See other engines in this family
Subaru FA24 specs: 2.4L (146 ci) 4-cylinder, 94 x 86 mm (3.7008 x 3.3858 in) bore and stroke, 12.5:1 compression. Rated 228 hp, 2022–2026.
The Subaru FA24 is oversquare — the 3.7008" bore exceeds the 3.3858" stroke by 9.3% — a layout that favors airflow and RPM over leverage at the crank. The 3.3858" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 36.5 ci (598 cc).
12.5:1 on aluminum heads is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 14 engines in the FA family, sitting between the 121.9 ci and 146.5 ci members. 5 factory variants share these dimensions, rated at 228 hp across 2022–2026.
| Displacement | 146 ci / 2.4 L |
|---|---|
| Bore | 3.7008" |
| Stroke | 3.3858" |
| Cylinders | 4 |
| Compression ratio | 12.5:1 |
| Bore/stroke ratio | 1.093 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 228 hp |
| Years | 2022–2026 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2022 | FA24D net | 228 @ 7000 | 184 lb-ft @ 3700 | 12.5:1 |
| 2023 | FA24D net | 228 @ 7000 | 184 lb-ft @ 3700 | 12.5:1 |
| 2024 | FA24D net | 228 @ 7000 | 184 lb-ft @ 3700 | 12.5:1 |
| 2025 | FA24D net | 228 @ 7000 | 184 lb-ft @ 3700 | 12.5:1 |
| 2026 | FA24D net | 228 @ 7000 | 184 lb-ft @ 3700 | 12.5:1 |
Factory specification sheet.
| Bore/stroke character | 1.093 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,386 ft/min — conservative for a street engine |
| Displacement per cylinder | 36.5 ci |
| Static compression | 12.5:1 — high enough that pump premium or better is normally required |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 2022 | 228 hp | FA24 |
| 2023 | 228 hp | FA24 |
| 2024 | 228 hp | FA24 |
| 2025 | 228 hp | FA24 |
| 2026 | 228 hp | FA24 |
1 factory vehicle, 2022–2026. Each year opens that model's engine table.