AEM 21-856C Cold Air Intake for 2017-2019 Subaru Legacy 2.5L

Vehicle Fitment

• 2017-2019 Subaru Legacy (2.5L H4 naturally aspirated gasoline)
• Includes Legacy 2.5i, 2.5i Limited, 2.5i Premium, 2.5i Sport trims

Features

• Performance cold air intake system tuned for Subaru Legacy 2.5L H4
• Dyno-tested to improve airflow and increase horsepower/torque over stock
• Oversized AEM Dryflow synthetic washable air filter - no oil required
• Mandrel-bent aluminum intake tube with gunmetal gray powder-coat finish
• Heat shield protects filter and helps reduce intake air temperatures
• Designed to work with factory emissions components like MAF sensor and breather tube
• Improves throttle response and engine sound character
• Limited lifetime manufacturer warranty

Specifications

• Part number: AEM 21-856C
• Application: Cold air intake system
• Fitment years: 2017-2019
• Vehicle: Subaru Legacy
• Engine: 2.5 L H4 naturally aspirated gasoline
• Estimated horsepower gain: ~5.8 HP @ 5800 RPM
• Air filter material: non-woven Dryflow synthetic, washable & reusable
• Replacement filter: AEM 21-2027DK
• Clamps included: 3 stainless steel worm-gear clamps
• Couplers included: 1
• Intake pipe material: aluminum, gunmetal gray finish
• Street legal: **Not legal for sale or use in California on pollution-controlled vehicles**

Included Components

• 1x AEM Dryflow synthetic air filter
• 1x Mandrel-bent aluminum intake tube
• 1x Heat shield
• 3x Stainless steel clamps
• 1x Coupler
• Mounting hardware kit
• Installation instructions

Product Description

The AEM 21-856C Cold Air Intake System is a performance-engineered induction upgrade designed specifically for **2017-2019 Subaru Legacy models** equipped with the naturally aspirated 2.5 L H4 engine. This intake system replaces the restrictive factory air filter assembly with a high-flow, mandrel-bent aluminum intake tube and oversized AEM Dryflow synthetic air filter to increase the volume of cooler air entering the engine, which can result in improved throttle response and measurable power gains over stock setups. The included heat shield helps insulate the filter from hot engine bay air to further improve air density and performance.

AEM's Dryflow synthetic filter media delivers excellent filtration performance without the need for traditional filter oil, and it's washable and reusable for long service life - up to approximately 100,000 miles between cleanings under typical conditions. The system is easy to install with all necessary hardware included, and it's engineered to retain the use of factory emissions connections such as the mass airflow sensor and breather tubes. While this intake is designed for a direct fit on compatible Legacy models, it **is not legal for sale or use in California** on pollution-controlled vehicles - confirm your local emissions compliance before purchasing.