People's opinions on K&N

[ChicagoTransAm]

It may be argued that they simply want to sell their filters

Which would be illegal unless they provided the filters at no cost to the consumer. That is, automotive manufactorers cannot require any part or fluid to be purchased through themselves to maintain warranty.

It just needs to meet or exceed OEM specs.

http://www.mlmlaw.com/library/guides/ftc/warranties/undermag.htm


BTW~Cool site ;-)

 

[MRC01]

quote:

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Originally posted by jsharp:
I've been using K&N filters for 20+ years and while they may not filter as well as paper, they seem to filter well enough. I have one vehicle over 200K miles with no problems and the recent oil analysis on another showed no problems...

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I'm using a K&N on my motorbike and on a high performance car, both show below average Si on their UOA. No doubt the K&N flows well, and it seems to me they filter well enough too.

 

[bernhardschau]

Just my 2c worth wich I have already posted to another message on K&N:

I've never done UOA to determine Si in my oil. I've used K&N filters in several non-performance cars. I clean them about every 30K/Km and every 10K/Km I apply a little more oil. I've never had any engine problems or found any dirt residue on the clean side of the filter. I like the filters not because the air flow issue but because they are more economical and environmentally friendly in the long run. I did find the air filter test found on Bob's home page to be very interesting. It did show that a little more dirt bypassed the K&N, however, the paper filters tested also had considerable bypass dirt. I've got the K&N's in my cars now and will not be throwing them out. When it's time for a new car, I might revisit the issue again. [Smile]

 

[Patman]

quote:

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It's more to satsify my curiosity than anything else. I still think the K&N filters well enough if properly maintained...

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Actually, it filters better if you just leave it alone. Those people who clean them once or twice a year aren't doing themselves any favors, as a freshly cleaned K&N lets in a lot more dirt than a dirty one will.

 

[TooSlick]

Oil analysis only tests for dissolved ions and particles small than about 5 microns/um. What you really want to look at is the rate of Fe/Cr/Al wear from the cylinder walls, piston rings and pistons. I'd also look at bearing wear, specifically from the softer lead alloys.

Tooslick

 

[jsharp]

quote:

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Originally posted by Patman:

quote:

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It's more to satsify my curiosity than anything else. I still think the K&N filters well enough if properly maintained...

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Actually, it filters better if you just leave it alone. Those people who clean them once or twice a year aren't doing themselves any favors, as a freshly cleaned K&N lets in a lot more dirt than a dirty one will.

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Agreed. I sould have specified what "properly maintained" meant.

I don't mess with them until they get pretty dirty, typically every 1-2 years, and I know how not to overoil but to get enough on the filter that it'll do it's job...

[ September 28, 2003, 02:58 PM: Message edited by: jsharp ]

 

[Jason8691]

After reading all of these posts I went and checked my filter housing. I have a 03 S10 with the 4.3L, I drilled holes in the bottom of the housing and installed a K&N. Its been in there about 3K miles and there's dirt on the screen in front of the MAF. So out the K&N came! Now all I have to do is see if Auto Zone will give me my money back.

 

[jsharp]

quote:

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Originally posted by MRC01:

quote:

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Originally posted by jsharp:
I've been using K&N filters for 20+ years and while they may not filter as well as paper, they seem to filter well enough. I have one vehicle over 200K miles with no problems and the recent oil analysis on another showed no problems...

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I'm using a K&N on my motorbike and on a high performance car, both show below average Si on their UOA. No doubt the K&N flows well, and it seems to me they filter well enough too.

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The UOA I did on my truck with a K&N showed higher than average Si readings, but nothing to be alarmed about. It got me to wondering though, so I changed to a paper element 1/2 way through this interval to see if the next UOA looks any different.

It's more to satsify my curiosity than anything else. I still think the K&N filters well enough if properly maintained...

[ September 28, 2003, 12:34 PM: Message edited by: jsharp ]

 

[shortyb]

quote:

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Originally posted by TooSlick:
Oil analysis only tests for dissolved ions and particles small than about 5 microns/um. What you really want to look at is the rate of Fe/Cr/Al wear from the cylinder walls, piston rings and pistons. I'd also look at bearing wear, specifically from the softer lead alloys.

Tooslick

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Good point. While my UOAs don't have elevated Fe (warmer weather?), my Al, Cr, and Pb #s were up slightly. Both cars using the K&Ns. Now while they weren't all that bad, I would like to see if I can get them better. In my case, this means giving a fiberous filter a try for a few intervals to see what happens.

 

[JWRENCH]

Maybe a tid bit of grit hitting the pistons could be a good thing and clean some of the carbon build up off.

I have no doubt that K&N filters let a small amount of dust go by cause I've seen it and can post pics of it if need be.

That said, I run them on both of my vehicles because I like the boost in power and mileage. Besides, that's why I pay nearly ten bucks for a premium oil filter.

 

[Richin Chicago]

quote:

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Originally posted by kondor:
The Cummins website Dodge link has specific reference to high air flow filters, namely K&N filters in the FAQ. Cummins states that their experience is that such filters like the K&N filter allow enough stuff through to score pistons.

One assumes, since they mention specifically the brand, that they have an evidentiary basis for such a claim.

Just a caution for the cautious. No remarks about airflow, simply piston scoring.

Although Cummins doesn't warrant the Dodge Cummins, they say in the FAQ that DC and Cummins do not allow such filters.

It may be argued that they simply want to sell their filters, but a specific claim was made pertaining to a named manufacturer and in today's tort climate one assumes they are prepared to go to court.

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Here is the site. It's enough along with higher SI numbers to keep me away.
http://www.cummins.com/na/pages/en/....cfm?uuid=00060D72-0093-1B8D-BCF080C4A8F00000

 

[ShootingStar]

I'm no fan of K& N air filters but do understand that Cummins and Dodge have a vested interest in convincing you to use only OEM factory parts.

 

[road_rascal]

We have 2 microturbines at my work for generating electricity. One is a 30kw and the other is a 60kw. They both spin up to 95,000 rmps on air bearings (no oil). And they both came shipped with huge K&N air filters. I generally have to clean and re-oil them about every two months. So if Capstone microturbines are shipped with K&N filters, I guess they're OK. Although I personally use OEM filters in my cars and Uni filters in my motorcycles. Just my $0.02

 

[BadBatsuMaru]

Anthony has a very well done test, and it makes perfect sense that the K&N filter would trap less dirt.

The only problem I see is that in every test, the amount of dirt on the second filter is directly proportional to the flow-rate of the first filter. Higher flow = more dirt. The obvious conclusion is that the higher flow filters trap less dirt, but there could be other reasons. Higher flow quite simply means that there is more air passing through the second filter, so of course it's going to get more dirt on it! The only way for the second filter to remain as clean with a high-flow primary filter would be if the filter's efficiency increased proportionally with airflow, which would be quite a feat. There's also another possibility. The engine pulls air through the intake. The air will take the path of least resistance. There may be small areas beyond the second filter where a little air is able to enter. When you stick a restrictive paper filter in the box, that will therefore cause more air to be drawn through any leaks beyond the second filter, causing the second filter to trap less dirt.

Of course, all this devil's advocate talk probably isn't necessary. If there are UOA's showing increased silicon with nothing changed except the filter, then there you have your answer.

One other thing you have to keep in mind, though, is that just about anything you do to get more power out of an engine puts more stress on the engine. You've got half the people on here who no doubt think it would be ridiculous to put a K&N filter on your car if there is a chance of it actually being worse for your engine than a Fram. That's understandable. At the same time, you have to understand that a cold air intake with a K&N filter sounds good, looks good, and gives you a tiny bit of power. Nobody's advocating a 100-shot NOS system here. You can, however, easily argue that a high-flow air filter gives a boost in performance and the extra wear is almost completely inconsequential over the lifetime of your engine.

 

[AnthonyS]

quote:

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Originally posted by BadBatsuMaru:
Anthony has a very well done test, and it makes perfect sense that the K&N filter would trap less dirt.

The only problem I see is that in every test, the amount of dirt on the second filter is directly proportional to the flow-rate of the first filter. Higher flow = more dirt. The obvious conclusion is that the higher flow filters trap less dirt, but there could be other reasons. Higher flow quite simply means that there is more air passing through the second filter, so of course it's going to get more dirt on it! The only way for the second filter to remain as clean with a high-flow primary filter would be if the filter's efficiency increased proportionally with airflow, which would be quite a feat. There's also another possibility. The engine pulls air through the intake. The air will take the path of least resistance. There may be small areas beyond the second filter where a little air is able to enter. When you stick a restrictive paper filter in the box, that will therefore cause more air to be drawn through any leaks beyond the second filter, causing the second filter to trap less dirt.

Of course, all this devil's advocate talk probably isn't necessary. If there are UOA's showing increased silicon with nothing changed except the filter, then there you have your answer.

One other thing you have to keep in mind, though, is that just about anything you do to get more power out of an engine puts more stress on the engine. You've got half the people on here who no doubt think it would be ridiculous to put a K&N filter on your car if there is a chance of it actually being worse for your engine than a Fram. That's understandable. At the same time, you have to understand that a cold air intake with a K&N filter sounds good, looks good, and gives you a tiny bit of power. Nobody's advocating a 100-shot NOS system here. You can, however, easily argue that a high-flow air filter gives a boost in performance and the extra wear is almost completely inconsequential over the lifetime of your engine.

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Most would agree that an engine needs a fixed volume of air at a given rpm in order to fill the cylinders. You can actually calculate this air demand in cfm. This amount isn't going to vary all that much depending on which filter is in the intake tract based on the limited testing I did. The absolute pressure differences realized were in reality very small. I agree with you though, because it only makes sense that filtration ability and flow are inversely proportional.

The cold air kits that show power increases are most likely due to a large reduction in pressure losses associated with the factory airbox and intake plumbing and not the filter used itself. I bet you can put a properly sized paper cone filter on a cold air kit and realize the same exact power gain and have better filtration.

 

[BadBatsuMaru]

quote:

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Originally posted by AnthonyS:
...
The cold air kits that show power increases are most likely due to a large reduction in pressure losses associated with the factory airbox and intake plumbing and not the filter used itself. I bet you can put a properly sized paper cone filter on a cold air kit and realize the same exact power gain and have better filtration. [/QB]

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That's probably true. I'll bet a paper cone on a short-ram CAI sounds just as good, gives better filtration, and gives 99% of the performance boost of a K&N filter that you have to wash & oil.

It seems hard to find a good mandrel-bent CAI that doesn't make you buy the K&N filter, too, though. I also can't seem to find a reputable-looking place selling paper cones that would fit on your standard AEM intake.

 

[jason07-1zzfe]

Get a Donaldson truck filter. They're cylindrical, instead of conical. But they are huge. Guaranteed to out filter a K&N and I would bet out flow. Bigger is better.

 

[Jason8691]

I recently took the K&N out of my truck and replaced it with a paper filter becuase it was letting dirt get by. My gas mileage hasnt dropped and the performance hasnt changed. The more I read about these filters combined with the experiences Ive had, I believe they may fall into the "snake oil" category. Is one or two more HP really worth dirt in your engine? Is it worth waiting until they get dirty before they start filtering correctly? I dont think so.

 

[boxcartommie22]

i like fleetguard filters the best

 

[Volkster]

My direct experience with K&N filters in automotive applications is somewhat limited. I installed one in an old Volvo I used to have, but I didn't notice any difference so I sold it to a friend. I do, however, have a hobby related experience to share. One of my passions is nitro powered r/c cars. K&N makes small breather filters which are easily adaptable as a main air filters on small nitro burning engines. They DO provide a noticable performance increase, but at great risk. In a .15 nitro engine, the ingestion of a partical the size of a grain of sand is equivelent to dropping a small screw or bolt in the intake manifold of a full size car engine. I've seen several nitro engines meet such a fate that can be directly attributed to a K&N air filter. Many r/c hobbists still use them though. For on-road racing the risk is minimal, since there is less dust kicked up on the track. But using a K&N in an off-road vehicle is just asking for trouble.