K&N Air Filter

Asking for professional opinions again. I have seen all the commercials for the K&N air filters. Do they really work i.e. improve performance, horsepower and get better gas mileage? Is it worth the expensive and effort to change the stock air filter for the K&N air filter?
Thanks.
Bill
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[MTI]

Please, pretty please, use the Search button first.

[Duke2.6]

In most reasonably scientific tests I've seen K&N filters marginally outperform most, but not all, cellulose filters in terms of flow restiction, but air filters are a very minor restiction to air flow unless the filter is undersized for the air flow capcity of the engine. For most applications the difference in peak power is within the range of normal test error - one to two percent.

New K&N filters supposedly pass the SAE J726 filtration test - their ability to trap particles, but their filter efficiency is highly sensitive to oil content and the amount of oil in the filter decreases with time/miles, so at some point it's filtration efficiency becomes poor, and they will pass a lot of small particles.

I find the "cleanability" of K&Ns ludicrous. Would you wash out an oil filter in solvent and reinstall it?

Bottom line IMO is that they are overhyped by aggressive marketing/advertising, not worth half the price, and their filtration quality is suspect You can buy three to six quality cellulose filters for the price of the same K&N depending on the specific filter. At 30K miles average recommended change intervals you are money ahead to use a qualilty cellulose filter and change it twice as often. A cellulose filter can clog and cause a loss of performance, but as they age they don't pass more dirt.

Duke

K&N filter success is a very nice example of a sucessfull marketing campain. They sponsor lots of HighPerformance events, are present in almost all car magazines and conduct a very high profile advertizing. BUT:
Many have reported MAFS problems as oil from the filter is sucked in and coats the MAFS
My personnal experience with K&N. A few years ago, at Moroso Race Park Fl, K&N had a display where they had installed a dynamometer for testing before/after K&N" I was there with my 1978 Vette, 383cu.in, ''reasonnably'' fed with some ''steroids''. I had a regular paper filter on the car. The rep. convinced me to go on the dynamometer for a comparative run. They had previously done several runs with other cars where HP gains were fairly impressive. However, he stongly insisted that HE runs the car, for ''security reasons''. I said..no way. I run the car. After a bit of arguement, he allowed me to run it.
First pass: 362HP @ 5,800RPM. (regular paper filter)
Second pass: 358HP @ 5850RPM, (with the K&N)
Agreed, the difference is very small and probably due to outside factors or normal variations. But my results were far from the results they were getting with the K@N driver where constant improvement of 10% to 15% were recorded with other cars. Driver tricks??? probably. most likely
Keep your hard earned money and buy a set of new spark plugs. You'll get better result with those.
JackD

[MTI]

Originally posted by Jackd
Keep your hard earned money and buy a set of new spark plugs. You'll get better result with those.
JackD

Are the platinum plugs a better buy for my Benz or should I stick to iridium . . . or copper. An, uh . . . what's better . . . Mobil 1 or regular oil?

I'd suggest gold plated plugs, (for better electrical conductivity).
Regular Mobil 1 oil is OK, as long as you mix it with 1 1/2 bottle of Never Wear (formelly known as UnderWear) additive at $36.95 an ounce. This is miraculous.
They had to change the name of the product as the first version was not very well received.
JackD

[haasman]

I personally found the Unobtanium plugs are the best in terms of perceived performance, but they are almost impossible to find.

[TexasRedNeck]

I partially agree with the other opinions that you already have received. However, unless you are modifiying a car that 1) has a great deal of performance potential, 2) has a severely restricted air box/undersized air filter, you are not going to see the performance gains they advertize. I had a 95 Impala SS and that was a classic case of where an aftermarket filter worked wonders since the stock box was baffled and restriced to keep inductioin noise to a minimum. I changed the entire intake with a cold air induction and high flow cone filter. Changing only the filter media in the stock box would have defeated the purpose. On the top end, the modified engine really benefitted from the extra air flow.

K&N claims that as the filter gets dirtier, that it actually traps more dirt because the oil has attracted other particles of dirt that in essence become filter media. You decide. As for the MAFS problems, they can usually be tracked back to users to over lubricate the filter after cleaning.

I personally use them in all my vehicles, from the SS to the HD Crew Cab, to the E320, and the Triumph Daytona, partially for the performance/economy gains, but probably because I like piddling.

To sum it up, unless you have a car with some serious up side performance potential, or just like to piddle, you could spend the money else where. If you do use one, just make sure you follow the cleaning and oiling directions very carefully.

[MTI]

It's deja vu all over again . . . btw, what's the best way to drain that old dino oil before I convert to Mobil 1 . . . topside or drain plug . . . somebody stop me!

[haasman]

Don't forget: While waiting for the oil to drain.... being sucked out .... er .... whatever .... whats the best wax to use?

[JSlabotsky]

Since we're wasting time anyway....

I particularly enjoyed the one about gold-plated spark plugs.

The hype about platinum plugs is similar to the hype about "oxygen-free copper" for speaker wire. I read a pretty credible university study that showed no measurable or perceptible difference between expensive wires and plain-ol' lamp cord.

Can anybody recommend a good synthetic blinker fluid?

Well guys, again thanks for your input. I now know that the K&N filter has a great advertising campaign, but in the long run the gain is not worth the expense or effort to switch. I also really enjoy the chatter back and forth. Since I am new to this site I did not realize that there was a search engine for my questions. Will use it next time MTI, thanks for pointing it out.

[RickM]

The list I've come up with from years of using, asking, reading & debating.

-NGK Copper plugs (or Bosch copper)
-Mobil1
-Mahle, Mann or Wix oil filter
-Meguires #26 pure yellow carnuba...Final inspection between waxings
-Standard OE air filter. Over on the 911 board a similar dyno run was run and a decrease in HP was realised with the K&N.

PS: Please dont ask about the ERAM electric supercharger.

[MTI]

I have to admit that I have a pre-oiled K&N cone filter on my 190E, but only because I switched over to a custom air intake. If I still had the stock air box, I would have stuck with the disposable filter cartridges. Since my car is fairly high milage, I'm also sticking with the dino oil and changing every 3K, although I do admit to synth oil envy.

[RickM]

Why can you not use synthetic oil on a high mileage car? I've done it with no ill effects.

If your car has leaks I could understand but if it doesn't going to synthetic will not create them.