Hi Guys. I was planning to buy the washable Highflow K&N oiled air filter because it is highflow and suppost to be better; however after reading some reviews about it, I could not believe what I found. I will post the link of the testing video I watched below.
K&N oiled filter can improved your car acceleration 0.1 sec vs paper air filter. However it is the worst air filter in filtering small particules (less than 5 micron and large particules about 5 microns). So lots of dust (sand) goes into the engine ( engine will wear sooner).
In my opinion this will apply to all those filters similar to K&N (oiled or not oiled and washable) unless some one testing demostrate how well a particular filter brand is filtering.( unfortunately we can not trust what the manufacturer label say most of the time).
in summary, paper air filter Wix and Purolator One ($20+) were the best followed for EP auto?($8). Fram guard 2x and K&N were the worst.
Any comments appreciated. Video link below.

https://youtu.be/sJ3L-E-ufYo

 

You should be good with the OEM filter. Offers probably the best protection filtering. You won't gain anything with the k&N other than some noise. AFAIK the stock filter on the dyno performed the best.

 

JM2C but back in the day, a lot of manufacturers fitted filters that were physically restrictive. K&N came in and maximized flow volume and filter area with a bonus of reusable filters.

New manufacturing techniques wised up and used filters that in many cases, breath well and are not a notable source of restriction.

Point, in many cases there is less to gain than the old days and now you have this super sensitive MAF sensor that needs to stay oil free to prevent accumulation and degradation of engine performance.

In my opinion, that last point is the final straw and gets a no vote from me.

 

The testing results with less restrictive filter like K&N gave 0.1 second faster than more restrictive filters; however very poor filtering so more dirt goes in to the engine (it is like running without an air filter). Paper filters are the best but not all paper filters are filtering. So buy the brand that do the best . Stay away from washables filters and high flow filters until some one do the filtration testing in youtube not just the dino or acceleration test. Bottom line, you want clean air to the engine so it can last and run forever.👍
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The statement about poor filtering is not true. I've been using K&N filters for over 10 years, on two of my cars they are installed on, filters have been serviced (cleaned and re-oiled) at least once. My 2006 Camry SE (3.3L V6) has 155K miles on it. Filter has been cleaned once and is due for a second cleaning. My 2013 Toyota Sienna has almost 140K on it, filter was cleaned once and is coming up for a second cleaning. My 2010 IS350 has been using it for 10K. Previous to that I had a 2018 Civic Si (sold) that used it for 17K. If it was true that it had poor filtering, it would have shown up in oil analysis I do once every other oil change that I sent to Blackstone. My last oil analysis had 7K of hard driving, and oil analysis showed no abnormal wear, and oil was still in good condition and could have gone another 3K before changing

I think statements like it has poor filtering should be backed up by facts. K&N posts results from filtering tests on their site, and the results posted show they filter pretty much as well as stock filters. They also offer a million mile warranty, which no OEM does. I don't think they would offer such a warranty if their filters did not more than adequately protect engines they are installed in

You don't buy K&N filters because you are trying to achieve more HP. You buy them because they last pretty much the life of your car (K&N says they can be cleaned up to 4 times at 50K each), so you save money, and you don't have to change your air filter as often

 

I've used the AEM dryflow a few times in the past. My city commute to work involves some patchy road work. Big rigs are hauling dirt from an ongoing retention pond being made. The road is semi dusty at times. The AEM lets in more dirt than I would like. I can see the buildup inside my intake pipe. It makes its way all the way to the throttle body. On a stock filter if you've ever changed it. You will see a build up of dirt that stays trapped in the lower airbox baffles. Now with the AEM dryflow you don't see that build up. Imagine those particles hitting the MAF thermistor daily. I would assume it would damage them after a few thousand miles.

 

I can't speak for your individual driving situation, it's possible in your driving conditions OEM is better, I can only use my experience in which my cars have been trouble free going 100k plus on K&N filters. My intake has been pretty clean, although I have not taken my throttle body out. But oil analysis would tell you if contaminants are getting in, which so far it's not the case. My next oil change is coming up and I plan to send a sample to Blackstone for analysis, I will post it on this forum. One other thing, although AEM are made by K&N, it's possible that the oiled K&N filters trap finer dust and particles the dry type filters don't

 

Hey guys I respect your opinion if you like to use K&N oil washable filters. I like the idea about saving money by washing the filter (like my central A/C). However, My wife has one K&N in her Highlander which I am going to get rid off ( I noticed a fine dust film in the air intake after the filter). This is not the first time I am hearing about poor filtration of this filter. I like an unbiass testing (not from the manufacturer); so watch the youtube video about air filter testing and find out what is good for you based on the facts👍

You Tube

Moreover, if you see someone doing testing air filters on youtube or anywhere, please share with us.

 

Attached is a Blackstone Labs oil analysis for a 2018 Honda Civic Si (turbo charged) that I performed last year. I drove the car hard over 5,600 miles, taking it on 3 trips between Northern and Southern California (350 miles each way), doing sustained driving over 80 MPH through all kinds of conditions (farmland, mountain passes, gusty winds etc). In many cases I was frequently hitting boost between 10psi and 23psi. This car had a K&N filter from 30 miles on the odometer all the way to past 17K when I sold it. No unusual contaminants or engine wear. If the K&N filter had not been doing it's job it would have shown up in the oil analysis and caused unusual or excessive wear in the engine. I don't think K&N would give a million mile warranty if it could not properly protect an engine

 

I've subbed to him and have watched quite a few of his videos. They're top notch, very informative. He'll go and redo a test if someone in the comments points out a flaw in his testing. Definitely unbiased as well.

Paper filters have came a long way from the old days, I think even lately some have tested where new ones are getting near K&N's flow. The main issue with oiled filters like K&N is the oil that can get on your MAF, and they are super finnicky about getting gunked up with oil. Problem with cleaning them is typically people over-oil them and that's what usually causes MAF issues. K&N and similar filters using get about a 97-98% filtration rating, while your common paper filter gets 99%. Those filters are still letting in 2-3x more particulates than the paper filter does, and it's really dependent on your climate as well. I used to be in the K&N camp, even tried out some of the dry filters too, but ended up just going back to paper filters.

 

I totally agree with you that there are people that over-oil them, and if you do over oil them the excess oil will get on the MAF, but really, if you follow directions, they are easy to oil. I've cleaned them and re-oiled them on several of my cars and never had issues. Basically 1 thin layer of oil on each side of the filter. If there is any dripping oil, you have to re-wash the filter and start all over again