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K&N Air Filters - Any opinions?

I hope that there aren’t already tons of discussions on this, but I searched and haven’t found any.

I’ve lately thought of going to K&N air filters for various reasons (throw away less stuff; save on air filters in the long run; maybe somewhat better performance and mpg are my thoughts).

Yet, I’ve seen mixed opinions including a “they’ll ruin your engine” thing.

The question is general and beyond my current vehicles (more of a “life” question) so I won’t bother to list my specific current vehicles.

Any experience / opinions?

great product, you have too clean them properly,at the intervals listed,biggest miatake made is the oil required,many people overdue it,if you have a dirt bike and are familiar with its maint(meaning air filter)youll be fine if not do not throw the directions in the garbage,put them in your glove box,and read them .

I have been using K&N for quite sometime. If you go with just the basic filter thats a very good buy. However I am not a fan of the complete intake kit that they sell.
As for any incremental improvement you will see depends upon the size and characteristics of your engine. Expect none, I went for it because of better filteration and a larger service interval.

Stock air filters filter the air better, provide sufficient air supply to get to the engine, and are cheap. The K&N supposedly increase power, but perhaps only very slightly, but they allow more dirt through the filter, into the engine, so over time increased engine damage may occur. IMHO, I’d stick with the stock filters. The cost difference isn’t that much over the life of a vehicle.

Go to for a real world air filter test.

correct dont expect any gains other than less cash in the long run,especialy with the stupid prices of filters nowadays,65.00 and they vary,but in the long run youll save alot,…if looked after properly


To breath better they have to filter less…You car uses 10,000 gallons of air for every gallon of gas. That’s a LOT of air. I’d want it as clean as it could be.

K,the air box only lets said amount of air into the box,via the feed tube,which is small,so the amount of air allowed in is more no less,OEM built that in.look at street bikes,take out the metered element the bike runs much better(but you have to match the air with fatter fuel mapping,hence(i hate that word) no more air,no more fuel,you just have a filtration device(that does just that.

save your $$ just change your air filter on a regular basis.

unless you are going to spend $$$$$$$$$$$$$$$$ on a ricer, and blow out the exhaust, add nitrous, and do all kind of other (useless IMHO) stuff, save the $$

Ok - I’ll throw in something about one current car then. I currently have a '97 Ford Escort (which means that none of my interest is really in tricking it out to be some high perf thing. I just try to maintain it really well) - and the filter in this car is a huge cone thing that is a) really expensive even in its disposable version and b) a total PITA to get in and out.

For this car, a cleanable filter will pay off pretty quickly in terms of $$ and if I have to pull it less will also save some aggravation.

I don’t know if that will change anyone’s opinion, but I’m still not only wondering about THIS car.

get the filter,

If you care about THIS car then only use stock paper element filters changed at proper times.
More air equals more dirt.
Access will still be a pain because you still have to pull the KN to clean and oil it.


It’s a good thing you’re not looking for performance because the conical filter you have is more than your car will ever need. The only thing on it that isn’t biodegradable is the rubber part. People like to spend money. It’s natural. If the money is saved, the person can get rich. Get used to having money in the bank and you won’t need the advice that you see here, but it is still wise to go to the experts or the experienced.

Most of the reputable testing I’ve seen shows that a properly maintained K&N filters filter about as well as a stock paper filter-- usually a little less well, but by a negligible amount. One study I saw even had the old fashioned oil-bath filter filtering better than anything else and flowing quite well. I suspect the reason why the manufacturers moved away from oilable air filters is that they have to make cars that can survive negligent owners. With a paper filter if the owner neglects it, it’ll just stop flowing, cause the car to run poorly at which point the owner will bring it in and replace it. With the oilable ones, if the owner doesn’t service it, it’ll stop filtering but he’ll still be able to go on his merry way, unaware of the engine damage being caused by ingested particles. Also, with the K&N’s, overzealous oiling by clumsy owners has caused airflow sensor failures.

For the record, I had a K&N filter on my '88 Buick Century for the last 50,000 miles or so of it’s life and my highway miles did seem to break 30 MPG more often. I kept a paper filter in the trunk though, and I would switch it in when I drove on dirt roads. For what it’s worth, I junked the car at about 230,000 miles due to body deterioration with an engine that ran like a top and didn’t burn a drop of oil.

The advertising greatly over sells it. It does have some potential to improve power and mileage, generally to a very very small amount. It also has a very real potential to damage MAFs or reduce filtering if you do not oil the filter just right.

Overall I would have to suggest that they are a very poor choice for almost any driver of a stock engine. Those doing serious performance changes to their engine may well do well with them.

I had one on a 1997 GMC truck, and on the highway, it would routinely get over 20 MPG. Over course, the engine had over 100K miles on it, so I always thought it was just “loose”. On the other hand, I had a 2004 Chevrolet truck with a K&N and it didn’t seem to make any difference. The stock filter on the 2004 was expensive, though, and that’s mainly why I used the K&N. Good luck.

I’ve had one in my old 89 Honda Accord for well over 250,000 miles. It works well if cleaned and oile properly (this means not to over oil it). I changed paper filter regularly before the K & N, so I really didn’t notice a change in MPG, but now I don’t have to buy paper filters . . . I guess I clean it every 15-20k. If I had it to do over I’d just buy and change the paper filters . . cheap and easy, no mess and no oil. Big increase in MPG? Not for me. The biggest contribution to increased MPG is that little nut behind the steering wheel . . . the DRIVER! I ALWAYS seem to get better MPG than EPA or other with the same car as I do . . . and I don’t drive like an old lady . . . I just think about what I’m doing and incorporate that into my driving. Rocketman

K,the air box only lets said amount of air into the box,via the feed tube,which is small,so the amount of air allowed in is more no less,OEM built that in.

Therefore…if it’s NOT letting in more air then you’re NOT increasing power.

I have used them for a few years on various vehicles, a Lexus, 2 Aleros, Ford Ranger, Malibu, & a Supra. So have friends. No probs and better performance. Mechanic warned my sister NOT to use it on her new (2007) Lexus because the check engine light would come on and the engine would be ruined. When she asked him why he said to just trust him. She is a rocket scientist at JPL so his answer didn’t satisfy her. She did use it because I have been using them on my cars, and she has had no probs for over a year, now. She likes the better pick-up she gets. One thing I do not do - I do not re-oil the filters after cleaning them. Don’t know if that’s a prob or not but for 4 years on diff vehicles there have not been any probs. I like 'em.

I’ve been employed for over thirty years at a major filter/filter system manufacture. And we tested K&N filters against our air filters and other competitors air filters. This is done to determine if there are market changes. But I won’t go into detail on how an air filter test is performed to determine the filter’s efficiancy.

But here’s what you do. Go up to any big-rig driver and ask if they have a K&N filter in the rig. They’ll look at you and say, “What? Are you stupid? I have a $3,000 turbo-charger I have to take care of!”