Air filters


Has anyone installed K-N air filters in their vehicles and actually noticed positive results such as they claim in their advertisements? Am considering investing in such and was looking for actual users.


on the old car talk forum this air filter was discussed and the thoughts were why bother…air filter is an air filter unless badly clogged they are all the same.


K&N passes more dirt than a plain old paper filter. Read test results on


They sure are fun to look at and if it was 1963 I would get one right away. I have seen the air filter on my pickup truck and it is almost a square foot in area. I can’t imagine wanting more airflow. Most of the filters are perfectly designed to get the right amount of warm air needed to prevent stalling and insure good gas mileage. If you have a Ford Van with a V-8, you really don’t need an aftermarket air filter. They look just like a KN filter element except for the paper look.


In short no. If you had a stock 1950’s car, they would give you some noticeable positive results or if you heavy modify one of today’s cars you might gain something. The simple fact is today’s cars are well designed and there is very little or nothing to be gained by messing with the air intake.

 On the other side of the coin, the K%N's require you to clean and re-oil the filter.  If you don't do the job just right you risk damaging your car (often the MAF) and in any case a freshly cleaned and properly oiled K&N will pass more  dirt than a stock filter.


If the K&N air filters were as good as they say, all the manufacturers would have put them in their cars at the factory. The fact they didn’t suggests that for an average stock vehicle, they don’t make a significant difference. Also, as already mentioned, the oil can cover the MAF, which is bad.


The K an N oil question is an interesting one, however this site simply list 3 opinions that the oil may interfere with the MAF. Has anyone at this site actually had a proven defectve MAF, where the failure was documented to be oil related?. I have had 2 K and N’s, and so far no problems. K and N’s web site addresses the issue, they not surprisingly deny any association between the oil and the MAF.

I use the air filter as it is cleanable, and apparently has good air flow. It is unclear if it increases MPG or horsepower, I am happy if it filters well.


I know the standard response for various fuel saving gimmicks here is “If its so great, it would be OE on every car”. But I do think you can explain this with K&N.

With a paper filter, if the owner doesn’t service it, it just stops flowing and runs poorly, wheras with an oil-based filter it’ll stop filtering and wreck the engine. New cars these days are designed considering that they may go without a lot of service and so an oilable filter wouldn’t really do for them.

Now some anecdotal evidence: about 6 or 7 years ago, I put a K&N in my 88 Buick Century. It did seem a little bit peppier and did give a very slight MPG increase, about 2-3 MPG on long trips I made regularly before and afterwards. It was also quite a bit noisier, which is what appeals to many, I suspect. I eventually junked the car due to other issues with a perfectly running engine after 230K miles with probalby about the last 75K with the K&N. Just to be safe, I kept a paper filter in the trunk and put it in on dirt roads and such.

Since then though, I’ve decided they’re not worth the bother and expense. They’re definitely hit-or-miss depending on the car, and I’d hate to spend 60 bucks on an air filter that might not make a difference.