Audi S4 Air Filter - APR - High Flow, Cotton-Gauze - 2004-2009. This direct drop-in filter upgrades your B6/B7 S4 factory airbox to improve airflow while keeping filtration effective.

Built with APR proprietary cotton-gauze media, this reusable element increases flow and lowers pressure drop compared to typical paper filters. Flow-bench refinement supports efficient breathing, helping sharpen throttle response and add a richer intake note without committing to a full intake system. It is compatible with factory emissions equipment and suits stock or modified setups, delivering consistent performance with routine cleaning and re-oiling.

Features

• High-flow, cotton-gauze filtration media
• Washable and reusable with normal maintenance
• Flow-bench optimized for efficient airflow
• Lower pressure drop than stock
• Direct drop-in for 2004-2009 Audi S4 factory airbox
• Works with naturally aspirated and forced-induction setups
• Maintains compatibility with factory emissions equipment
• Subtle enhancement to intake sound and throttle response

Have questions or want expert guidance? Call our team. We serve enthusiasts at our Austin, Texas and Los Angeles, California area locations, where we offer professional installation and customization. Texas: 512-982-9393, California: 562-981-6800.

Thinking about purchasing multiple items? Contact us for shipping discounts.

We install on premises at both locations.

CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov