K&N Filter Universal Air K&N RP-5161 Carbon Fiber Oval Universal Air Filter — Clamp-On, Oiled Cotton Gauze, Racing Use Carbon Fiber Top/Base Oval FLG. (8-3/4 x 3-1/4) 4-5/8H

The K&N RP-5161 is a universal clamp-on air filter built for high-performance and racing applications. It features an oval carbon fiber top and base with oiled cotton gauze filter media the same cotton gauze construction K&N has used for decades, now wrapped in a lightweight, rigid carbon fiber composite shell. The RP-5161 mounts via a centered oval flange with an inside diameter of 8-3/4 in × 3-1/4 in (222 × 83 mm) and a flange length of 2 inches, making it compatible with a wide range of custom intake tubes and velocity stacks in that flange size. Base outside dimensions are 18-3/4 in × 5 in; the overall filter height is 4-5/8 inches.

K&N Carbon Fiber Composites Series

The RP-5161 is part of K&N's Carbon Fiber Composites filter line a series developed specifically for racing and high-performance builds where strength-to-weight ratio matters as much as airflow. Carbon fiber composite construction provides outstanding structural rigidity at minimal weight, handles temperatures from below 0°F to 2,500°F at the raw fiber level, and delivers the visual appeal expected in a finished race car or show build. The process uses advanced composite techniques that control resin and fiber content to exacting tolerances the same methodology used in aerospace and motorsports components. The result is a smooth, glass-like finish that looks as good as it performs.

Important: K&N RP-5161 is designed for racing vehicles only. It is not legal for street use on emission-controlled vehicles and is not CARB compliant. It is not for sale or use on emission-controlled vehicles in California or other CARB states. Confirm your application before ordering.

Application — Universal Clamp-On Fitment

RP-5161 is a universal filter it is not calibrated for a specific vehicle make or model, and it does not bolt to a factory airbox. It is designed to clamp onto an intake tube or velocity stack that matches the oval flange opening. To confirm fit, measure your intake outlet: the flange accepts an oval tube with an outside perimeter that seats into an 8-3/4 in × 3-1/4 in inside oval. Flange length is 2 inches with centered positioning. This filter has been used in Chevrolet Corvette custom intake builds (2008–2013) and similar performance applications where an oversized oval filter is required.

Filter Media — Oiled Cotton Gauze

K&N RP-5161 uses layered oiled cotton gauze media, the same core filtration technology behind every K&N performance filter. The multi-layer cotton construction traps contaminants while maintaining high airflow the oiled media captures particles on contact while allowing air to pass with minimal restriction. The filter ships pre-oiled and ready to install. When the filter is due for service, it can be cleaned with K&N filter cleaner and re-oiled with K&N filter oil (2.04 oz / 60 ml required for re-oiling). The filter is fully washable and reusable not a disposable element.

Technical Specifications

Key Features

• Carbon fiber top and base: Lightweight composite construction with outstanding stiffness-to-weight ratio the same material used in motorsports and aerospace applications.
• Smooth, glass-like finish: Advanced composite process controls resin and fiber content to precise tolerances, producing a show-quality surface finish.
• Oiled cotton gauze media: Multi-layer construction delivers high airflow with effective filtration the foundation of K&N's performance filter technology.
• Clamp-on universal design: Mounts directly to any intake tube or velocity stack matching the oval flange dimensions no airbox required.
• Washable and reusable: Clean and re-oil with K&N service products; no disposable replacement elements needed.
• Pre-oiled from the factory: Ships ready to install, no initial oiling required.
• Large filtration surface area: Oversized oval format (18-3/4 in × 5 in base) delivers high flow capacity suited to high-displacement or forced-induction builds.

Installation Notes

RP-5161 clamps onto the outside of an intake tube using a standard hose clamp or intake clamp sized for the oval flange perimeter. The centered flange design allows the filter to be oriented in any direction relative to the intake tube. Confirm your intake tube's outside dimension seats within the 8-3/4 in × 3-1/4 in oval flange opening before installation. No factory airbox modification is involved this filter is intended for custom intake builds.

To service: remove the filter, apply K&N Power Kleen filter cleaner to the dirty side, allow to soak, rinse from the clean side with low-pressure water, allow to dry completely (do not use compressed air or heat), then apply K&N filter oil (2.04 oz) evenly across the cotton media. Allow 20 minutes for oil to wick before reinstalling.

Frequently Asked Questions

Is the K&N RP-5161 street legal?
No. The RP-5161 is designed for racing vehicles only and is not legal for use on emission-controlled vehicles. It is not CARB compliant and is not for sale or street use in California or other CARB-regulated states. If you need a street-legal K&N performance filter for a specific vehicle, use K&N's vehicle lookup to find a CARB-exempt drop-in or cold air intake for your application.

What intake tube size does the RP-5161 fit?
The RP-5161 uses a centered oval clamp-on flange with an inside opening of 8-3/4 in × 3-1/4 in (222 × 83 mm) and a flange length of 2 inches. Your intake tube's outer perimeter must fit within this oval opening. This is an unusually large oval flange it is not a standard round-flange intake filter. Measure your intake outlet carefully before ordering.

Is the RP-5161 washable and reusable?
Yes. Like all K&N cotton gauze filters, the RP-5161 can be cleaned with K&N Power Kleen filter cleaner and re-oiled with K&N filter oil. The filter must be fully dry before re-oiling, and oil must be fully absorbed before reinstallation. Required re-oiling amount is 2.04 oz (60 ml).

Does the RP-5161 come pre-oiled?
Yes. The filter ships from the factory pre-oiled with K&N's red filter oil and is ready to install out of the box. No initial oiling is required.

What vehicles does the K&N RP-5161 fit?
The RP-5161 is a universal filter with no vehicle-specific fitment. It is used in custom intake builds across a wide range of performance applications. One commonly noted fitment is the 2008–2013 Chevrolet Corvette with a custom intake using this oval filter configuration, but the filter itself is not vehicle-specific it fits any application where the intake tube matches the oval clamp-on flange dimensions.

What is the difference between the RP-5161 and a standard K&N round air filter?
The RP-5161 is an oval filter rather than round, making it suitable for space-constrained or aerodynamic intake designs that cannot accommodate a round filter. The carbon fiber top and base add structural rigidity and reduce weight compared to standard metal-capped filters. The oval format also increases filtration surface area compared to a round filter of similar height, which is beneficial in high-flow race builds.

What warranty does K&N provide on the RP-5161?
K&N covers the RP-5161 with a 1-Year Limited Warranty against defects in materials and workmanship when the filter is installed and maintained per K&N's guidelines. For warranty service, contact K&N.

Can the RP-5161 be used with synthetic oil?
Yes. K&N cotton gauze filter media is compatible with conventional, synthetic, and blended motor oils in the engine. The filter media itself is oiled separately with K&N filter oil not engine oil and that product is also compatible with any engine oil type used in the application.