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Subaru EJ specs: 2.0L (121.9 ci) 4-cylinder, 92 x 75 mm (3.6220 x 2.9528 in) bore and stroke, 8:1 compression. Rated 227-280 hp. Rod ratio and piston speed.
The Subaru EJ is oversquare — the 3.622" bore exceeds the 2.9528" stroke by 22.7% — a layout that favors airflow and RPM over leverage at the crank. The 2.9528" stroke does not reach 4,000 ft/min of mean piston speed until about 8,150 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 30.5 ci (499 cc).
8:1 on aluminum heads is low by modern standards and generally happy on regular pump fuel.
It is one of 37 engines in the EJ family, sitting between the 91.1 ci and 152 ci members. 2 factory variants share these dimensions, rated from 227 to 280 hp. Factory fitments include the Subaru Impreza WRX STi (GC8), Subaru Impreza WRX (GD), Subaru Forester XT (SG).
| Displacement | 121.9 ci / 2 L |
|---|---|
| Bore | 3.622" |
| Stroke | 2.9528" |
| Cylinders | 4 |
| Compression ratio | 8:1 |
| Bore/stroke ratio | 1.227 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 227–280 hp |
| Bore/stroke character | 1.227 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,953 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.5 ci |
| Static compression | 8:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| — | 227 hp | EJ205/EJ207 (AVCS) |
| — | 280 hp | EJ20K/EJ207 (early) |