The Subaru FA24 is a 2.4-liter boxer four-cylinder engine family with two main road-car variants. The turbocharged FA24F, also called FA24DIT, powers vehicles including the Subaru Ascent, Outback XT, Legacy XT, and 2022+ WRX. The naturally aspirated FA24D powers the second-generation Subaru BRZ and Toyota GR86.
Quick answer: both engines displace 2,387 cc and share a 94 mm bore and 86 mm stroke, but they are not interchangeable versions of the same complete engine. The FA24F uses direct injection and a twin-scroll turbocharger. The FA24D uses Toyota’s D-4S system with direct and port injection, has a higher compression ratio, and does not have a factory turbocharger. Vehicle-specific output, intake and exhaust hardware, electronics, oiling, transmission interfaces, and calibrations also differ.
This guide covers the FA24F and FA24D road-car variants. For detailed 2022+ WRX diagnosis, continue to the FA24DIT common problems and reliability guide. The Subaru WRX engine guide compares the FA24DIT with the EJ205, EJ255, EJ257, and FA20DIT.
On this page
- FA24 engine specifications
- FA24F, FA24DIT, and FA24D names explained
- Which vehicles use the FA24F engine?
- Which vehicles use the FA24D engine?
- FA24F vs. FA24D
- How the FA24 differs from the FA20
- Is the FA24 engine reliable?
- Timing chain, fuel injection, and valve deposits
- FA24 tuning and power
- Buying a used FA24 engine
- FA24 engine FAQ
- Subaru FA24 Engine FAQ
- Sources
FA24 engine specifications
| Specification | FA24F / FA24DIT | FA24D |
|---|---|---|
| Configuration | Horizontally opposed four-cylinder | Horizontally opposed four-cylinder |
| Displacement | 2,387 cc | 2,387 cc |
| Bore x stroke | 94.0 x 86.0 mm | 94.0 x 86.0 mm |
| Cylinder block and heads | Aluminum | Aluminum |
| Valvetrain | DOHC, four valves per cylinder, Dual AVCS | DOHC, four valves per cylinder, Dual AVCS |
| Cam drive | Timing chain | Timing chain |
| Fuel system | Direct injection | Toyota D-4S direct and port injection |
| Induction | Turbocharged and intercooled | Naturally aspirated |
| Compression ratio | 10.6:1 | 12.5:1 |
| Main US applications | Ascent, Legacy XT/Sport, Outback XT/Wilderness, WRX | Subaru BRZ, Toyota GR86 |
Subaru’s factory documents confirm the shared dimensions while showing how differently the engines are configured. The 2019 Ascent specifications list a 2,387 cc turbocharged engine with direct injection, a 10.6:1 compression ratio, chain-driven camshafts, and Dual Active Valve Control System. The 2022 BRZ specifications list the same displacement and bore/stroke dimensions, but with direct and port injection, natural aspiration, and a 12.5:1 compression ratio.
Use the full engine variant, vehicle, model year, market, and part number when identifying an FA24 or ordering major components.
FA24F, FA24DIT, and FA24D names explained
FA24F is Subaru’s designation for the turbocharged version. FA24DIT is a widely used descriptive name: “DIT” refers to direct-injection turbo. Parts catalogs, tuners, dismantlers, and owners use FA24F and FA24DIT for the same broad turbo engine branch.
FA24D identifies the naturally aspirated engine used in the second-generation BRZ and GR86.
Sellers often shorten both variants to “FA24.” A useful listing should identify the donor vehicle, model year, market, and complete or partial assembly being sold.
Which vehicles use the FA24F engine?
The FA24F first reached the US market in the 2019 Subaru Ascent. Subaru later installed the turbocharged 2.4-liter engine in the Legacy, Outback, and WRX. Overseas applications include versions of the Levorg and WRX S4.
| US-market application | Model years | Factory output |
|---|---|---|
| Subaru Ascent | 2019+ | 260 hp at 5,600 rpm; 277 lb-ft at 2,000-4,800 rpm |
| Subaru Legacy XT | 2020-2025 | 260 hp at 5,600 rpm; 277 lb-ft at 2,000-4,800 rpm |
| Subaru Legacy Sport with 2.4-liter turbo | 2023-2025 | 260 hp at 5,600 rpm; 277 lb-ft at 2,000-4,800 rpm |
| Subaru Outback XT | 2020+ | 260 hp at 5,600 rpm; 277 lb-ft at 2,000-4,800 rpm |
| Subaru Outback Wilderness | 2022+ | 260 hp at 5,600 rpm; 277 lb-ft at 2,000-4,800 rpm |
| Subaru WRX | 2022+ | 271 hp at 5,600 rpm; 258 lb-ft at 2,000-5,200 rpm |
The output difference is application-specific. Subaru’s 2020 Legacy technical specifications document 260 horsepower, 277 lb-ft, and an 87-AKI fuel specification for that vehicle. The 2022 WRX specifications list 271 horsepower, 258 lb-ft, and 91 AKI recommended for maximum performance.
Which vehicles use the FA24D engine?
The FA24D arrived with the second-generation Subaru BRZ and Toyota GR86. In US-market 2022 BRZ specifications, Subaru rates it at 228 horsepower at 7,000 rpm and 184 lb-ft at 3,700 rpm.
Its character is different from the FA24F:
- It is naturally aspirated and designed to make power at higher engine speed.
- D-4S combines port and direct fuel injection.
- Its 12.5:1 compression ratio is higher than the FA24F’s 10.6:1 ratio.
- It is installed longitudinally in a rear-wheel-drive sports-car platform.
- Its intake, exhaust, oiling layout, accessories, wiring, ECU, and transmission interfaces fit the BRZ/GR86 package.
The FA24D’s combined injection system is an important practical difference. Port injectors can deliver fuel upstream of the intake valves during applicable operating conditions, while the FA24F relies on direct injection into the combustion chamber.
FA24F vs. FA24D
| Difference | FA24F / FA24DIT | FA24D |
|---|---|---|
| Intended vehicles | Turbo Subaru crossovers, sedans, wagons, and WRX | BRZ and GR86 sports cars |
| Airflow | Twin-scroll turbocharger and intercooler | Naturally aspirated intake |
| Fuel delivery | Direct injection only | Direct and port injection |
| Compression ratio | 10.6:1 | 12.5:1 |
| US factory output | 260-271 hp depending on application | 228 hp in the US-market BRZ |
| US factory torque | 258-277 lb-ft depending on application | 184 lb-ft in the US-market BRZ |
How the FA24 differs from the FA20
The FA24 increased bore from the FA20 family’s 86 mm to 94 mm while retaining an 86 mm stroke. Displacement rose from approximately 2.0 liters to 2.4 liters.
The relevant comparison depends on the car:
- FA20DIT vs. FA24F: the 2015-2021 WRX uses the 2.0-liter turbo FA20DIT, while the 2022+ WRX uses the 2.4-liter turbo FA24F. Both use direct injection and turbocharging, but their engine hardware, electronics, airflow paths, and calibrations are platform-specific.
- FA20D vs. FA24D: the first-generation BRZ/FR-S/86 uses the 2.0-liter FA20D, while the second generation uses the 2.4-liter FA24D. Both use D-4S combined injection and natural aspiration.
For a broader comparison of Subaru’s 2.0-liter variants, see the Subaru FA20 engine guide. The VA vs. VB WRX guide compares the complete cars rather than reducing the generation change to displacement.
Is the FA24 engine reliable?
The answer depends on the variant, vehicle, use, and evidence available. The earliest US FA24F applications are 2019 models, and FA24D cars began with the 2022 model year. That provides useful ownership history, but less high-mileage evidence than older EJ and FA20 engines.
For a used FA24-powered car, the most useful engine-health evidence includes:
- Recorded oil consumption or a stable oil level between services.
- Cold-start behavior, current and stored diagnostic codes, and the cause of any previous misfire.
- Repair records for overheating, oil-pressure warnings, engine removal, oil-pan work, or internal damage.
- A complete hardware and calibration history for a modified FA24F.
- Oil-pressure data and oiling changes on a BRZ or GR86 used on track.
FA24F reliability areas
On a 2022+ WRX, the main areas covered in our detailed guide are:
- Oil level, consumption, leaks, and oil-pressure symptoms.
- Intake-valve deposits after other causes of rough running have been tested.
- Heat soak versus actual engine overheating.
- Upstream intake or vacuum leaks versus pressurized charge-air leaks.
- Spark plugs, coils, injectors, and cylinder-specific misfires.
- Hardware, fuel, and ECU calibration mismatches.
See FA24DIT common problems for the diagnostic sequence. The separate FA24 RTV oil-pickup guide examines reported sealant debris, oil-pressure evidence, and when oil-pan inspection is justified.
FA24D reliability areas
BRZ and GR86 use brings a different set of questions:
- Oil level and oil-pressure behavior during sustained cornering or track use.
- Oil-pan and pickup inspection when symptoms, pressure data, or prior work justify it.
- Cooling and oil-temperature behavior during repeated high-load driving.
- Ignition, injector, and air-fuel diagnosis for misfires or rough running.
- Calibration and fuel compatibility on modified cars.
- Records for track use, over-revs, engine work, and aftermarket oiling parts.
For track use, evaluate measured oil pressure, oil and coolant temperatures, tires, and sustained cornering loads for the specific car and venue. The BRZ turbo-kit guide covers the additional supporting systems involved when forced induction is added.
Timing chain, fuel injection, and valve deposits
Both FA24 variants use chain-driven camshafts. Chain noise or cam/crank correlation codes require diagnosis using the service information for the exact application.
The direct-injected FA24F does not spray fuel across the backs of the intake valves, so oil vapor and residue can accumulate there. The FA24D’s D-4S system also uses port injectors. Rough idle, cold-start misfire, and hesitation can come from ignition, fueling, air leaks, compression, or calibration, so those systems should be tested before intake-valve cleaning is selected.
FA24 tuning and power
FA24F and FA24D modification paths are fundamentally different. A WRX tune manages turbocharger boost, direct injection, ignition, torque targets, and drivetrain behavior. A naturally aspirated BRZ or GR86 calibration works with a different fuel system, airflow model, exhaust layout, compression ratio, and drivetrain.
On an FA24F, the calibration must match the fuel, airflow hardware, boost-control system, turbocharger, and transmission. An FA24D forced-induction build adds fuel-system, cooling, clutch or transmission, and calibration requirements that do not exist in the stock naturally aspirated configuration.
Compare dyno results from similar configurations tested on the same equipment. For WRX calibration planning, see the WRX tuning guide and e-tune vs. dyno-tune comparison.
Buying a used FA24 engine
Listings for an “FA24 engine” may describe a short block, long block, complete engine, or partial assembly. Confirm what is included before comparing prices.
For a replacement engine, document:
- FA24F or FA24D designation.
- Donor model, year, market, VIN, and mileage.
- Engine assembly and component part numbers.
- Included cylinder heads, fuel system, turbo, intake, exhaust, sensors, wiring, and accessories.
- Transmission interface and application-specific mounting parts.
- Compression, leakdown, oil-pressure, and running-condition evidence when available.
- Warranty terms, required installation procedures, and excluded components.
For an FA24F replacement, buy an engine documented for the recipient model, model year, market, and transmission unless the installer has already identified every different part number and the additional parts required. For an FA24D, verify BRZ or GR86 application and model year.
FA24 engine FAQ
Subaru FA24 Engine FAQ
Is the FA24F the same as the FA24DIT?
FA24F is Subaru’s turbocharged 2.4-liter FA engine designation, while FA24DIT is the common descriptive name for the direct-injection turbo version. Confirm the donor vehicle and part numbers because hardware and output differ among FA24F applications.
Is the FA24D the same engine as the FA24F?
No. They share 2,387 cc displacement and 94 x 86 mm bore and stroke dimensions, but the FA24D is naturally aspirated, uses combined port and direct injection, and has a 12.5:1 compression ratio. The FA24F is turbocharged, direct-injected, and has a 10.6:1 compression ratio.
What cars have the FA24F engine?
US applications include the 2019+ Subaru Ascent, turbocharged 2020+ Legacy and Outback trims, and the 2022+ WRX. Model years and trim availability should be checked for the exact market.
What cars have the FA24D engine?
The FA24D is used in the second-generation Subaru BRZ and Toyota GR86, beginning with the 2022 model year in the United States.
Does the FA24 use a timing belt?
No. Production FA24F and FA24D engines use chain-driven camshafts.
Sources
- 2019 Subaru Ascent specifications - FA24F dimensions, compression ratio, induction, output, and valvetrain.
- 2020 Subaru Legacy world premiere and specifications - turbo FA24 specifications and fuel requirement for the US-market Legacy.
- 2022 Subaru WRX specifications - WRX output, induction, fuel recommendation, and valvetrain.
- 2022 Subaru BRZ specifications - FA24D dimensions, compression ratio, combined injection, output, and valvetrain.
- 2026 Subaru Ascent specifications - current FA24F Ascent output and application.
- 2026 Subaru Outback specifications - current turbo Outback output and trim applications.
- 2026 Subaru WRX engine information - current WRX output, direct injection, and twin-scroll turbocharger.
- 2019 Subaru Ascent FA24F engine photograph - photo by Mr.choppers, adapted under CC BY-SA 3.0.
