K&N's statement on their filters' ineffectiveness at filtering

[exdeath]

But K&N has a long list of users with nothing but positive things to say...

Are these the same people who brag that their K&N added 50 RWHP to their bone stock Corvette but have never had a dyno sheet?

 

[Throckmorton]

I would expect that there would be wide reports by auto enthusiasts of dirty intakes and dirty air ducts. The more meticulous ones that take oil samples and send them to Blackstone would also have noticed heavier build up in the engine oil of certain elements that indicate greater engine wear.

More dirt DOES show up in the oil analysis. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=490965.

http://www.thedieselpageforums.com/tdpforum/archive/index.php/t-12884.html

From the diesel forum:
A member over at the Tundrasolutions.com site ran an oil analysis on his K&N equipped Tundra, then switched to the OEM air filter element, ran same mileage and did another oil analysis. The paper elemented oil analysis reflected a significant drop in intake dirt levels along with a corresponding reduction in wear metals. He is continuing his personal test program having installed an Amsoil air filter. He will publish the results for the Amsoil, K&N and stock oil analysis results.
Also there is another site http://www.avlube.com/ which has some relevant data.
George Morrison, STLE CLS

What are you arguing? It's just a fact, proven by scientific testing, that K&N filters let in much more dirt, 45x according to ISO testing.

Are you arguing that more dirt is not bad? Then why run a filter at all?

 

[Throckmorton]

You can have a good filter that flows better, but such filters are BIG. The 12" filter I have in my car barely fits in the wheel well and looks like something off a diesel truck.

It's all about surface area, or more specifically the flux or flow per surface area.

Denser media that can only flow so much per inch requires more media to flow the same mass of air while retaining high filtration.

I'd like to see someone building aftermarket airboxes that hold dual filters, maybe set up at an angle to fit them into the same space.

 

[Doppel]

You newbs r gone hate but k&n in my civic SI let's me spank all kinds of cars at the lights. Just last night I took a guy in a Toyota yaris, almost.

I also use monster cables to my bose speakers and a tornado fuel saver.

 

[Raizinman]

People who have spent hundreds of dollars on a K&N CAI (Cold Air Intake) or even the guy who spent $30 or $40 for a drop in filter obviously are going to defend their snake oil purchase. Otherwise, they look pretty foolish. The test results I posted earlier apply to both the CAI and the K&N drop in filter. Just because an air filter is expensive does not mean it is better.

Getting independent people who claim their car now runs better means absolutely nothing. Due to the design of the K&N filter most people will hear more engine noise which gives the psychological effect of more power. An air filter cannot possibly give you any extra HP, unless you are comparing a VERY VERY VERY dirty air filter to a new air filter.

If you were to run a VERY VERY VERY dirty air filter at full throttle, eventually you would set a CEL, as your oxygen sensor would detect a rich condition due to the lack of air. This does not happen very often and the air filter must be almost fully blocked to set this code.

Like many, I succumbed to the advertising of K&N and purchased one of their filters, believing and hoping that it would give me a few more HP and MPG. It didn’t, which is when I started researching K&N and found their claims to be ridiculous.

 

[Apex]

Simply put, there are only a few ways to increase airflow through a filter. Reduce the filtering ability or enlarge the filter. K&N is a drop in, so it isn't magically larger, so what's that leave? (Yes, i'm oversimplifying it, so get off my back!)

Actually, there's 1 more, and this is actually a pretty important one: Greater open area in the mesh element.

In other words, let's say you have two 5" x 5" flat filters. One is made of screen door material. The other is a sheet of steel with a single 1/4" hole punched in it. The screen door filter will flow better AND filter better, despite being the same size.

This is, of course, a gross oversimplification. However, it does speak to the difference that different media element open area can make.

This is why foam filters, cotton filters, and paper filters will often filter differently, even given the same size and flow.

 

[Gillbot]

Actually, there's 1 more, and this is actually a pretty important one: Greater open area in the mesh element.

In other words, let's say you have two 5" x 5" flat filters. One is made of screen door material. The other is a sheet of steel with a single 1/4" hole punched in it. The screen door filter will flow better AND filter better, despite being the same size.

This is, of course, a gross oversimplification. However, it does speak to the difference that different media element open area can make.

This is why foam filters, cotton filters, and paper filters will often filter differently, even given the same size and flow.

Yeah, there's also the argument of more pleats and etc as mentioned before, but I thought I also covered it already by saying:

(Yes, i'm oversimplifying it, so get off my back!)

 

[Ronstang]

Except his car is probably down on power due to worn out valve seats and rings from the K&N allowing ~10-15% more dirt I mean airflow into the engine.

Do you actually know anything about the inside of an engine? My Shelby has 4 Weber 48IDA carburetors on it. A venturi exclusively for each cylinder. The problem is there are no good air filters for this carb setup. If there were they wouldn't fit anyway as the air horns of the carbs stick right up into the hood scoop. You can see them standing in front of the car.

When I had about 15K miles on the engine I bent a few exhaust valves when I hit a patch of wet pavement under WOT acceleration and hit about 9K on the tach. I tore the engine down to fix the heads. I was curious what 15K miles with no air filters on a healthy breathing engine (that turns over 4K rpm on the highway due to gearing) would do to the inside. It didn't really look any different than any other engine I have torn down.

That same engine had 50K miles on it when I parked the car to await it's restoration. It was not down on any power. That car has always been rather fun with that engine setup in it. It has not had any air filter at all for all 50K miles and it was driven on regular roads. The only special care I took was 1000 mile oil changes and if I could see a cloud of dust on the road I would simply turn off the engine and coast through the cloud and then start it up again.

I am not suggesting you drive around with no air filter. All I am saying is the average dirt floating around in the air is not going to kill an engine like you think it will. Yeah, if you live near a beach and the sand is blowing around all the time then you might have a little more of a problem. Most dirt light enough to be in the air is going to either go right out the tailpipe or into the oil. Change the oil regularly with a new filter each time an I wouldn't worry about it.

The engine in my Shelby is original which means due to rarity it is worth more by itself than a lot of cars on the road. Yet I drove it 50K miles with no air filter. I didn't even worry about it and the tear down proved I didn't have much to worry about.

 

[Apex]

Yeah, there's also the argument of more pleats and etc as mentioned before, but I thought I also covered it already by saying:

Haha, fair enough, fair enough.

 

[RPD]

Anyone know how legit this one that supposedly GM makes, that looks a lot like other K&N type of intakes? http://www.gmpartsgiant.com/oem/2007-chevrolet-avalanche-performance-air-intake-3043.html

 

[Throckmorton]

Anyone know how legit this one that supposedly GM makes, that looks a lot like other K&N type of intakes? http://www.gmpartsgiant.com/oem/2007-chevrolet-avalanche-performance-air-intake-3043.html

There's nothing wrong with the K&N intakes, just the filters. That GM filter is non oiled. Looks like a foam filter or maybe it's just red paper

 

[RPD]

There's nothing wrong with the K&N intakes, just the filters. That GM filter is non oiled. Looks like a foam filter or maybe it's just red paper

Well right, the filter pictured looks a lot like K&N types. How well does the Volant Powercore filter? http://www.carid.com/universal-air-filters/volant-air-filter-347270.html

 

[Meghan54]

I have to shake my head at the defenders of K&N and their denial of K&N filters allowing more dirt to pass the filter vs. an OEM type paper filter. While it's an undeniable fact, there are still those that don't believe....c'est la vie.



Of course, none of the defenders ever bring up the fact that K&N themselves recommends their prefilter be added if you are going to drive in dusty conditions/areas, such as the prefilters seen on the aforementioned SCORE race vehicles. Ever wonder why the prefilters even exist? Because the K&N filter allows too much dirt to pass......of course, this is only if you drive where there's dust in the air..... ROFL!!!!!!!!!!!!!


K&N calls them the PreCharger and DryCharger:


http://www.knfilters.com/search/wrap.aspx




As K&N states on its page for the prefilters:

The PreCharger will stop small dirt particles.....
The DryCharger will also stop small dirt particles....

So, if it takes the use of the prefilters to stop small dirt particles from passing through the air filter, what good is the K&N filter in the first place?

 

[Gillbot]

So, if it takes the use of the prefilters to stop small dirt particles from passing through the air filter, what good is the K&N filter in the first place?

It makes your car more powerful? :whiste::biggrin::awe)

 

[HybridSquirrel]

I can confirm, that after throwing a paper filter into my car last night I instantly lost 50whp....back to the k&n

Here is the dyno chart

Pretty cut and dry, i'm sticking to my k&n

 

[angry hampster]

I can confirm, that after throwing a paper filter into my car last night I instantly lost 50whp....back to the k&n

Here is the dyno chart

Pretty cut and dry, i'm sticking to my k&n

I can vouch for this. My K&N filter added about 30-40 horsepower.

 

[Raizinman]

Each K&N decal you put on your car adds 10 HP.

 

[Pulsar]

I would expect that there would be wide reports by auto enthusiasts of dirty intakes and dirty air ducts. The more meticulous ones that take oil samples and send them to Blackstone would also have noticed heavier build up in the engine oil of certain elements that indicate greater engine wear.

Let me get this straight.

The data is clear - K&N filters allow more dirt to flow through.

Yet you're continuing to try to discover individual anecdotal evidence to support that they work just fine?

Are you going to start arguing with automakers next that increasing the dirt in the engine really doesn't do anything to it?

Where's a facepalm logo when we need it.

 

[Pulsar]

I've noticed most of these types of threads get started due to scientific tests of the filter, rather than actual negative personal experiences.

Oh my god.

 

[Throckmorton]

Well right, the filter pictured looks a lot like K&N types. How well does the Volant Powercore filter? http://www.carid.com/universal-air-filters/volant-air-filter-347270.html

We'll never know until someone tests it

 

[thomsbrain]

The K&N FIPK intake does make power on the S2000, as has been demonstrated by plenty of owner dyno tests (though only about half the claimed power bump). However, it's very likely that this has to do with intake resonance and nothing to do with "flow resistance." It has a solid pipe that is about a foot longer than the stock soft tubing. The stock filter is already the size of my head and I doubt the K&N filter makes much difference.

 

[Raizinman]

The K&N FIPK intake does make power on the S2000, as has been demonstrated by plenty of owner dyno tests (though only about half the claimed power bump). However, it's very likely that this has to do with intake resonance and nothing to do with "flow resistance." It has a solid pipe that is about a foot longer than the stock soft tubing. The stock filter is already the size of my head and I doubt the K&N filter makes much difference.

Dude, its not possible for a K&N air filter to 'make power'. It's an air filter plain and simple. Not a supercharger, not a turbocharger, just an air filter. Unless you are comparing it to a very very very clogged air filter, the stock OEM filter will pass the same necessary amount of air required by the engine, no different than a K&N. Dyno tests showing a 1 or 2% increase can be attributed to so many different things. Even testing an hour later with the same air filter can change the HP scores due to humidity or temperature. K&N even acknowledges this on their website.

If your engine needs X amount of air, and both the OEM filter and the K&N filter can supply X, why would the K&N create more HP?

 

[JCH13]

Dude, its not possible for a K&N air filter to 'make power'. It's an air filter plain and simple. Not a supercharger, not a turbocharger, just an air filter. Unless you are comparing it to a very very very clogged air filter, the stock OEM filter will pass the same necessary amount of air required by the engine, no different than a K&N. Dyno tests showing a 1 or 2% increase can be attributed to so many different things. Even testing an hour later with the same air filter can change the HP scores due to humidity or temperature. K&N even acknowledges this on their website.

If your engine needs X amount of air, and both the OEM filter and the K&N filter can supply X, why would the K&N create more HP?

Did you read his post?

The K&N FIPK intake does make power on the S2000, as has been demonstrated by plenty of owner dyno tests (though only about half the claimed power bump). However, it's very likely that this has to do with intake resonance and nothing to do with "flow resistance." It has a solid pipe that is about a foot longer than the stock soft tubing. The stock filter is already the size of my head and I doubt the K&N filter makes much difference.

 

[Throckmorton]

Dude, its not possible for a K&N air filter to 'make power'. It's an air filter plain and simple. Not a supercharger, not a turbocharger, just an air filter. Unless you are comparing it to a very very very clogged air filter, the stock OEM filter will pass the same necessary amount of air required by the engine, no different than a K&N. Dyno tests showing a 1 or 2% increase can be attributed to so many different things. Even testing an hour later with the same air filter can change the HP scores due to humidity or temperature. K&N even acknowledges this on their website.

If your engine needs X amount of air, and both the OEM filter and the K&N filter can supply X, why would the K&N create more HP?

Same reason a wider intake pipe or a fatter exhaust pipes increase horsepower, by reducing airflow resistance. That's not the issue here. I you run with no filter at all you will increase your horsepower slightly just due to lower drag on the intake stroke.

 

[thomsbrain]

Same reason a wider intake pipe or a fatter exhaust pipes increase horsepower, by reducing airflow resistance. That's not the issue here. I you run with no filter at all you will increase your horsepower slightly just due to lower drag on the intake stroke.

As I posted, it's not an air "resistance" issue, it's a resonance issue.

Engines are pulsing instruments and with various length and width pipes on the intake and exhaust and various RPMs, you will approach resonant nodes or harmonics that reduce restriction for a while, similar to playing a flute and getting the air you're breathing to properly match the resonance of the flute. When you hit it, BAM, you've got smooth air flow and music. Filters have little or no effect on resonance.

Exhaust test-pipes that "make power" generally do so for the same reason, because they improve the resonance of the exhaust line. That's why "high-flow" cats rarely make power. They only change blockage, not resonance issues.

You can find dyno videos on youtube of people building experiment intakes that are like six feet of solid tubing reaching into the sky. The longer tube gets the resonance down really low and lets the breathing approach more acoustically tuned nodes than a short tube, similar to a pipe organ. They make power that way, but of course you can't actually drive anywhere with one of those things.

Intake and exhaust breathing has more to do with acoustical science than it does with reducing "blockage".