924Board.org

[8trdrvr]

im starting to agree with you larso and one of the above posters.

it seems as though the paper is 'fool' proof. Restrictive, yes, but it WILL NOT allow debris to get to the intake. Id rather have the restiction than me forget(MY LUCK!) to oil the filter and let it do damage to my engine by letting stuff through cause i missed a maintence cycle on it. I love my 924, but the airfilter in it is not always on my mind! you guys all have great points. thanks for the posts!!!
Kevin

[numbers]

What? A louder muffler doesn't make it go faster? I suppose the next thing you are going to tell me adding a wide body and 40 pounds of subwoofers that rattle the windows don't make it any faster either. Bah, humbug.

[Diesel]

Who says a paper filter is restictive? And why would a foam filter loaded with oil be less restictive? Don't believe everything you hear.

[-nick]

the K&N's do actually do their job and flow more air. my parts shop has a cool little test setup where you can measure the flow between the K&N and stock filters. but of course, like everyone's said, a better flowing filter doesn't make any difference on these engines.

-nick

[larso]

This may be an uppage in flow, but also an uppage in dirt, causing less HP, or equal HP. I think on drag tracks, and race tracks, they may be worth it...All these HP tests done on the K and N filters are done in impractical situations. For example a closed garage, or a dyno. But on a street car, there are always dirty roads, or windy, dusty days. The oil on the filters encourage dirt to sit on the filter, and then when you do a WOT acceleration, this oil may get sucked right into your engine. If not the oil itself, the little pieces of dust hanging on the edge of the filter, kind of like a weak magnet. I know for sure that when the oil coming from the separator gets trapped on the air filter, the oil gets sucked right off the filter.

Are these dyno tests, and flow tests on the K and N's done on newly oiled, newly bought filters, or used filters with lots of miles and dirt trapped on them? I'll bet after a certain number of miles they lose their flow...this causes a person to clean their filter more often, and buy more K and N cleaner/oil...wallet goes empty.

The marketing tactics of these K and N's are really easy to see through if you use you head.

[Richard]

Wait a minute! There is no evidence I've seen that shows there is an uppage in the amount of dirt that can get through a KN just because it passes more air. If everyone would just kindly visit their site (ww.knfilters.com) you could learn a whole lot and make your opinions on what the manufacture says, not on conjecture and hearsay. Look at the published info and make an informed decision please. Not all companies have marketing ploys to rob our dollars. Some may actually have a superior product. If you can change your oil, than you can oil your filter on time too! That's what logbooks are for. Why is it we can spend a jillion hours under our cars and half a jillion hours on this site and not spend a minute to create a logbook that tells what has been done and when?

[larso]

From K and N site: "7. Can an engine get too much airflow?

No, an engine can only take in a fixed volume of air depending on the engine’s size. The more restriction that an air intake system (filter, air box, and tubing) causes, the greater the potential is for power and mileage degradation. "

No offence but their site is full of horse/donkey-doo-crap. The statement: an engine can't get too much flow; is amateur, and immature (kinda a cool pun). The only time you need more flow is if you have more rpm and want high RPM power. If your engine only displaces 2.0 litres, extremely large intake pipes and exhaust pipes will cause you to lose power, unless you run 20,000 RPMs to make use of the extra flow.

6. Will a K&N filter cause my vehicle’s mass air sensor to fail?

"No. A properly oiled K&N filter will not contaminate a mass air sensor. However, if you over oil your filter it is possible for oil to drip off the filter and contaminate the sensor. In the last few years certain vehicles have had design problems with the mass air sensors. Some local dealers have attempted to blame the problem on a K&N filter, however, of all the sensors we have sent off to be tested we have yet to find one that failed due to oil contamination. The defect in all cases was within the mass air sensor unit. If oil were to contaminate the sensor’s “hot wire”, the wire itself could be cleaned, however if there were a problem with internal circuitry the sensor would have to be replaced. "

How about that...if you don't keep you filter in PERFECT order, it will cause damage to components. Who's to say that a 6.0 litre engine doesn't require less oil on the filter than a 2.0 litre engine? The 6.0 litre engine sucks in more air fast, so might suck in more oil off the filter. How would any reasonable human being know if he has overoiled his filter? You can't measure how many "milliliters of oil" to put on you filter, and just judging by eye, it's impossible to know if you have over or under oiled your filter.

Different engines put out different displacements...does it say on the oil bottle "only put this amount of oil on the engine if your intake pipes are this size, and your engine is this size". There's too many possibilities and science involved to use a K and N filter correctly.

When paper filters get dirty, they get more restrictive. When K and N filters get dirty, the oil gets heavier, and may even drip off. How about operating temperature? who's to say that K and N oil doesn't get thin at a certain temperature and slip through the filter? On their "tests" they have ideal conditions. On a dyno in a garage, you don't have high summer temperature, turbo temperature, etc. Paper filters are not responsive to heat! wet oil is!

I'm not trying to beat a dead horse, but everything that K and N claims seems to be defendable if you THINK about it...

If I was trying to sell a product I would do just the same as K and N does! Do all tests on a clean filter, in perfect conditions. Don't bother trying a hot running car that hasn't been bled, on a hot summer day... Lots of 924 owners have these common problems all the time and I bet the K and N oil gets thin and seeps through!! Where are the tests on the site that prove that dirty hot oil on the filter will not drip off and get sucked into the engine? Oil attracts dirt, then when it's hot gets blown around all sorts of places.

Anyways I know some people will never change their mind so I'll stop nagging now hehe.

[Rick MacLaren]

I know a lot of guys who run them on their 951's, but they're keeping them in good shape and oil them up every season.

[Lizard]

ok you people who think that k&n do nothing are ID-10-T the k&n air filters stop more dirt therefor increasing engine life let more air though less retriction more power in the top end and there oil filters have an anti backflow system in there filters so your engine doesnt dry start where most damage is done to an egine also there oil filters stop more dirt than a stock oil filter or fram, i have seen them and tested them plus both the oil and air filter dont have to be replaced so they save money too, if you think they are full of shit then why are they still in business because they work i have seen it and tested them take a car to the quarter mile run with a stock air filter and then with a k&n you will cut alot of time of, also go to the drag strip EVERYONE RUNS K&N

[-nick]

Lars-

let me try to clear up a couple points:

1. you can't have too much airflow. having enormous intake ports can slow down the airflow. the velocity of the airflow is what can make you loose power.

2. properly oiling the filters is not difficult. you just oil it until you see the element change color after you've cleaned it. the oil absorbs into the element- you'd have to squirt in a lot of oil to get the filters to drip. also, it's not going to drip out when it gets hot (does a moist t-shirt drip when it gets hot if it wasn't dripping before?)

3. for dirt to get into the engine it has to pass through the filter element. when dirt sticks to the oil in a K&N it sticks to the outside of the element. it's not going to get sucked through the element, the filter just becomes less efficient over time because you've got dirt accumulating on the outside of it.

it's a moot point to argue about the efficiency of one in a 924. but as for cost, i think there's a benefit. all i do is clean the K&N at the beginning of every summer and i never have to replace it. the oil and cleaner lasts for a lot of applications. there's no doubt that it's cheaper in the long run if you have to change the paper filter a couple times.

-nick

[Lizard]

nick is right K&N are cheaper and better

[carnut280]

My father just recently purchased a used 1995 BMW M3. the previous owner had the oil analyzed with every oil change. he usually ran a stock BMW paper filter, and used a K&N only for autocrosses and races. after an autocross, he had forgotten to change back to the paper filter, and the results of the analysis of that oil change, showed a dramatic increase in the silica percentages in the oil. when he went back to the paper filter, the silica percentages decreased to what they were before when he ran the paper filter. needless to say, we continue to use the factory paper filters. just so you guy know, silica is what is used on roads in Colorado during the winter for traction. so, this proves that a K&N does let dirt through. it seems kinda odd to us, that something that lets in so much air, can block so much dirt...we beleive that K&N doesn't speak the truth.

[Mich924S]

I run a KN filter and plan on changing it every 50,000 miles. I'm not even going to bother reoiling this or that. For $50 every 50,000 miles who cares. And further, from the KN website, I recall seeing that they state their filters, when *dirty*, still outperform stock filters. I figure I'm safe changing it every 50,000 miles or so which should be about 8 years of driving for me with this vehicle. So a 1 micron particle gets in my engine. If a massive detonation of fuel and air can't obliterate it then we're all done for.

[Diesel]

From your post, I think a 'massive detonation' is in your future alright.

[numbers]

Well, there are certainly many different opinions on this subject. And you know what they say, "opinions are like assholes." This post just goes to show you that on this forum we have our fair share of both.