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K&N

K&N 33-2231 High-Flow Air Filter

K&N 33-2231 High-Flow Air Filter

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✔ K&N Engine Air Filter 33-2231 — High Performance, Washable, Premium Replacement Filter
✔ Fitment: BMW 1996–2007 L4/L6 engines (325Ci, M3, X3, 320Ci, 320i, 325Ti, 330Ci, 318i, 323i, 328i, and other select models)
✔ Direct replacement for OEM air filter — no modifications required
✔ Increases airflow up to 50% more than standard disposable paper filters for added power and acceleration 
✔ Washable and reusable — engineered to last for the life of your vehicle 
✔ 10-Year / Million Mile Limited Warranty — the last filter your vehicle will ever need 

 

K&N 33-2231 High-Flow Air Filter — for BMW 3 Series and X3

A clogged or dirty air filter can reduce vehicle acceleration by up to 10% and restrict engine performance. The K&N 33-2231 replacement filter increases airflow to the engine while providing exceptional filtration . Unlike disposable paper filters, this K&N filter is washable and reusable, saving you money over the life of the vehicle and reducing waste.

This high-performance panel filter features layered, oiled cotton gauze media designed to trap harmful contaminants while maximizing air flow. The filter is pre-oiled and ready to drop directly into your existing factory air box, making installation simple . The durable frame and media are designed to provide up to 50,000 miles of service between cleanings under normal driving conditions.

 

 

When to Replace

• Reduced engine power or sluggish acceleration
• Decreased fuel economy
• Visible dirt, dust, or debris accumulation on the filter
• Filter has been in service for 50,000 miles or more without cleaning
• You want to upgrade the performance of your vehicle

Product Details & Highlights

• ✔ Increased airflow — provides up to 50% more airflow than disposable paper filters • ✔ Washable and reusable — designed to last for the lifetime of your vehicle • ✔ Easy installation — pre-oiled and ready to drop into your factory air box • ✔ Save money — avoids the cost of replacement disposable filters • ✔ Eco-friendly — reduces waste by avoiding disposable filters • ✔ Race-tested — the Official Air Filter of NASCAR, trusted on the racetrack • ✔ Backed by K&N’s manufacturer warranty

Package Contents

• 1 × K&N 33-2231 air filter (pre-oiled)
• 1 × Foam pad (for dust protection)

FAQ

FAQ

Is this an OEM replacement or an aftermarket part?
This is a high-performance aftermarket replacement air filter, designed to fit directly into your factory air box as a drop-in replacement .

Does this fit my 2002 BMW 325i?
Yes — the 325i with the L6 2.5L engine is listed as compatible. We recommend verifying your specific model and year before ordering .

Does this fit the BMW X3?
Yes — the X3 (E83) with 2.5L and 3.0L engines from 2004–2006 is compatible .

Can I use this filter on a different BMW model?
This filter is designed for a wide range of BMW 3 Series (E46) and X3 (E83) models. Please verify your specific application before ordering.

How often should I clean this filter?
Under normal driving conditions, the filter can go up to 50,000 miles before cleaning is required .

Does this filter come pre-oiled?
Yes — the filter comes pre-oiled and ready to install .

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