I made my first purchase today for the new rig I bought a K&N air filter. I've heard mixes reviews about it helping MPG's. So I'll keep u guys posted on how it goes. I know I should just a 5 star tuner but funds are limited!!*

 

Some swear by them, others are skeptical, and a few will tell you that the oil from the filter will ruin your MAF sensor. Personally, I have them in all 3 of my vehicles and I know for a fact that I gained right at 1 MPG on each. K&N did a ton of research to dispel the myth about over-oiling affecting the MAF sensors. Here's the link for the videos.

 

My homies wife drives a V10 01 Excursion and drives 60 miles round trip to work and bout 90-95% on the fwy she got 2-2.5 extra MPG

 

So far I'm down less than half a tank and I've gained 1 MPG so far which is cool that gives me a extra round trip a week to work hahaha.

 

So finally had to fill up today. It was almost a week in between fill ups bit I gained 1MPG and got 30 more miles.* And I actually drove it hard this week!!

 

K&N has done extensive research that shows there was minimal to no oil on the MAF from the filter. Of course it was internal testing, but it goes for something.

 

I have managed to overoil my k&n on the mustang once, though it was more of a, wash it, oil it and put it on right away type deal, I more or less expected it, but I needed to go racing that weekend and was looking for a new best. Didn't happen

I kind of wish JLT would come out with a CAI for the V10, kind of how they have the one with the giant K&N filter for the 3v 5.4.

 

Is that compared to a dirty el cheapo paper, or a brand new quality paper filter?
Comparing apples to oranges is kinda meaningless...

I replaced the K&N that came with my truck with a Napa Gold and saw no significant change in mpg. Maybe .25 mpg improvement, but that is way too little to call significant.

 

compairing to the stock one

 

Dating back to 1997, I have the docs from Ford on my new (at the time) Cougar Sport (4.6), specifically calling for the removal of the K&N filter after replacing an oil contaminated MAF 3 times....

I did not touch the K&N filter, right out of the box & into the 3 week old car- and despite K&N being notified including in person with all documents (including the original purchase receipts as ordered directly from them), they refused to accept Ford Engineers reports and honor their warranty- which I simply asked to return the product and recieve a refund.

I would avoid oil impregnated filters. While they have their purpose in off-road applications, Ford/GM/Dodge all have “watch-out” bulletins where the oil has contaminated intake sensors. - they even have a training video for the techs on this (flatratetech.com) .

If you look at the flow data, WIX HP filters flow 98+% of K&N and have a much smoother flow post filter plus excellent filtering, for a fraction of the price! The OE’s have an excellent air intake system. What many view as an issue (is the plastic intake tube with its noise canceling design) actually increases air pressure. It is the same hydraulic concept used by fire fighters creating water supply where psi is low. By having the air cross the path at a 90 degree angle, the pressure is increased proportionally. Fire fighters use what is called a “4-way valve” or “Blake Valve” at the hydrant where the water is cycled through the fire engine (pump) and sent back into the valve crossing the water flow at a 90 degree angle. In this case it also acts as a sound canceling device! At low speeds, this can reduce the flow a tad (which is what most “feel”), but in terms of peak hp/tq, a good high flow filter is all that is needed. You can use a WIX OEM HP replacement filter in the OEM plastic manifold box and either remove the plastic tube and replace it with a piece of pipe/hose, etc or remove the tube completely and replace the tube by building an air ram type intake into the air box manifold (where the pipe use to attach)- make sure it terminates above the fan shroud to avoid water intake or fan induced pulsations

 

K&N has been been known to grossly over oil filters at the factory. The filters really do not require much oil.

 

If you live in the pacific northwest or damp rainy climates the K&N filter can work well for you. If you live in the southwest deserts or dry dusty climates you may want to stay with a quality paper filter. If you take a K&N filter out and hold it up to the sun you will see thousands of tiny holes that you can see light through. No big deal if you are looking to catch large grains of sand but the fine air born dust can make its way right through and you will find a nice coating of this fine dust throughout your intake tract as I did on mine. This fine dust is what causes premature engine wear and decreased longevity. You will also find the engine oil get dirty faster using this filter. The K&N filters are most efficient when covered in dirt and that is because many of these tiny holes are plugged and the dirt is held there by the oil. The K&N is designed to be a performance filter for racing by passing more air thus increasing performance but everything good has a price and that is it lets more dirt through as well. Many articles have been written on these filters and will be worth reading before you decide to buy one.