K&N filters on a street engine?

[Keeper]

Okay I finally tracked down the air cleaner I wanted for my bucket. Of course they offered to sell me a K&N filter to fit the new cleaner.

I have heard before that K&N on street engines are a no-no no matter what they tell you due to gunk getting into the engine. Drag engine sure as they are torn down regularly.

I have searched and of course found arguments on both sides of the fence.

So engine gurus, whats the scoop? K&N on street yes or no?

 

[Mike J]

I've run them in my street cars and motorcycles for the last 15 yrs., no problems. They're washable and as long as you clean them regularly and spray them with the air cleaner oil, you shouldn't have a problem. If you are in dustier conditions , clean it more frequently.

 

[benT]

Keeper: Like you said, there are a lot of opinions on this. I've personally run genuine K&N's on the last three daily drivers I've had ('89 Mustang Gt, '01 Ford Focus, '06 F150 5.4); all have/had well over 100K miles with them with no engine issues. I clean the elements well, let them totally dry, oil them and let them fully dry again. No issues with Mass air air sensors or any of that. My '27 has an exposed pair of them on on my dual quad set up. If I used a conventional on my '27, I'd be replacing a lot of front filters!

 

[Keeper]

Good to know. I think some of the issues I have been reading about were caused by knock off filters.

 

[RPM]

Take a brand new K&N filter and hold it up to the light, and look how big the holes are in it. Small birds could get in the engine. They will flow a lot more air than a stock filter, but will also let in more dirt. I know when I worked in the diesel shop, Cummins would void a warranty claim for worn pistons or rings if you had a K&N in the truck.

 

[vand]

We found out a long time ago A standaed filter with a sock cover is far superior to K&N filters on dirt track race cars. As RPM stated the K&N filters allow way too much dirt to enter the motor.

 

[Screaming Metal]

As Ron said, hold it up to the light....and look mostly at the pleats sewn into the upper and lower sections, and then at the crease in the pleats. Usually about 1 in every5 you'll find small leaks in them.
I liked K&N since the early days....I don't give a damn who makes them, if they're bad then they're bad. Just don't simply bolt on one without checking it out first....
ESPECIALLY on a blown / turboed motor.

 

[Screaming Metal]

Let me also add that there are alot of other MFG'ers that are Good and don't produce as many leaks, but still check them all. AFE, Holley, Fram, Purolator, are among a few.
The foam Pre-filter also helps, The best ones are lightly oiled, though they don't look as good. K&N's, as long as they are checked, are fine.

Just, before you spend your hard earned money getting a life warranted reusable filter, hold it up to the light and check it.
First time you See yourself one of these leaks.....you'll always check that again everytime.....

 

[Mike]

Take a brand new K&N filter and hold it up to the light, and look how big the holes are in it. Small birds could get in the engine. They will flow a lot more air than a stock filter, but will also let in more dirt. I know when I worked in the diesel shop, Cummins would void a warranty claim for worn pistons or rings if you had a K&N in the truck.

That was always my line about K&N-style filters, Ron. They are designed to stop small birds and beer cans, but not much else. I've seen leakdown test results that prove paper outperforms oiled gauze, every time. For those who think oiled gauze filters are the bees knees, apply a small, light smear of grease below the element and see how much grit the grease collects in a couple weeks drive time.

At one point, K&N was stating their products worked within 99% of paper filters, so even they were admitting their stuff was not as good.

As Ben stated, when it comes time to service a oiled, gauze filter, oil needs to be applied sparingly and then the filter needs to sit, in order to absorb as much of the oil as possible. And may angels protect the new users, who simply oil their filters too heavily, because that oil will be drawn into the intake tract. And turbocharged motors pull even more oil out of the filter, hence the warnings from many diesel manufacturers. Add in a mass air flow sensor and you're going to be looking at replacing it.

The bottom line for me is when the major manufacturers have all issued technical service bulletins about oiled gauze filters, then there must be some issues with them, yes?

 

[Keeper]

Thanks for the info. I will stick with my paper filter.

So that begs the next question. Who makes a good paper filter?

 

[Screaming Metal]

My bet has always been Fram, stick with a quality filter. Wix are also good, and for less money. AC would be my next one. Those 3 make about anything you'd want. There are also several other good makes....look at how its made, and its warranty.
Lifetime warrantys say alot, also get your finger and press against the pleats. Better quality ones will usually have a support screen on the inside and a warranty of several thousand miles for the paper ones, and lifetime for the reusable ones....
Not all aircleaners are the same. There is alot to be said about the ones that are burn resistant. If you've ever been in on a good carb fire....you know what I mean! All it takes is one good backfire thru the carb.

 

[Screaming Metal]

Oh, before I forget....Mr. Gasket makes some decent ones, Holley also. There are several places on line were you can download a cross reference chart on your aircleaner elements.
Not all of them flow the same either....

 

[Keeper]

Thanks always nice when a thread like this does not turn right into a bitch fest!

I always leaned toward FRAM but with the oil filter issues, (I have switched to WIX for everything), I was not sure how the air filters stacked up.