K&N

[70Sixter]

A number of folks have reported MAF problems after K&N. Some obviously over-oiled their filters after cleaning them. Others said they just took them out of the box and installed them.

One post recommended wrapping newspaper around the filter to absorb any excess oil.

Not sure there is a definitive answer about where proper amount of oiling prevents K&N problems.

I would not put one in my Box. I do have one in my 914.

[mikefocke]

install an air filter that, in objective tests, allows more particles and bigger particles into the airflow into your engine?

Don't you use an air filter for only one reason...that being to keep dirt out of the engine and reduce wear?

[Jaxonalden]

If that were fact, K&N would be committing false advertising. I haven't heard of any lawsuits? Have you? If it were such a bad product how come people still buy them? The company seems to be doing great business for having a terrible product, don’t you think? .

In the forties, cars used an oil bath filter. The air would go through the oil before getting drawn into the engine, cleaning out any dirt particles. The same principal holds true with a K&N. I can't see how a dry paper filter can clean air better than a filter with sticky oil being held in a cotton media catching the dirt.

But to each his/her own.

P.S. To the post above, yes the auto filters are sparingly pre-oiled.

[dmcutter]

I just put a K&N filter in my Kawi a month or so ago. Noticeable improvement, but then again the stock filter was pretty thickly covered with bug parts. But I digress. The filter was preoiled from the factory. Don't they preoil the car filters too? I seemed to be done quite sparingly...

[aussieboxy]

Have had mine installed for over 60,000ks that's about 40,000 miles I think & no problems at all. Light oiling is the key

[cnavarro]

The '99 I just bought had a MAF failure at only 35,000 miles (Sept '08) - car has had a K&N in it from the start. It was cleaned and re-oiled at 30,000 last year at 30,000, per the dealer notes. The first thing I'm doing is putting in a fresh paper filter. From the many used oil analyses I've done on various customer cars, I've found that silicon levels (dirt, contamination) are about double for engines running a K&N filter. The only cleanable air filter I have seen that doesn't allow more contaminants in are the oiled foam filters - there are a few out there. For reference, here's just one comparo of foam versus k&n:

http://www.smartsynthetics.com/articles/amsoil_vs_kn_two_stage_air_filter.htm

Sorry to post an Amsoil link, but it's the first one I found in Google.

The best foam air filters are those made by ITG:

http://www.itgairfilters.com/

Another good link to read up on air filter testing is:

http://www.bobistheoilguy.com/airfilter/airtest1.htm

K&N does offer foam pre-filters for some filter types, which would bring their performance up to par with other filters. But just changing your paper filter more often will yield roughly the same performance (at a greater cost of course over the lifetime of the car if you don't count MAF failures with over-oiled K&Ns).

[mikefocke]

and because it doesn't have lawsuits against the company that makes the product is no reason to assume the product is any good. The purchasing may be due to marketing (and K&N has done a lot of it over the years). And the lack of lawsuits may be due as much to the difficulty of proving the cause and damage as for any other reason. Damage from the increased abrasion would occur over many years. How would the lawyer prove how much of the wear was the portion caused by the dirty oil that was caused by the difference in filtration?

The comparison test I saw was in a magazine about 2-3 years ago. Amsol's tests came up with the same results.

Charles' oil samples testing only confirms what these other two tests have shown...the K&N when properly oiled lets in more particles of dirt and bigger particles of dirt.

If you want to install one because you think it sounds "cool" to have one...it is your car, your money and your choice. Or if you value a few HP over increased wear, then that is a valid argument for you. Or if you use the car on the track and your class allows the change, that too can be justified by the tests.

But don't kid yourself that it is the best air filtration device you can fit to the car to filter dirt from the air and keep it out of the engine.

If you have one, change your oil much more frequently (which will cancel out and advertised reuse savings in using the K&N).

There are some additional test results in this link