First a little back ground. I bought my SCab F150/5.4 new in '06, ran it for a couple of months, then dropped in a Air Aid filter element. I drive about 200 miles per week, always the same route about 50% at freeway speeds and 50% in town. I fuel up at the same station always. I was getting 14.5 to 15 miles per gal constantly, using 87 octane regular gas. Last month, I decided to clean the filter, and reinstalled the OEM paper element so I could drive the truck. At that point I forgot to change back to the oiled gauze and ran about 800 miles on the paper, always refueling at the same station. After a check of the miles driven, vs the gallons consumed, my mileage has increased to between 16.5 to 17 miles per gal. The truck is bone stock. Can someone explain this? I always thought the gauze filter element was less restrictive than the stock paper element, and should return a better fuel economy. The gauze element was cleaned periodically using the correct procedures, and not over oiled.

 

Airaid filters aren't that great to begin with. If you want a good performing filter, look into S&B, K&N, AEM or Volant.

 

I got the Airaid filter on the advice of Summit Racing, because K&N didn't list one at the time. Is there a difference between the two? The Airaid looks just like the K&N except for color.

 

Performance filters do NOT net higher gas mileage. Better driving habits do (not insinuating anything on your part). The air raid has more CFM. The MAF senses more oxygen and contributes more fuel to the MIX. The OEM filter has less CFM ergo the MAF will sense less oxygen and contribute less fuel to the MIX.
I did this multiple times in my old truck going between a K&N cone and the OEM cone filter. I got so sick of crappy around town mileage (the 3.08 rear end didn't help either ) I reverted to the stock filter and consistently saw a 1.5 MPG increase.

 

In my pursuit of answers to my air filter question, I ran across this test. It was done on a Chevy diesel, but I believe the results would be about the same regardless of vehicle brand or fuel. The tests was conducted in accordance with ISO 5011, (formerly SAE J726) standards, so I believe they are valid measurements. It appears that the oiled gauze didn't fare all that well when compared using scientific procedures and standards.
http://www.duramax-diesel.com/spicer/index.htm

 

So without programming, I'm seeing more and more folks sticking with a good quality paper filter vs a drop in K&N. I've read about the filter from Amsoil that looks pretty good for about $40. Does anyone have any experience with these or any other type of filter?

 

Decided on a drop in AEM synthetic fiber filter that is oil-free. Turns out that K&N recently bought this company. Anyone else use these? I am curious to see how it performs, thinking it will be no better than paper filter, other than you don't ever have to buy a new one. The AEM CAI is over $200 and the salesman/owner said in the real world you can only expect about a 10HP increase over stock. IMO that is not worth $200 plus dollars when you already have a 300+ HP motor. I combined that with a Flow-Pro SI/SO 14 inch muffler, staying with the 2.5 inch exhaust and a new tip. Filter was $38 and the exhaust was $160 out the door; not much louder than stock.

 

I still average 17-18 MPG on my 5.4 3v with 3.55 gears and over sized tires (edge calibrated) on heavy *** 22's with my k/n drop in. All this super duper scientific bench testing mumbo jumbo and myth blah blah about this and that is a crock. Real world testing is where it's at.