Had K&N, but got rid of it. Saw no gains, my MAF was oily, and after 3k miles there was debris in the throttle body even though I had just cleaned/charged the filter. Protect your truck for the long run, and just buy regular air filters....

 

I had a K&N drop-in in all of my vehicles; Grand Cherokee, Mustang, Ram, and Wrangler, up until about six months ago. I read up ona K&N vs. a Wix air filter and I was shocked. Although aK&NDOES flow more air, not very much more than a brand new Wix filter though, the K&N also allows more dirt to pass thru. It gets worse after each wash.
From that, I decided that the marginal increase in air flow was not worth the increase indirt making it into the motor.What is the primary purpose of ANY filter? To trap harmful contaminants. The more trapped dirt the better is my way of thinking.

 

thats what i did...i bought a ebay intake for $25, went and bought another peice of pipe to route it down behind the headlight and i put on a True Flow cone filter...i also double wrapped the tubing with insulating tape and foil tape...the new cone filter was the most expensive part of the whole thing and it works perfect...dont have to oil it or anything...i love it

 

Duramax volunteer owners did one of the best studies comparing drop in air filters. Unfortunately it was taken off the web, but a copy of the webpages are in Google's 'Wayback Machine' internet archive:

http://web.archive.org/web/200412082...011/SPICER.htm

To see the pictures you have to 'right click' on them, pick 'Properties', and then to a Wayback Machine search on that .jpg image to find the copy stored.

For example, here is the 'Initial Restriction' image:



The above test indicates that the KN drop in has less than 2 inches of water restriction advantage over typical paper filters.

How beneficial is 2 inches less restriction?

Well you have probably heard that the air pressure at sea level is about 14.7 psi. At most places 800 feet above sea level the pressure drops to 14.5 psi. There is about 28 inches of water pressure for each psi, so the pressure of the atmosphere measured in inches of water is about 400 inches.

{if you had worked as a mining engineer you would have that number memorized since it also tells you how high a pump can 'suck' water upwards)

the KN drop in would then give about a 2/400 advantage
or about 1/2 %.

Most people can't feel a 1/2 % gain with their famous 'butt dyno'

But the story is not over.

Look how fast the KN 'blocks off' as it picks up dirt:



Nearly all the aftermarket CAI have this
'qucker block off'
problem from the dirt they trap because they use a oiled gauze cone filter ....including the Air_Ram, the Volant, Airaid, etc

Have you read in a magazine somewhere that xyz cold air intake had a gain of so many horsepower over the stock filter?

Go back and re-read the article now that you have seen the initial restriction graph and the 'quick block off' graph.

Did the magazine testers compare a
BRAND NEW STOCK AIR FILTER
to the new out of box xyz cold air intake
or
did they dyno a used, old, mostly blocked off stock air filter
against this super dooper whiz bang CAI?

You now know how to rig a dyno test without actually lying in the text.

You also now know how a poor magazine writer,
who usually gets paid by the magazine less than $25,000 per year
can make a quick $5000 under the table cash payment from the CAI maker
that won't be reported to the IRS or his magazine editor.

 

I give less than a flying freak which accelerates better. I give less than a flying freak which one has more hp. I give a flying freak about improved mpg. Off of 2 tanks I am getting about a 2.6 mpg increase off a K&N filter over the stock filter. While this is not the most scientific because I don't have the time to drive the exact same route through 2 tanks with each filter, even if to was possible to keep all the variables the same. I am trusting my math in both my onboard computer and my math skills which as long as I have a calculator I will prevail at math. K&N Filters = Great

 

If you do a proper scientific test
there is no MPG gain from a KN filter.
Even KN engineers will admit this if you talk to them
at SEMA shows.

The KN advertising says:
"Customers report that MPG increased"

Notice the difference with an ad that says:
"Independent tests confirm that KN filter improve MPG"

Note that KN does claim that independent tests
do show that high rpm maximum horsepower does increase slightly.

If you all you do to check MPG is test
tank after tank
you are going to get 'natural' results like this
where one tank can be 13.5
and the next 15.5
with no change to the Ram pickup:

====
Here's the results of several tanks of gasoline I kept track of with the OD
either on or off in city driving. After each tank fill up, I alternated
keeping the OD on or off.

I have since made 3 more 300 mile long mpg tests in city driving since i
posted the original 6 tests. My test results now look like this:
-----------
OD turned off runs:

7-19-00 14.32 mpg Amoco87
7-29-00 15.17 mpg Amoco87
8-08-00 14.23 mpg Amoco87
9-08-00 13.53 mpg Amoco87
---------------------------------
average 14.31 mpg

OD turned on runs:
(these were run inbetween the runs above)

7-12-00 14.16 mpg Exxon87
8-17-00 14.25 mpg Amoco87
8-24-00 15.49 mpg Amoco87
9-01-00 15.03 mpg Amoco87
9-12-00 14.35 mpg Amoco87
-------------------------------
average 14.66 mpg

As you can see, so far the OD on/off difference seems to be small with a
slight 0.3 MPG edge to leaving OD on while in city driving. That is about a 2%
difference.

Note also how much the MPG jumps around. All realworld tests have 'random
variation.'

If I had done just two tests, and had by chance gotten the low 14.16 for the
OD on, and the high 15.17 for OD off, I would have falsely concluded that OD
on really hurts in city driving.

To get more reliable MPG numbers for Rams in city driving you need to do
multiple tests in a before/after/before/after sequence. Even better would be
to do SAE/TMC type IV testing with two or more vehicles following one another
'convoy' style.

Most fraudulent MPG improvement devices continue to sell because of this 'jump
around' MPG during normal driving.

If a MPG device DOES NOTHING AT ALL, out of 100 people who try it, 50 will
find that their next tank of gasoline got them better MPG, and they will then
boast what a wonderful device they just bought.

Out of the 50 who get worse MPG on the next tank, quite a few will be a little
ashamed they got gypted and stay quiet, and only a few will be brave enough to
post that the device is a fraud. Some of these will say: "Maybe I did
something wrong and I will check the MPG on the next tank and will drive more
carefully." Half of these will "by chance" find better MPG on the second tank
and get the percentage reporting better MPG with the worthless device up to
75% !

 

Cool with me. Believe what you want and I will believe what I want.

 

I have heard on the diesel's that k&n filters right out the box caused or can cause problems. Some have stated when the filter is pre oiled at the factory they use to much oil and this is what is causing the problem.

 

I did a drop in for the biggest reason: I got a barely out of the box Ebay deal for $20 shipped after finding out that paper replacement filters for the Ram are close to $20 anyway!

 

The only thing a K&N drip in will do for you is remove cash from your wallet and allow more dirt into your engine.