Correct if proper care is taken of them they are good filters.
Harley Davidson puts K&Ns in their Screamin' Eagle motorcycles from the factory
and they are the top of the line big $$$$ Harley's.

I off road a LOT in my truck and have sent in for an oil analysis. This is using a K&N drop in filter is extremely dusty/dirty conditions. When I spend a day off road under-hood will have piles of dust/dirt about everywhere and the filter is filthy. The report shows the filter did it's job.
Here is the report. This is first hand experience, proof, not something I read somewhere.

 

Do a google on "Turbo Dusting". Lot's of articles on turbo damage from the dirt/oil
a K&N passes.

Here is an article stating that a K&N will pass 100 micron dirt particles, a paper filter is 20 microns:

http://www.benzworld.org/forums/w211...r-filters.html


This photos of paper vs K&N filter media confirms that:


OEM Paper Filter Media:





K&N Filter Media:




And more proof. I did this experiment a few years ago. I covered a plexiglass tube with K&N filter media, and OEM paper media. I used carbon resistors as a
smoke source, and as you can see the smoke passed right through the K&N
media, but the paper media blocked the smoke:









Besides, as Kris has stated, there isn't any performance advantage of using a K&N filter. You could use chicken wire for a filter, and there wouldn't be any performance improvement over OEM paper filters.

 

Hey Robert did you change the spark plugs on this truck? I am not sure if you are up on the plug problems on the 04 to 07 F150 with the 5.4 L engine. Look in the forum for more info.

 

I'm getting about 14 mpg, average, haven't driven mine a lot since I bought it, but... 14 mpg is a lot better than what I get in my work truck, which is a tractor trailer, it gets about 6 mpg with a tail wind, lol!

 

Quick bump since its been a while since I posted on here, I got the Edge evo tuner and my mileage has gone up quite a bit and my truck doesn't feel like a dump truck like one member mentioned. The average mileage displayed by the Edge is usually around 16-18 highway and when I drive in town it drops to low 15s.

Overall I'm very happy with this purchase and I'm getting 720km+ to a tank which is much better than under 500km I was getting stock. The biggest difference I think is that I drive normally and I'm not in a rush to mash the gas, I pay a lot of attention to the APP senor/engine load.

Sean

 

14 mpg

 

I average 18.5 on a recent weekend trip. Mixed country roads and interstate.

2005 5.4 XL SC

 

Not bad.

 

I was happy. I have been getting very similar mileage to what I was getting with my 4.0 Ranger on 31's.