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K&N RU-3870 universal clamp-on air filter delivers high airflow for racing vehicles radio-controlled cars generators snowmobiles tractors ATVs and more. Flexible 3-inch centered flange stretches up to 1/16 inch with 5-inch base 4.5-inch tapered top and 5-inch height fits any intake angle or offset. Pre-oiled cotton gauze media traps dirt while increasing horsepower and acceleration.
Key Features
- Engineered Power: Advanced media boosts horsepower acceleration overall engine response.
- Clamp-on flexible flange secures to 3in intake pipe.
- Stretches 1/16in for precise fit vibration absorption.
- High-flow cotton gauze outperforms paper filters.
- Universal design works on racing vehicles generators snowmobiles tractors ATVs RC cars any 3in flange intake regardless of angle offset.
Fitment
| Fitment Status | Universal or dimensional product |
|---|---|
| Required Verification | Exact dimensions, media, connection, mounting interface, and companion part number |
Specifications
| Brand | K&N Engineering |
|---|---|
| Manufacturer Part Number | RU-3870 |
| Product Type | Air Filters - Universal Fit |
| Fitment Type | Universal |
| Condition | New |
What's Included
One new K&N air filters - universal fit identified by manufacturer part number RU-3870. Hardware, adapters, clamps, hoses, filters, and service supplies are included only when stated for this exact product.
About K&N Engineering
K&N develops reusable air filtration, intake, oil filtration, fuel filtration, and related performance products for vehicle-specific and dimensional applications.
Related K&N Engineering Products
- Shop all K&N Engineering products
- K&N Universal Clamp-On Air Filter 3in FLG / 6in B / 4-1/2in T / 6in H
- K&N Universal Clamp-On Air Filter 3in FLG /4 1/2in B / 3 1/2in T / 4 3/8in H
- K&N Universal Clamp-On Air Filter 5in FLG / 6-1/2in B / 4-3/8in T / 8-3/4in H
Frequently Asked Questions
How do I confirm K&N RU-3870 fits my setup?
Match every listed dimension, flange or thread size, media type, mounting interface, and companion component. A similar shape or outside dimension alone does not confirm compatibility.
Is K&N RU-3870 washable and reusable?
Serviceability depends on the exact media used for this part number. Follow the K&N cleaning and oiling directions for this filter and never apply oil to media specified as dry.
What should be checked after installing K&N RU-3870?
Verify seals, clamps, fasteners, hoses, sensors, wiring, and surrounding clearance as applicable. Check for leaks or contact, then follow the manufacturer service and reinspection schedule.
Installation Instructions
- Clamp-on flexible flange secures to 3in intake pipe
- Stretches 1/16in for precise fit vibration absorption
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