AEM Induction 21-863C Cold Air Intake System for 2019-2021 Subaru WRX STI 2.5L H4

AEM cold air intake systems are designed to increase horsepower and torque. The system includes an oversized AEM DRYFLOW synthetic washable air filter, engineered to provide outstanding airflow, filtration, and performance, and also features a mandrel-bent aluminum intake tube and high quality hardware. The oversized, conical filter design allows you to go up to 100,000 miles between filter services under normal highway driving conditions. A custom heat shield helps protect intake air from the high temperature of your engine bay, and the factory fresh air duct attaches to the heat shield. The entire system can typically be installed in less than 90 minutes. AEM's mandrel-bent aluminum cold air intake systems are guaranteed to provide an increase in horsepower and torque, and are protected by the AEM Lifetime Limited Warranty. Associated products: AEM-21-2157DK DryFlow Air Filter, AEM-1-1000 Air Filter Cleaner

• Utilizes washable, reusable, oil-free synthetic filter media that preserves airflow efficiency, traps harmful contaminants, and provides long-term value over disposable filters.

Brief Description: The AEM Induction 21-863C Cold Air Intake System is engineered for the 2019-2021 Subaru WRX STI with the 2.5L H4 engine. This performance intake is designed to improve airflow to the engine, supporting increased horsepower, torque, throttle response, and overall intake efficiency. The system combines a mandrel-bent aluminum intake tube, an oversized AEM DRYFLOW synthetic air filter, a custom heat shield, and high-quality installation hardware.

The washable, reusable, oil-free synthetic filter media provides effective contaminant filtration without requiring filter oil. Its oversized conical design supports extended service intervals of up to 100,000 miles under normal highway driving conditions. The custom heat shield helps reduce exposure to high engine-bay temperatures, while the factory fresh-air duct connects to the shield to help maintain a consistent supply of cooler intake air. Installation can typically be completed in less than 90 minutes using common hand tools.

Fitment: This intake system fits 2019, 2020, and 2021 Subaru WRX STI models equipped with the 2.5L H4 engine. The AEM Induction 21-863C is not CARB approved and may not be legal for use on pollution-controlled vehicles in certain states or regions. Review local emissions regulations before installation. The system is backed by AEM's Lifetime Limited Warranty.

Key Product Specifications & Technical Data:

• Brand: AEM Induction
• Part Number: 21-863C
• Product Type: Cold air intake system
• Vehicle Application: 2019-2021 Subaru WRX STI
• Engine Application: 2.5L H4
• Intake Tube Material: Mandrel-bent aluminum
• Filter Type: Washable, reusable, oil-free synthetic DRYFLOW filter
• Warranty: AEM Lifetime Limited Warranty

What's Included: The box includes the mandrel-bent aluminum intake tube, oversized AEM DRYFLOW synthetic air filter, custom heat shield, factory fresh-air duct connection components, and required installation hardware.

Features:

• Increased Airflow and Performance: Designed to improve intake airflow for enhanced horsepower, torque, throttle response, and engine performance.
• Oil-Free DRYFLOW Filter: Uses washable, reusable synthetic filter media that helps trap harmful contaminants while preserving airflow efficiency.
• Extended Filter Service Life: The oversized conical filter can support service intervals of up to 100,000 miles under normal highway driving conditions.
• Heat Shielded Intake Design: Includes a custom heat shield that helps protect incoming air from high engine-bay temperatures and connects to the factory fresh-air duct.

Fitments:
2019 Subaru WRX STI Base
2019 Subaru WRX STI Limited
2019 Subaru WRX STI S209
2020 Subaru WRX STI Base
2020 Subaru WRX STI Limited
2021 Subaru WRX STI Base
2021 Subaru WRX STI Limited

Air Freight Prohibited: false
Not Carb Approved: true
Carb Acknowledgement Required: true
Ltl Freight Required: false
Prop 65: Y
Part Type: automotive
Epa: N/A
Regular Stock: t
Units Per Sku: 1