The AEM 21-863C Cold Air Intake System increases horsepower and torque by replacing the restrictive factory air filter and air intake housing on the Subaru WRX STI. The system includes an oversized AEM DRYFLOW synthetic washable air filter for outstanding airflow, filtration, and performance, plus a mandrel-bent aluminum intake tube and quality hardware. The conical filter design allows up to 100,000 miles between services under normal highway driving. A custom heat shield protects intake air from engine bay heat, and the factory fresh air duct attaches directly to the heat shield. Typical install time is under 90 minutes.
Specifications:
- Type: Cold air intake system with conical DryFlow filter
- Engine coverage: 2.5L H4
- Tubing: Mandrel-bent aluminum
- Filter: Washable, oil-free AEM Dryflow synthetic media
- Typical install time: under 90 minutes
- Part Number: 21-863C
Vehicle Applications
- 2019 Subaru WRX STI Base, Limited, S209
- 2020 Subaru WRX STI Base, Limited
- 2021 Subaru WRX STI Base, Limited
Installation Instructions
Additional Documentation
FAQ
What vehicles does the AEM 21-863C fit?
It fits the 2019-2021 Subaru WRX STI, including the Base, Limited, and 2019-only S209 trims.
How long does installation take?
AEM states this cold air intake typically installs in under 90 minutes with common hand tools.
How often does the filter need cleaning?
The oversized conical DryFlow filter can go up to 100,000 miles between cleanings under normal highway driving conditions.
