K&N High-Flow Universal Clamp-On Air Filter RU-5111 — 3" Flange, 5.75" Height, Washable High-Performance

K&N RU-5111 is a clamp-on, washable high-flow air filter with a 3-inch flange and 5.75-inch height built to increase airflow and last the life of your vehicle.

This universal clamp-on filter from K&N delivers a simple swap-in upgrade for many engines and aftermarket intake setups. Constructed with multiple layers of premium cotton gauze media and a pliable molded rubber flange, the RU-5111 is engineered to improve airflow while trapping contaminants. Because it is washable and reusable, the filter reduces disposable-waste and lowers long-term maintenance costs compared with single-use paper elements.

How does the RU-5111 improve engine performance?

The RU-5111 uses a multi-layer cotton gauze media treated to attract and hold dirt while allowing increased air volume to pass through. More airflow to the intake can help the engine breathe better during acceleration, providing smoother throttle response and potential gains in power when paired with compatible systems.

• Four layers of cotton gauze for improved flow and filtration balance
• Specially designed tacking agent on the media enhances contaminant capture
• Pre-oiled from the factory to optimize performance right away
• Works with many clamp-on intake and breather applications

Will this filter fit my application and how do I mount it?

The RU-5111 is a universal clamp-on design intended for flexible fitment across many engines and aftermarket intakes. The filter features a 3-inch flange diameter, 0.75-inch flange length, and a 5.75-inch overall height in a round tapered (cone) shape for common clamp-on connections.

• Flange diameter: 3.00 inches and flange length: 0.75 inches for clamp or hose attachment
• Round tapered shape fits many cone-style intake openings
• Pliable molded rubber flange absorbs vibration for a secure seal
• Simple clamp installation—no special tools required for most setups

How often does the filter need cleaning and what is the maintenance process?

K&N recommends cleaning the element only when needed; under typical highway conditions this is about every 75,000 miles. Maintenance is straightforward: remove, wash with a K&N-approved cleaner, rinse, dry, and reapply filter oil before reinstalling.

• Cleaning interval: approximately every 75,000 miles under normal highway use
• Use K&N cleaning kit or equivalent products for best results
• Allow element to fully dry before re-oiling to maintain filtration integrity
• Reusable design eliminates frequent replacements and reduces landfill waste

What does the RU-5111 offer in terms of durability and warranty?

The RU-5111 is built with durable materials and modern manufacturing to stand up to repeated cleanings and long-term use. K&N backs the product with a one-year limited warranty and manufactures it in the USA for consistent quality control.

• Rugged construction: premium materials designed for lifetime use
• Pre-oiled and ready to install straight from the box
• 1-year limited warranty for covered defects
• Made in the USA with established quality standards

Who is this for? The K&N RU-5111 is aimed at drivers, hobbyists, and mechanics who want a reliable, reusable clamp-on intake filter to increase airflow and reduce long-term costs. It suits owners of custom intakes, older vehicles, small engines, and anyone seeking a durable cone-style element with straightforward installation and infrequent maintenance.