Vehicle Fitment

• Universal Fit — Designed for performance vehicles, cold air intake systems, racing builds, and any application with a 3.50 in. intake requiring a large oval clamp-on tapered air filter

Fitment Notes

• This is a universal clamp-on filter with an oval (not round) profile — verify your intake tube outside diameter matches the flange inside diameter of 3.50 in. before purchasing
• Rubber flange can be stretched up to 1/16 in. (1.5 mm) to accommodate in-between sizes or angled intake configurations
• Note: this filter has a large 8.50 x 5.25 in. oval base OD — verify engine bay clearance in both horizontal directions before purchasing
• Not a direct OEM replacement for a specific vehicle — confirm fitment by measuring your intake tube diameter

Features

• Multi-layer oiled cotton gauze media delivers up to 50% more airflow than standard paper filters
• Oval tapered design provides superior filter surface area compared to a round filter of the same height
• Ultra-strong molded pliable rubber flange absorbs vibration and provides a secure, leak-free attachment
• Washable and reusable — requires cleaning only every 75,000 miles under normal conditions
• Pre-oiled and ready to install straight out of the box
• Rubber top end cap for a clean, secure finish
• Made in the USA
• Backed by K&N's 10-Year/Million Mile Limited Warranty

Specifications

• Shape: Oval Tapered
• Flange Inside Diameter: 3.50 in. (89 mm)
• Flange Length: 0.75 in. (19 mm)
• Flange Type: Centered (Single)
• Base Outside Length: 8.50 in. (216 mm)
• Base Outside Width: 5.25 in. (133 mm)
• Top Outside Length: 6.25 in. (159 mm)
• Top Outside Width: 4.00 in. (102 mm)
• Height: 5.50 in. (140 mm)
• Filter Material: Multi-layer oiled cotton gauze
• Filter Color: Red
• Top Style: Rubber End Cap
• Inner Wire: No

Included Components

• 1x K&N RU-5040 Universal Clamp-On Oval Tapered Air Filter

Product Description

The K&N RU-5040 is a high-flow universal clamp-on oval tapered air filter built for performance cold air intakes, racing builds, and high-CFM applications requiring a 3.5-inch flange with a large oval filter body. Its oval tapered profile — 8.50 x 5.25 inches at the base tapering to 6.25 x 4.00 inches at the top over a 5.5-inch height — delivers an exceptionally large cotton gauze surface area while maintaining a lower profile than a comparable round cone filter. This oval geometry makes it ideal for installations where horizontal clearance is generous but vertical space is limited. The multi-layer oiled construction flows significantly more air than any paper element, translating to sharper throttle response and measurable horsepower gains.

The centered 3.50 in. rubber flange mounts securely onto matching intake tubes, absorbs vibration, and can be stretched slightly to fit in-between sizes. Washable and reusable, the RU-5040 arrives pre-oiled and only needs cleaning every 75,000 miles under normal conditions. It is backed by K&N's 10-Year/Million Mile Limited Warranty and made in the USA — a reliable, long-term upgrade for any performance application requiring an extra-wide oval tapered filter through a 3.5-inch inlet.