Thoughts on K N air filter


I traded a disk for a 1999 F-250 that has an aftermarket K & N air filter. Are they any good I have heard mixed results some saing they are junk for dusty conditions. Some say they just let more air and dirt in. Others say they are the best thing ever. Will be driving alost always on gravel not a lot of heavy pulling. Question is should I keep it or go to junk yard for stuff to change back to standard filter.

Joe
 
I like paper filters, too. My old John Deere rider with an 18hp Kawasaki has a paper filter covered with an oiled foam 'pre filter'. It's a pain to wash that foam and eventually it deteriorates to the point of falling apart. However, that Kaw engine has over 2000 hours on it and only recently started using oil. Rod hammers when it gets real hot, too, but it just keeps going.
 
It is a reusable filter . That is the selling point. If you over oil it, it can make you run too rich. You already have it so just buy some K&N oil.
 
I run them in two trucks and my Harley. No noticeable power increase. Just like the idea of not buying and recycling the paper filters. Clean and oil pretty simple.
 
Claims of increased power or increased economy are bogus on a modern computer controlled engine. Altering the mixture will result in the computer compensating or generating trouble codes. Increasing air flow will only result in more fuel usage.
When it comes to aftermarket "enhancements," I use this rule of thumb:
How likely is it that some small "mom and pop" outfit can "out think" or "out engineer" an engine or vehicle as compared to a $50 million development department in a multi-billion dollar manufacturer??

Just like the guy asking technical questions to an 8 dollar an hour parts clerk rather than asking a trained, experienced mechanic??

In my experience, I have learned that the engineers in designing an engine or a vehicle have to balance three main factors:
1) Performance to satisfy the customer.

2) Economy to satisfy the CAFE regulations.

3) Emission controls to satisfy the EPA.

So, logically speaking, is some kid in a garage in Anytown, USA smarter then the engineers? I think not.
 
They are junk. I wouldn't use one and I wouldn't buy vehicle that had one. Also I have seen the destruction that can be caused by improper cleaning. Some dumb shop hand cleaned the K&N with starter fluid and put it back in without drying it out. When he started the diesel truck the engine ran away. The engine and transmission were both destroyed. The flywheel and clutch came apart and cut the bell housing in two and some of the pieces came up through the floor of the truck.
 
The kid in the garage don't have to worry about epa or how to make it come together on an assembly line so ya most of them are better ideas than the engineers.
 
If you're driving mostly on gravel roads, get rid of the thing and go back to paper filter. K & N lets too much dirt through, IMHO. Maybe OK on pavement, where there's not much dirt in the air to begin with.
 
My Miata had one on it when I bought it--cleaned it a few times but the last time it was stuck so tight it was getting deformed from the force of removing it. Finally cut it off and went back to OEM.
 
thanks for that . Interesting test , I am not a fan of the K&N filters and other oiled filters and I think the person cleaning and servicing those type of filters could have a big impact on their performance, and in all reality the difference is small enough not to warrant spending the money on those type filters, any claimed HP gain has to be miniscule. Just stick to the stock filter and rest easy. I think the increased noise of the Aftermarket setups convinces people they have more power, just because they have more noise. The factory induction systems are designed to minimize noise
 
If no other mods are done to the engine system, then there is not much if anything to gain performance wise. As a component in an engine system that has many other modifications done, a KN or similar filter is very likely your only option.

I'm running one on a highly modified 2 liter 4 cylinder turbo engine (400+ wheel HP). It's at ~60k miles and shows no signs of decreased performance or significant wear. I'm kind of surprised that the engine has lasted that long regardless of the type of air filter on it. If I could only keep transmissions in it that long.
 
Ewwww, Oil bath air cleaners is a misnomer, they do not make air much cleaner at all. A GOOD dry pleated paper filter works best. I had a drop-in K&N filter in my diesel pickup. I cleaned it properly, re-oiled and as I was installing it noticed MILLIONS of points of light shining thru the cotton gauze. I ran to town and bought the OEM pleated paper element and installed it and have only used OEM since. I do use SuperLube synthetic grease to seal the oem filters like the K&N recommended, even included.

I had done a couple oil analysis's before installing the K&N. Silicon, (dust and dirt) was zero or one ppm. With the K&N, the two oil analysis I did were 3 & 4 ppm. The oil analysis I did when I went back to the OEM pleated paper element were zero and one. K&N passes dirt. Period! ALL my driving was on Interstates or major State or local highways and hard surface roads, no dirt or crushed rock.

Wish I could get two stage pleated paper filters to fit my two Farmall tractors. My new Cub Cadet Tank has a great molded plastic two stage in it's 27 hp Kawasaki engine. But it's set-up horizontal and I need vertical on my tractors.
 
I see them frequently in the dealership I work for. I have yet to see an intake with one of those filters that did NOT have a layer of dust on the clean side...
 
Live on rock roads had one on my pickup and my wife's Cherokee for not very long .When you can see daylight through the screen holes no way can that keep the dirt and dust out.
 
I have the same truck and put a K&N in it and our '97 Grand Cherokee. No real difference in mileage but they both seemed to run a tad stronger. I think they probably made a difference in carbureted engines but with the newer ones, no. If the air flow is restricted or increased the brain will adjust fuel mixture and timing to compensate.
 

I have a AFE oiled filter on my Super Duty, basically the same as K&N, I've had concerns about how well it filters but using the truck on the farm and on dusty roads has me cleaning the filter every 3-5 thousand miles. It'll be full of dirt and starting to suck in each time I clean it. I decided it's not worth the hassle of having to clean the filter so often and will be converting back to a stock type filter in the near future.
One of my other trucks still has the stock filter system and I can get 20,000 plus miles out of one of those filters.

We put a K&N on one of our FD brush trucks, each time we came back from fighting a field fire the filter would be completely full and need cleaning, we changed it back to a stock type paper filter.

In my opinion oiled filters and dirty conditions just don't go together.
 
No one has mentioned this but it is a proven fact. The oil from the filter will coat the little fine wire sensors in the MAF sensor just down stream from the filter and then the dust will stick to them and insulate them from the air flow. This gives the computer the signal that there is very little air flow going past them and thus, leans out the mixture, sometimes even to the point of sluggish to no acceleration and backfiring from lean mixture. Put it to the floor and you will go no where. Slow acceleration and you may not even notice it but on a '99 Sub (350 Vortec) in low range 4wd, on the gravel, will not even spin the tires when put to the floor. My advice to anyone using an oiled filter is to take it apart and spray the MAF wires once every 6 months. Bets to leave the K&N to the racers who will rebuild every year anyway.
 
Maybe if it was over-oiled. I've never seen that on the engine I mentioned in an earlier post. It has a GM 3" MAF just downstream from the K&N.
 
Bare in mind that even the cheapest Briggs & Stratton push lawn mower engine has abandoned the oil wetted air filter for a dry paper filter.. Much more efficient.
 

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