped to 156 PS (154 hp; 115 kW) at 6,000 RPM
  • Torque: 20.0 kg?m (196 N?m; 145 lb?ft) at 4,000 RPM

FB20X

• Displacement: 1,995 cc DOHC
• Bore: 84 mm
• Stroke: 90 mm
• Compression: 10.5:1
• Application: 2014+ Subaru XV Hybrid
  • Power: 160 hp (162 PS; 119 kW) at 6,000 rpm
  • Torque: 163 lb?ft (221 N?m; 23 kg?m) at 2,000 rpm

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FB25

Compared to the previous EJ25, which had a displacement of 2,457 cm³ (149.9 cu in) from a 99.5 mm × 79 mm (3.92 in × 3.11 in) bore and stroke, the FB25 has slightly larger displacement at 2,498 cm³ (152.4 cu in) on a 94 mm × 90 mm (3.7 in × 3.5 in) bore and stroke.

FB25B

• Displacement: 2,498 cc DOHC
• Bore: 94 mm
• Stroke: 90 mm
• Compression: 10.0:1
• Power: 170 hp (172 PS; 127 kW) at 5,800 rpm
• Torque: 174 lb?ft (236 N?m; 24 kg?m) at 4,100 rpm
• Application:
  • 2011+ North American Subaru Forester
  • 2012+ North American Subaru Legacy

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References

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External links

(Japanese: Subaru FB engine)

• Tanigawa, Kiyoshi (29 September 2010). "????????????????FB?????" [Subaru new-generation boxer "FB series" press conference]. Car Watch. Retrieved 28 February 2018. 
• "Technology: Performance -- The Subaru Boxer Engine". Subaru Global. Retrieved 28 February 2018. 
• "What's The Difference Between Subaru Engines?". Subaru of Australia. Retrieved 28 February 2018. 

Source of the article : Wikipedia