Login
Login

Subaru FB engine

{{Infobox automobile engine

| image = 5th gen Subaru Impreza FB20 engine in Automobile Council 2016.jpg

| name = Subaru FB engine

| manufacturer = Subaru

| configuration = Flat-4

| production = 2010–present

| predecessor = EJ

| successor = FA, CB

| displacement = {{ubl

| {{cvt|1599|cc|L|1|order=flip}}

| {{cvt|1995|cc|L|1|order=flip}}

| {{cvt|2498|cc|L|1|order=flip}}

}}

| bore = {{ubl

| {{cvt|78.8|mm}} {{small|(FB16)}}

| {{cvt|84|mm|2}} {{small|(FB20)}}

| {{cvt|94|mm}} {{small|(FB25)}}

}}

| stroke = {{ubl

| {{cvt|82|mm|2}} {{small|(FB16)}}

| {{cvt|90|mm|2}} {{small|(FB20 & FB25)}}

}}

| power = {{cvt|84|–|136|kW|PS hp|0}}

| torque = {{cvt|15.3|–|25.5|kgm|0|}}

| valvetrain = DOHC 4 valves x cyl. with AVCS

| turbocharger = Optional

| coolingsystem = Water-cooled

| fuelsystem = Fuel injection

| fueltype = Gasoline

| compression = 10.5:1, 11.0:1, 12.5:1

}}

The Subaru FB engine is the third generation of gasoline boxer-4 engine used in Subaru automobiles, and was announced on 23 September 2010.{{cite web |url=https://www.subaru.co.jp/en/news/archives/contents/pdf_en_60853.pdf |title=FHI Develops a New-generation Subaru Boxer Engine |date=23 September 2010 |publisher=Fuji Heavy Industries |accessdate=3 October 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.

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.

Overview

Unofficially, Subaru stated that "FB" stands for "FHI/Future and Brand New/Boxer". It was announced in September 2010 as the third generation (following the EA 1st and EJ 2nd generations) boxer engine family with 2.0 litre and 2.5 litre naturally aspirated variants.{{cite news |url=https://car.watch.impress.co.jp/docs/news/396895.html |title=スバル、新世代水平対向エンジン「FB型」説明会 |trans-title=Subaru's new-generation boxer 'FB series': briefing session |author=Tanigawa, Kiyoshi |date=29 September 2010 |work=Car Watch |accessdate=6 April 2021}} 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 {{cvt|99.5|to|94|mm}}. 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.{{cite web |url=http://www.caranddriver.com/news/subaru-fb-series-engine-subaru-flat-four-engines |title=Examining Subaru's New FB-series Flat-Four |last=Colwell |first=K.C. |date=January 2011 |work=Car and Driver |publisher=Hearst Corporation |accessdate=15 April 2011}}

Subaru claims a 28-percent reduction in friction losses, mainly due to lighter pistons and connecting rods.{{cite web |url=http://www.autocar.co.uk/CarReviews/FirstDrives/Subaru-Forester-2.0-XS/255245/ |title=Subaru Forester 2.0 XS review |last=Bremner |first=Richard |date=17 January 2011 |work=Autocar |publisher=Haymarket Media Group |accessdate=15 April 2011}} 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.{{cite magazine |url=https://www.roadandtrack.com/new-cars/car-technology/news/a17031/stroker-ace-subarus-new-fb-flat-4-engine/ |title=Stroker Ace: Subaru's New FB Flat-4 Engine |author=Kott, Douglas |date=13 April 2011 |magazine=Road & Track |accessdate=28 February 2018}}

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.{{cite news |url=https://car.watch.impress.co.jp/docs/news/401853.html |title=スバルの新世代水平対向エンジン「FB型」の疑問点を確認 |trans-title=Subaru's new-generation boxer "FB series": questions answered |author=Tanigawa, Kiyoshi |date=22 October 2010 |work=Car Watch |accessdate=28 February 2018}}

FB16

All FB16 variants:

  • Displacement: {{cvt|1600|cc|L|1}} DOHC
  • Bore x stroke: {{cvt|78.8x82|mm}}

=FB16=

File:Subaru FB16 NA.JPG

  • Compression: 11.0:1
  • 2012+ EUDM Subaru Impreza XV 1.6i
  • Power: {{cvt|84|kW|PS hp|0}} at 5,600 rpm
  • Torque: {{cvt|15.3|kg.m|Nm lbft|0}} at 4,000 rpm
  • 2017+ EUDM Subaru Impreza and 2018+ Subaru XV
  • Power: {{cvt|84|kW|PS hp|0}} at 6,200 rpm
  • Torque: {{cvt|15.3|kg.m|Nm lbft|0}} at 3,600 rpm
  • 2017+ JDM Subaru Impreza and 2018+ Subaru XV
  • Power: {{cvt|115|PS|kW hp|0}} at 6,200 rpm
  • Torque: {{cvt|15.1|kg.m|Nm lbft|0}} at 3,600 rpm

=FB16 DIT=

File:Subaru 1.6 DIT engine.jpg

The FB16 direct injection turbocharged (DIT) engine is the first FB-series engine with a turbocharger, and includes direct injection with an auto stop/start system. It is the base engine in the first-generation (2014–20 model years) Subaru Levorg. The Levorg also has an option for a 2.0 litre direct injection turbo engine, the FA20F.{{cite press release |url=https://www.media.subaru-global.com/en/news/1802 |title=World Premiere of Subaru "LEVORG" at 43rd Tokyo Motor Show 2013 |date=20 November 2013 |publisher=Subaru Global |accessdate=28 February 2018}}{{cite web |url=http://www.subaru-global.com/ebrochure/Levorg/2016my/EC/assets/media/pdf/16S_LV_EC_spec.pdf |title=Levorg Brochure, Model Year 2016 |publisher=Subaru Global |accessdate=28 February 2018}} The design target for the FB16 DIT engine was to equal or exceed the performance of the FB25 naturally-aspirated engine fitted to the Legacy, using regular gasoline, according to the designer, Rei Sasaki. Although it shares its displacement with the naturally aspirated FB16, the only part the two engines share is the crankshaft. As fitted to the Levorg, the FB16 DIT was able to achieve fuel economy of {{cvt|16.0|km/L|mpgUS}} on the JC08 cycle.{{cite web |url=http://www.subaru.jp/about/technology/story/dit/dit01.html |title=1.6l DIT Engine |date=October 2014 |publisher=Subaru Corporation |archive-url=https://web.archive.org/web/20141015181838/http://www.subaru.jp/about/technology/story/dit/dit01.html |archive-date=October 15, 2014 |url-status=dead}}

  • Compression: 11.0:1
  • Application: 2014–20 Subaru Levorg
  • Power: {{cvt|125|kW|PS hp|0}} at 4,800–5,600 RPM
  • Torque: {{cvt|25.5|kgm|0}} at 1,800–4,800 RPM

FB20

The prior EJ20 used an oversquare {{cvt|92|×|75|mm|2}} bore and stroke for a {{cvt|1994|cc|L|1}} swept displacement; in comparison, the FB20 features an undersquare bore and stroke for a slightly larger displacement.

All FB20 variants:

  • Displacement: {{cvt|1995|cc|L|1}} DOHC
  • Bore x stroke: {{cvt|84|×|90|mm|2}}

=FB20B=

File:2015 Subaru XV 2.0i FB20 engine.jpg

  • Compression: 10.5:1
  • 2011+ JDM Subaru Forester:{{cite web |url=http://www.subaru.com.au/news/subaru-boxer-punches-harder |title=Subaru Boxer Punches Harder |date=23 September 2010 |publisher=Subaru Australia |accessdate=3 October 2010}}
  • Power: {{cvt|109|kW|PS hp|0}} at 6,000 rpm
  • Torque: {{cvt|20|kgm|0}} at 4,200 rpm
  • 2012–2016 USDM Subaru Impreza and 2012–2017 Subaru XV:
  • Power: {{cvt|110|kW|PS hp|0}} at 6,200 rpm
  • Torque: {{cvt|20|kgm|0}} at 4,200 rpm

=FB20X=

File:The engine room of Subaru IMPREZA SPORT HYBRID 2.0i-S EyeSight (DAA-GPE).JPG

The existing FB20B was modified by reducing internal friction for the hybrid drivetrain, which incorporates an electric motor in the Lineartronic CVT. The high-voltage traction battery is installed below the cargo area for better weight balance.{{cite press release |url=https://www.subaru.co.jp/en/news/archives/press/2013/13_03_29e_1_87456.html |title=FHI Introduces the "Subaru XV Crosstrek Hybrid" at the 2013 New York International Auto Show — First-Ever Production Hybrid model — |date=March 29, 2013 |publisher=Fuji Heavy Industries Ltd. |accessdate=24 April 2019}} Combined system power is stated to be {{cvt|160|hp|kW|0}}.{{cite web |url=http://www.subaru.com/content/downloads/pdf/brochures/2014_XV_Crosstrek.pdf |title=2014 XV Crosstrek, XV Ctrosstrek Hybrid brochure |publisher=Subaru |archive-url=https://web.archive.org/web/20141212053133/http://www.subaru.com/content/downloads/pdf/brochures/2014_XV_Crosstrek.pdf |archive-date=12 December 2014 |url-status=dead}} Output of the gasoline engine is comparable to that of the non-hybrid FB20B.{{cite web |url=http://www.subaru.jp/xv/xv/spec/pdf/xv_specifications.pdf |title=Subaru XV Specifications |publisher=Subaru |archive-url=https://web.archive.org/web/20130512152909/http://www.subaru.jp:80/xv/xv/spec/pdf/xv_specifications.pdf |archive-date=12 May 2013 |url-status=dead}}

  • Compression: 10.8:1
  • Application: 2014–16 Subaru XV Hybrid{{cite news |url=https://www2.greencarreports.com/news/1106428_subaru-crosstrek-hybrid-discontinued-for-2017-model-year |title=Subaru Crosstrek Hybrid discontinued for 2017 model year |author=Edelstein, Stephen |date=October 3, 2016 |work=Green Car Reports |accessdate=24 April 2019}}
  • Combined system output:
  • Power: {{cvt|160|hp|PS kW|0}} at 6,000 rpm
  • Torque: {{cvt|163|lbft|Nm kgm|0}} at 2,000 rpm
  • Gasoline engine output:{{cite magazine |url=https://www.caranddriver.com/reviews/a15111265/2014-subaru-xv-crosstrek-hybrid-test-review/ |title=2014 Subaru XV Crosstrek Hybrid |author=Wilson, Kevin A. |date=May 29, 2014 |magazine=Car and Driver |accessdate=24 April 2019}}
  • Power: {{cvt|148|hp|PS kW|0}}
  • Torque: {{cvt|145|lbft|Nm kgm|0}}
  • Electric motor output:
  • Power: {{cvt|13.4|hp|PS kW|0}}
  • Torque: {{cvt|48.0|lbft|Nm kgm|0}}

=FB20D=

Used in the fifth generation Impreza sedan and hatchback; compared to the FB20B, the FB20D adds direct injection, providing a slight increase in power and efficiency.{{cite press release |url=http://www.media.subaru.com/newsrelease.do?id=929&mid=138&allImage=1&teaser=subaru-introduces-all-new-u.s-built-2017-impreza |title=Subaru introduces all-new, U.S.-built 2017 Impreza; new Global Platform delivers major gains in handlign performance, crash safety and ride comfort |publisher=Subaru of America |accessdate=24 April 2019}}{{cite news |url=https://www.torquenews.com/1084/here-s-how-subaru-s-new-20l-engine-improves-2017-impreza-it-gets-2-important-upgrades |title=Here's How Subaru's New 2.0L Engine Improves the 2017 Impreza; It Gets 2 Important Upgrades |author=Flierl, Denis |date=November 25, 2016 |work=Torque News |accessdate=24 April 2019}}

  • Compression: 12.5:1
  • 2017+ Subaru Impreza{{cite press release |url=https://www.media.subaru-global.com/en/news/2205 |title=World Premiere of All-New Subaru Impreza at New York International Auto Show |date=24 March 2016 |publisher=Subaru Corporation |accessdate=15 March 2018}} (All trims) and 2018+ Subaru XV/Crosstrek (Base & Premium trims only){{cite press release |url=https://www.media.subaru-global.com/en/news/2401 |title=World Premiere of All-New Subaru XV at 2017 Geneva International Motor Show |date=7 March 2017 |publisher=Subaru Corporation |accessdate=15 March 2018}}
  • Power (JDM, USDM) : {{cvt|113|kW|PS hp|0}} at 6,000 RPM
  • Power (EUDM, AUDM, THDM): {{cvt|115|kW|PS hp|0}} at 6,000 RPM
  • Torque: {{cvt|20|kgm|0}} at 4,000 RPM

File:SUBARU FB20D ENGINE.jpg

=FB20V=

The 2019 Crosstrek is available with a plug-in hybrid system sourced from Toyota.{{cite news |url=https://www.cnet.com/roadshow/reviews/2019-subaru-crosstrek-hybrid-preview/ |title=2019 Subaru Crosstrek Hybrid first drive review: Worth the extra charge |author=Carrillo III, Manual |date=November 19, 2018 |work=C{{!}}Net |accessdate=24 April 2019}} The new hybrid drivetrain uses two motor-generator units; the traction motor (MG2) and battery are significantly larger compared to the previous XV Crosstrek Hybrid, and the vehicle is capable of moving under electric power alone for a limited distance. MG2 is used under parallel hybrid operation as well. MG1 is used as the starter motor and charges the battery for series hybrid operation. The direct-injection FB20V in the revised hybrid is detuned compared to the conventional FB20D.{{cite web |url=http://subarumedia.iconicweb.com/mediasite/attachments/2019_Crosstrek_Hybrid_specs-FINAL.PDF |title=2019 Subaru Crosstrek® Hybrid Specifications |publisher=Subaru of America |accessdate=24 April 2019}}

  • Application: 2019+ Subaru Crosstrek Hybrid (PHEV)
  • Combined system output:
  • Power: {{cvt|148|hp|PS kW|0}}

  • Gasoline engine output:{{cite press release |url=https://www.subaru.co.jp/press/news-en/2018_11_20_6537/ |title=Subaru Introduces its First Plug-In Hybrid Vehicle, the Crosstrek Hybrid, in the U.S. |date=November 20, 2018 |publisher=Subaru Corporation |accessdate=24 April 2019}}
  • Power: {{cvt|137|hp|PS kW|0}} at 5,600 RPM
  • Torque: {{cvt|134|lbft|Nm kgm|0}} at 4,400 RPM
  • Electric traction motor (MG2) output:{{cite magazine |url=https://www.motortrend.com/cars/subaru/crosstrek/2019/2019-subaru-crosstrek-hybrid-first-test-review/ |title=2019 Subaru Crosstrek Hybrid first test: Quietly off-roading into the future |author=Cantu, Michael |date=December 6, 2018 |magazine=Motor Trend |accessdate=24 April 2019}}
  • Power: {{cvt|118|hp|PS kW|0}}
  • Torque: {{cvt|149|lbft|Nm kgm|0}}

=FB20D e-Boxer=

The direct-injection FB20D was also used in a mild parallel hybrid configuration similar to the FB20X. The mild hybrid drivetrain was fitted to selected trims for models sold in Japan (Forester, July 2018 and XV, October 2018),{{cite web |url=https://www.subaru.co.jp/en/csr/environment/030_friendlyautomobiles.html |title=Our Approach to Environmentally Friendly Automobiles |publisher=Subaru Corporation |accessdate=24 April 2019}} Europe (same models, starting in 2019),{{cite press release|url=https://www.subaru.co.jp/press/news-en/2019_03_05_6990/|title=Subaru unveiled European spec 'e-Boxer' equipped models at Geneva International Motor Show|publisher=Subaru Corporation|date=March 5, 2019|accessdate=24 April 2019}} and Australia (same models, starting in 2020).{{Cite web|title=New Subaru Forester and XV 2020 Hybrid e-Boxers sold out: Here's when you'll be able to get your hands on one|url=https://www.carsguide.com.au/car-news/new-subaru-forester-and-xv-2020-hybrid-e-boxers-sold-out-78200|access-date=2021-05-12|website=CarsGuide|language=en}}

  • Application: 2019+ JDM and EUDM Subaru XV and Forester, selected models
  • Combined system output:
  • Power: {{cvt|107|kW|PS hp|0}} at 6,000 rpm
  • Torque: {{cvt|188|Nm|kgm lbft|0}} at 4,000 rpm
  • Gasoline engine output:{{cite news |url=https://www.torquenews.com/1084/subaru-reveals-japan-spec-forester-e-boxer-hybrid-details |title=Subaru Reveals Japan-Spec Forester e-Boxer Hybrid Details |author=Flierl, Denis |date=May 18, 2018 |work=Torque News |accessdate=24 April 2019}}
  • Power: {{cvt|145|PS|kW hp|0}}
  • Torque: {{cvt|188|Nm|kgm lbft|0}}
  • Electric motor output:{{cite web |url=https://www.subaru.jp/xv/xv/grade/grade.html#grade5 |title=Subaru XV Advance |publisher=Subaru of Japan |accessdate=24 April 2019}}
  • Power: {{cvt|10|kW|PS hp|0}}
  • Torque: {{cvt|65|Nm|kgm lbft|0}}

FB25

Compared to the previous EJ25, which had a displacement of {{cvt|2457|cc|L|1}} from an oversquare {{cvt|99.5|×|79|mm}} bore and stroke, the FB25 has slightly larger displacement on a less oversquare bore and stroke.

All FB25 variants:

  • Displacement: {{cvt|2498|cc|L|1}} DOHC
  • Bore x stroke: {{cvt|94|×|90|mm|2}}

=FB25B=

File:Ray Baldwin Subaru Stamford NY Auto Show 021.JPG

  • Compression: 10.0:12011 Subaru Forester & Impreza Owner's Manual
  • Power: {{cvt|170|hp|PS kW|0}} at 5,800 rpm{{cite web |url=http://www.carsguide.com.au/car-news/subaru-reveals-new-boxer-engine-17805 |title=Subaru reveals new boxer engine |last=Hinchliffe |first=Mark |date=28 September 2010 |publisher=CarsGuide.com.au |accessdate=3 October 2010}}
  • Torque: {{cvt|174|lbft|Nm kgm|0}} at 4,100 rpm
  • Application:
  • 2011–18 North American Subaru Forester
  • 2013–19 North American Subaru Legacy
  • 2013–19 North American Subaru Outback

=FB25D=

File:2023 Subaru Outback Limited 2.5 liter 4 cyl engine bay.jpg

The 2019 model year Subaru Forester was introduced at the 2018 New York International Auto Show with a revised version of the FB25 engine featuring direct injection, resulting in a slight boost in power and fuel economy.{{cite press release |url=https://www.subaru.co.jp/press/news-en/2018_03_29_5579/ |title=World Premier of All-New 2019 Forester at New York International Auto Show |date=March 29, 2018 |publisher=Subaru Corporation |accessdate=3 April 2019}} The seventh-generation 2020 model year Legacy and Outback also adopted the revised direct-injection FB25D as its base engine.{{cite press release |url=https://www.subaru.co.jp/press/news-en/2019_02_08_6884/ |title=World Premier of All-New 2020 Subaru Legacy Sedan |date=February 8, 2019 |publisher=Subaru Corporation |accessdate=3 April 2019}}{{cite press release |url=https://www.subaru.co.jp/press/news-en/2019_04_18_7147/ |title=World Premier of All-New 2020 Subaru Outback |date=April 17, 2019 |publisher=Subaru Corporation |accessdate=17 April 2019}}

  • Compression: 12.0:1
  • 2019–2024 Subaru Forester, 2020–2025 Subaru Legacy (non-XT), 2020–2025 Subaru Outback (non-XT, non-Wilderness), 2021+ Subaru Crosstrek (USDM Premium (2025+), Sport, Limited, and Wilderness trims; Canadian Outdoor, Onyx, and Wilderness trims)
  • Power: {{cvt|182|hp|PS kW|0}} at 5,800 rpm
  • Torque: {{cvt|176|lbft|Nm kgm|0}} at 4,400 rpm
  • 2025+ Subaru Forester, 2026+ Subaru Outback (non-XT, non-Wilderness)
  • Power: {{cvt|180|hp|PS kW}} at 5,800 rpm{{Cite web |title=2025 Subaru Forester Specs & Features |url=https://www.edmunds.com/subaru/forester/2025/features-specs/ |access-date=2024-06-15 |website=Edmunds |language=en-us}}
  • Torque: {{cvt|178|lbft|Nm kgm}} at 3,700 rpm
  • 2024+ Subaru Impreza (RS trim)
  • Power: {{cvt|182|hp|PS kW}} at 5,800 rpm{{Cite web |title=2025 Subaru Forester Specs & Features |url=https://www.subaru.com|website=Edmunds |language=en-us}}
  • Torque: {{cvt|178|lbft|Nm kgm}} at 3,700 rpm

References

{{Reflist}}

External links

{{Commons category|Subaru FB engines}}

({{langx|ja|Subaru FB engine}})

  • {{cite news |url=https://car.watch.impress.co.jp/docs/news/396895.html |title=スバル、新世代水平対向エンジン「FB型」説明会 |trans-title=Subaru new-generation boxer "FB series" press conference |author=Tanigawa, Kiyoshi |date=29 September 2010 |work=Car Watch |accessdate=28 February 2018}}
  • {{cite web |url=https://www.subaru-global.com/technology/performance/drivetrain_boxerengine.html |title=Technology: Performance — The Subaru Boxer Engine |publisher=Subaru Global |accessdate=28 February 2018}}
  • {{cite web |url=https://www.subaru.com.au/subaru-dna/subaru-engine-range |title=What's The Difference Between Subaru Engines? |publisher=Subaru of Australia |accessdate=28 February 2018}}

{{subaru}}

{{DEFAULTSORT:Subaru Fb Engine}}

Category:Subaru engines

Category:Boxer engines

Category:Gasoline engines by model

Category:Four-cylinder engines