Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Subaru WRX BaseFACTORY OEM SERVICE PROCEDURE
WRX STI: Engine
| Model | 2.5 L DOHC high power turbo |
| Engine type | Horizontally opposed, liquid cooled, 4-cylinder, 4-stroke gasoline engine |
| Valve arrangement | DOHC |
| Bore x stroke mm (in) | 99.5 x 79.0 (3.92 x 3.11) |
| Displacement cm3 (cu in) | 2, 457 (150) |
| Compression ratio | 8.2 |
| Ignition order | 1 - 3 - 2 - 4 |
| Idle speed at parking or neutral position r/min | 700±100 |
| Maximum output kW (HP)/(r/min) | 231 (310)/6, 000 |
| Maximum torque N.m (kgf-m, ftlb)/(r/min) | 393 (40.2, 290)/4, 000 - 5, 200 |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.