When you have your car’s oil changed, assuming you don’t do it yourself, do you continually replace the paper air filter, or have you invested in a K&N permanent air filter? When switching out the paper air filter to the K&N in my new Subie today, and driving it afterwards, I was reminded why I think a K&N is the only air filter choice:
1–It will pay for itself on a cost alternative basis
They run either side of $45 on Amazon, depending on the model you need, and the K&N Site will help you there. Even if you buy your own air filters, it won’t take many replacements to offset the cost of your K&N. You’ll have to buy some oil for it at some point–that’s what acts as a fine filter–but K&N recommends you clean and add oil about every 50,000 miles.
2–It may pay for itself over time in improved fuel economy
The K&N will improve your fuel economy, it has to, as the air always flows freeer to the engine through the (clean) K&N, which means you will depress the accelerator slightly less to achieve the same speed as you’d have with a paper filter. In the Toyota Sequoia it gave me just under 1 mpg difference in town, no measurable change on the freeway. TBD for the Subie.
3–It will increase your horsepower output
Same as above. You will get, and you WILL feel it (I have already today), a little more ummph from the engine than with the paper filter. This will be most evident in low inertia driving (around town).
Disadvantages? None that I can think of, other than a larger outlay up front rather than a series of cheaper paper filter replacements. Cry now, smile the rest of the time. Get yours direct from K&N, through Amazon, or at most auto parts stores and departments.
I think the newer the vehicle with the more chip based fuel systems, the less the K&N will do for mileage. The Sequoia is a throttle body system so I could see some gain there. The newer vehicles are so sophisticated the air/fule mixing may counteract and compensate for the lack of free air flow from a paper filter. Still, you should at a minimum feel a little more power, and it will certainly pay for itself sooner than later. We use it in every vehicle. The make oil filters too, and I’ve never seen the advantage of these over any of the common brands.
Probably the most common users of the K&N are the speed guys; I’d guess the majority of BWM enthusiasts use them. K&N is a speed company by heritage.
Doc, try it in the Tesla and report back 😉 Actually it would be a great replacement for the Sub air filter.