Best Engine Air Filters for Your Car

Your car’s air filter is key to the performance and long-term health of your engine. It is a critical element in your engine’s air intake system, allowing steady airflow into your engine while filtering out damaging particulates. The filter helps ensure that the pistons, cylinder walls, and sensors in your engine perform their best, reducing the chance of costly maintenance. An air filter can also optimize the amount of clean air flowing into your engine. Clean air is critical to the combustion process, which means your air filter can have a significant impact on your vehicle’s horsepower. That’s the muscle and acceleration we’re all looking for.

How is a reusable air filter different from a paper air filter?

Single-Use Paper Filters

The typical, restrictive air filter that comes standard with most cars is made out of pleated paper set into a plastic or foam frame. It’s low-cost, efficient and designed for one-time use. Most last roughly 12-15,000 miles under normal driving conditions and then need to be thrown away and replaced. Single-use, paper filters contain masses of tiny pores that block larger particles - dust, pollen, pollution - while letting smaller ones through. Over time, these pores become clogged, restricting airflow into your engine and reducing overall performance and efficiency. You might notice more slugging performance, slower acceleration and lower fuel efficiency. These are all signs that you may need to replace your filter.

Reusable High-Flow Air Filters™

K&N® High-Flow Air Filters™ are made from 4-6 layers of breathable cotton gauze that are pleated to increase surface area for increased efficiency and longevity. Their state-of-the-art design and naturally breathable properties allow for an increased flow of clean air into the engine — and that means increased horsepower and performance. This pleated cotton filter is then saturated with K&N’s trademark Red 201 Filter Oil™. The tacky oil is suspended within thousands of microscopic cotton fibers, trapping dirt and contaminants without blocking the pores of the filter. In fact, the oil not only traps unwanted contaminants, but those pollutants, now sticky with oil, begin to trap other particles, effectively becoming part of the filtration system. The result is a significant increase in the volume of clean air flowing into your engine - up to 50% more air than traditional, single-use filters.

Unlike single-use paper filters, K&N air filters are guaranteed for the life of your engine and come with a 10-Year/Million Mile Limited Warranty. The cotton filters are protected by a durable, epoxy-coated screen mesh and placed in a custom-poured and cured plastisol or urethane frame. Together they’re engineered to last for a million miles of use and never need to be replaced.

With regular cleaning using K&N’s propriety Recharger Kit™, your K&N filter can be reused time and again, performing virtually like new - a savings for both you and the environment. Assuming the average engine lifespan is 175,000 miles, you would need approximately 11 paper air filters over the lifetime of your vehicle. With a K&N air filter, you’ll only need one.

What are the pros and cons of different kinds of air filters?

Let’s break it down so you can choose the best engine air filter for your needs.

Disposable paper filters:

Pros: Affordability. In the short term, single-use air filters are your cheapest option. They last for 12-15,000 miles under normal highway driving conditions. For most drivers, that’s a full year of use. And paper is a fairly efficient filtering medium, blocking contaminants and keeping your engine healthy. That balance of affordability and relative efficiency is why disposable paper filters come standard with most vehicles. They’re also quick and easy to replace.

Cons: Airflow. While paper filters perform well when clean, they steadily lose airflow as the filter’s pores become clogged with dirt and particulates. At that point, airflow into your engine is increasingly restricted, undermining the performance of your vehicle. As we know, less airflow means less horsepower. For you, that means less acceleration and less muscle as you’re getting on the highway, hauling a heavy load, or traversing hilly or mountainous terrain. And that’s more than an inconvenience. It’s impacting your safety on the road.

Reusable Air Filters:

Pro: Long-term engine health. Lab tests show most K&N air filters are 97-99% efficient and they retain their efficiency for up to 100,000 miles depending on the size and shape of the filter.. Less dirt and particulates entering your engine, means better engine health, better vehicle performance, and fewer trips to the mechanic.

Pro: Engine performance. K&N’s® High-Flow Air Filter™ allows 50% more clean air into your engine. Its unparalleled balance of airflow and filtration efficiency helps your engine perform at its best. Assuming your engine’s already in fine working order, you can expect sustained horsepower and acceleration you can count on for years to come.

Pro: Durability. Originally designed for the racetrack, K&N Performance Air Filters® have been used in nearly every kind of elite-level motorsport, including Nascar. Here they undergo an entirely different level of testing not found in everyday driving. This gives K&N the confidence to guarantee its filters for with a Million Mile Limited Warranty and stand behind its products with a consumer protection pledge.

Pro: Maintenance. While standard paper filters need to be replaced every 12-15,000 miles, your K&N reusable air filter can go up to 50,000 miles before needing to be cleaned. That said, we do recommend you inspect your engine air filter annually or more often if you drive in dusty or dirty environments. This includes high-congestion highways.

Pro: Sustainability and long-term savings. K&N reusable air filters are designed to last the entire lifespan of your vehicle. On average that means you’ll need just one K&N air filter where you’d otherwise need 11 paper air filters. You will need to purchase K&N’s Recharger kit as often as needed to clean and maintain your filter. But in all other regards, your K&N filter is a one-time purchase and a long-term, low-cost investment in your vehicle’s health and performance.

Con: Cleaning. Maintaining your K&N reusable air filter is easy and cost-effective. But it does require a bit of time and the use of K&N cleaning products. You’ll need to remove the air filter from your engine and liberally spray it on both sides with K&N Power Kleen®. Wait ten minutes, then simply rinse off the accumulated dirt until the water runs clear. We recommend a cold, low-pressure water source (a gentle hose or faucet), not a pressure washer or garden hose nozzle. Allow your filter to gently air dry without fans or compressed air. Then thoroughly apply a layer of red filter oil and re-install in your engine. All together, cleaning your air filter is an easy, afternoon DIY, requiring little active time.

Follow easy-to-follow directions on how to clean K&N® High-Flow Air Filters™ watch this step-by-step video.

How do I find the right reusable air filter?

You’ve decided to invest in a reusable, high-performance engine air filter. Now how do you choose the right one for your car?

K&N produces a range of reusable air filters designed to suit the needs and unique fit of your vehicle as well as your performance ambitions. To find the right fit for your car, truck, motorcycle or ATV, start your search at KNfilters.com/airfilters. You’ll need to know your vehicle make, model, year and engine size to begin. In North America, that information can typically be found on the emissions decal under your hood. The make and model are proudly displayed on the rear of your car.

In Europe, your registration documents detail your engine size and vehicle type. That said, if you’re not sure whether your vehicle is single-point injection or multi-point injection, you should first consult your local dealer.

K&N also offers an array of specialty filters designed for industrial use, smaller engines, custom applications, crankcase vents, and high-performance racing environments. If you’re considering a filter for your custom application you’ll need to factor the shape and size of your air filter. Check K&N’s on-site FAQ under the sub-heading "Finding Products" for your guide to calculating the dimensions of your custom filter.

I am a freelance writer. I like writing since I was in college. I often write about automotive and technology topics. Other than that I also like to travel.