I see a lot of you are down on K&N air filters.
What are your reasons?
What are your actual experiences using them?
Been told that Honda and other manufacturers wiWill not honor their warranty on any engine using a KNM air filter. Personally use one on my work truck . Don't want to risk a $20,000 motor over what is a small savings as little as we drive our motorhome
Repeated failure of IAC on a Ford V10 in our first motorhome. After researching the problem, got rid of the K&N (which had been installed as part of a Banks performance upgrade) and no more issues.
The reason they let ore air in is that they do a worse job of filtering.
I put one on an old diesel truck of mine and did an oil analysis both before I put it on and then after 6000 miles with it. Same interval and same roads and conditions and more silica in the oil with the k and N and pulled it and repeated and back down.
FWIW...My mechanic installed a K&N air filter on my 01 F250 at approx 90,000 miles. Now have 390,000 miles and 7.3 runs great and uses no oil between changes every 5,000 miles since new. So no complaints but will stick with Fleetguard for my M11. Oil gets changed way more often in my truck than in the coach.
As spike45 points out in the posts below (scroll down a bit), Fleetguard considers their air filter failed if they only filtered 99.6% of the dust. K&N advertises that their filters only filter out between 96-99% of dust.
Air Filter - Engine (http://www.foreforums.com/index.php?topic=10221.25)
Also, if you look at the diagram on page 24 of this Donaldson literature, it shows a rather large difference in dust ingested over 100 hours of engine operation in a medium dust application between filters rated at 99% and 99.9% efficiency.
http://india.donaldson.com/en/engine/support/datalibrary/061238.pdf
K&N is known to allow enough dirt thru to allow massive erosion to turbo blades on engines operated in dusty environments. Plus the whole "flows more air" is kind of a joke considering there is nearly zero restriction with our large paper filters that do an amazing job of filtering dirt and probably only need to be changed once or twice over the life of the average RV. (We probably change them more, but if going by restriction, 100,000 miles probably isnt out of the question)
A friend from the bus RV world has a GM4104, we converted to the 8V-71 & Allison Vee drive auto, also installed a proper paper air filter system, the next time he came thru for servicing, he needed starter fluid to start it, soon found he replaced the paper filter with the K&N wonder, asked why, he said, because the paper stopped up way too quick, the KN never stopped up as he ran the Baha beaches etc. So he needed cylinder kits, blower, head rework, even put new bottom end bearings in. Back to great running, starting etc including a new paper filter. I bet he will change back to the K&N, being a retired Bright Bulb, mechanical things seem to elude him, but he has plenty green stuff. Why I say "Do what makes you happy"
I don't think it's appropriate to make such comments, putting down an entire group of people. You might want to read the "Clarkson" topic The Jeremy Clarkson Effect (http://www.foreforums.com/index.php?topic=25578.0) .
Sorry for the POOR choice of words for my old buddy, if you knew him you would understand. ;D
Rethinking this subject, I think a few would love using the K&N, with all the extra power etc.
I have a K&N and love it. It gives my 6V92 Detroit extra HP.
The key thing most don't realize is any air filter actually gets better after it accumulates a layer of dust and particles. So, -
don't change your air filter too often, or over wash your K&N filter. I am confident my K&N is working fine, and I clean it only when my K&N filter minder is at 75%.
My Detroit uses very little oil, and runs like a sewing machine.
I added greatly to my retirement income from my hobby biz of building off road four stroke large displacement single cylinder dirt bike engines from owners running K&N's.
They make a pre charger ultra fine woven cover to add the ultra fine filtering that the cotton gauze does not do.
Yes dirty they filter much better.
Used to pull them off buddies bikes and white cloth the intake tract many times.
Always fine dust.
The synthetic foam seems to have tiny enough openings to fine filter everything out of the air.
Woven cotton does not as far as my old info goes.
Especially in a high suction use. IMO.
Same with woven stainless steel oil filters in the same motors.
Smallest opening in them was 35 microns and anything smaller went right through
Our paper filter gets dirty pretty fast as it's doing it's job well. $60+ is cheap insurance against engine damage. A Detroit will always run smooth as glass, have plenty of power and not use much oil unless it's really tired. Bore wear will be the first casualty with harder and harder winter starts. This goes for 4 cycles as well. We had to get a hotel up high above the main road with a Mercedes that had bore wear. Mornings meant second gear downhill for a half km before it would start. We had to come back to the car every two hours in the city and run the engine for about 10 minutes to keep it warm.
I am nominated to play Scrooge or Marley in our town play every Christmas (for a reason) so know that you could buy several truckloads of paper filters against the $20,000 plus an overhaul costs. Aftermarket filters mean it's just a matter of time...
Pierce