Do Performance Air Filters Really Give You Any Power Gains?

Performance air filters are billed as a cheap and easy way to add horsepower to your car, but do they really work? Engineering Explained wanted to find out so they pitted standard OEM filters against a low cost aftermarket filter and a K&N performance filter.

To conduct the test, the YouTube series installed the filters on a Subaru Crosstrek and then made multiple runs on a dynamometer. This allowed them to determine the horsepower and torque changes attributed to each filter. They also used a VBOX to measure real-world acceleration changes.

Without further ado, the dirty OEM air filter enabled the car to produce 158.25 hp and 137.25 lb-ft of torque. When the clean OEM filter was installed, the dyno showed the car produced 160.10 hp and 137.43 lb-ft of torque – a minor increase of 1.85 hp and 0.18 lb-ft.

The aftermarket CarQuest filter was actually kind of surprising as it did better than the clean OEM filter despite costing less. According to the dyno, the filter enabled the engine to produce 163.32 hp and 140.82 lb-ft of torque. This is 3.22 hp and 3.39 lb-ft more than the clean OEM filter.

Lastly, the K&N filter was installed and it allowed the engine to produce 164.42 hp and 142.53 lb-ft of torque. This was the best performing filter, but it was only created 1.1 hp and 1.71 lb-ft more than the cheap aftermarket filter.

Those are some pretty small gains, but are they noticeable in real-world driving? The differences between the clean and dirty OEM filters were negligible, but the cheap aftermarket filter did improve acceleration times by approximately 1.2 percent. The K&N filter fared better as acceleration times improved by an average of 2.74 percent.

While it’s clear that non OEM filters did improve performance, there’s a question of whether they are worth it. A quick check reveals a K&N filter for the 2018 Subaru Crosstrek Premium costs $49.99 and that seems a little pricey considering the minor performance gains.

 

  • Mind Synthetic

    NO, unless you are ruining insane turbo set up you dont need one

  • Jason Miller

    The main reason you buy something like the K&N is so that you can use it, clean it, use it some more, clean it again, and keep using it instead of having to buy a new filter over and over again. That alone makes it worth it.

    • clueless economist

      I have 263k miles on my Tundra. I installed a k&n at 25k miles. $50 once.

    • bryceee

      Better Induction Sound as well.

  • Kagan

    Well it is easy to have less restriction through the filter but does it filter the same?

    Why were the clean oem slower despite giving more on the dyno?

    The dyno it self has inaccurancy so you should at least take the average value not the best value.

  • Craig

    Are ‘performance filters’ allowing more unfiltered air into the engine?

    • pcurve

      Yeah, I never really understood why people assume that K&N would know better than car mfr. to extract more power of engines without sacrificing long term reliability.

      • Craig

        I’ve always thought that. As if car manufacturers wouldn’t use ‘performance’ type filters on all of their cars. To hear K&N tell it – there is nothing but positives using their product.

        • brn

          Manufacturers take a lot of shortcuts. Have you looked at stock speakers in “premium” sound systems?

          A decent performance filter is able to pass more air, because it has more surface area. The amount of air per square inch is not higher, so the filtering capabilities are as good.

      • Matt

        While that question of reliability & performance should be taken into consideration, my take, and I think the majority of others is: 3rd party products, be it performance or other, can do/are better because the car manufacturer decided to save money on x part. And for those who care have better 3rd party options for a price. Let’s say the hi performance air filter works 2% better in hp & longevity at a cost of $5 more to the manufacturer over a standard filter. Yet the brand sells 500k of that car a year. A savings of $2.5m. Might not seem like too much to a multi billion dollar company but there’s dozens if not hundreds of other components in the car that if the engenners/designers had their ways would just cost the mfr a few dollars more. But if all included would end up costing the car brand exponentially more.

        It’ll always be a battle of best engineering vs cost and what the brand wants to emphasize over the other.

        • Craig

          A very sound argument Matt.

        • javier

          right but dont all manufacturers use a paper filter vs the k&n cotton pleated type for noise issues. If porsche could get 2 hp and have to pay only a hundred bucks it would

          • Matt

            I do believe I’ve seen some cars that have had k&n type filters from stock. Though they’ve been special editions.
            I was more generalizing & not specifically addressing air filters… that usually there are better 3rd party options for performance, reliability, fit & finish/materials or a combination of those at a cost to ones that want it. Idk if Porsche makes their gt cars air filters best quality, price not a concern. The analogy I’m thinking of it like is: one can get a Porsche GT2 RS with normal paint or you can spend $10k+ on Porsches special paint if one wants the best quality paint on their gt2rs. Many variables go into play on the company side & what the consumer wants/will buy.
            Many car companies have in-house tuners that you can buy parts to make your car perform better than stock so at least some parts of what they put on their cars to begin with were not the best it could have been at least in pure performance. (sometimes involving a less comfortable ride or other drawbacks)

  • I’M GLAD I DIDN’T HAVE TO WATCH ONE OF HIS LONG DRAWN OUT VIDEO’S FOR THE ANSWER.

    • Loquacious Borborygmus

      TL;DR.

  • General. Koofta

    plus the added bonus of having to replace the expensive filter MORE OFTEN as it loads faster!

    • Jason Miller

      You know K&N filters are washable, right? You don’t throw them away. You clean, re-oil and re-use.

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