Just took my 1st long trip with my 2012 FX4 Eco-Boost. I've been a big fan of K&N air filters (just the filters) I've put then on all my vehicles and usually get a 10% mileage boost. EVERY Ford service advisor and Tech, told me NOT to use this filter as it would screw up the mixture and the mass air flow sensor. The K&N rep assured me that it would do no damage....So Minneapolis - Chicago about 450 miles cruise set at about 73mph. About 95 degrees temp, light wind each way. With the K&N filter 20.5 mpg. Stock Ford air filter 18.8 mpg. 3.73 FX4 axel. I was expecting a bit more mpg, but still much better than my Trundra with the 5.7 which never got more than 15.5. Any thoughts/comments?

Mark

 

Not bad for 73mph...Im thinking of a drop in replacement for mine as well, had the AFE entire system on my 05...Any extra grunt?

 

check out the afe stage 2 system, looks awesome!

 

I belive the issue with k&ns on a turbo is small parlicles getting by and damaging the impeller wheel of the turbo. When I had my powerstroke that was always a hot topic and hardly anyone used them. A n/a engine doesn't have the fragile turbo and just burns the stuff. The wheels in a turbo are very thin and tolerences are very tight, plus they spin fast. But that is a good gain.

 

^^^^^^^true^^^^^^^

 

Would you still avoid using one on a standard FI motor?

 

I'm no engineer but I understand the logic of the argument and would use one on a n/a or supercharged motor. However not a turbo motor. But that's just my opinion based on what I've read.

 

Dirt doesn't burn at combustion temperatures. It also collects with oil on the MAF sensor element, and throttle body.

Bottom line, they shouldn't be used on a NA engine either. If the K&N lets dirt pass on a turbo, they will let dirt pass on a NA engine also.

 

YUP......the OEM filter isn't restrictive, and filters well, so why take a chance with a K&N, known to pass dirt and oil.

 

I guess you don't oil a K&N drop in filter do you? But a cold air setup that you oil may be a safe option, not sure.

 

Yes, you do, but it is not a problem if you do it correctly. When they say lightly, they mean lightly. I ran one on my 2005 5.4 for 135,000 miles with no problem at all. When I sold the truck, still did not burn oil and ran great. Saved a lot of $$ by not having to replace the filter.

 

Same here on my 04. A lot of people on this forum bash K&N, but mine worked great. The only thing I didnt like about it is the down time when cleaning the filter, it takes FOREVER to dry, for that reason I am maybe looking into a syn fiber washable.

 

Did not burn oil? Mine went through at least 1qt from day 1! Also, I am still considering a K&N but have a problem with over saturating! When you spray it lightly, how are you sure you got full coverage, in every pleat? That is my biggest concern!

 

I'm trading in my 2009 F150 with 96,500 miles on it this week. I only replaced the air filter once at 50k. Never added a drop of oil. My out of pocket was $16.30. I'm betting I spent less than you!



-Andy

 

you are not sure, and won't be. Just like most "performance" things, there is a tradeoff. You get more flow for less protection. Even if you do get every pleat, you still have poor filtration quality. If you want superior filtration quality, stick with a paper filter.

That does not help, but its not the main issue. There are folks out there that literally just use a piece of window screen clamped over their compressor inlet. Over time, with the use of a K&N, the impeller wheel gets kind of "sandblasted" looking but its still going to last you a good while. I have seen some that are pretty gnarly looking (from other things getting in there) that still "work" & "hold boost just fine" according to their owners.

A n/a motor is not going to "just burn it off" that dirt and grit is going to find its way to the cylinder walls, where it will increase the rate of wear there, as well as contaminate the oil where it will travel through out the rest of the oil passage ways. On the bright side, at least it won't have the small impeller fragments in addition to the dirt to digest.

The main problem with K&N type filters and why service reps tell you not to use them is because the oil on the filter ends up all over everything in the intake tract including sensors. The biggest problem is usually from the MAF sensor... the oil coats it, acts as a blanket, and over time fries it. The sole problem is not just that it shortens the life of the MAF, the mere act of coating it is going to cause false readings (low air flows - inducing a lean condition) which is obviously bad. Your IAT sensor on most vehicles is also down stream from that point - not as crucial but it is going to cause higher than true values to be read.

After you spend:
$50+ on your K&N
$10 periodically on your "recharge kits"
and $ ??? on a new MAF (hopefully you don't have to pay someone a diagnostic fee to diagnose the problem cause that's just more money)
How much have you saved? its ok though, cause you got 5hp extra for a while. That was worth it (and needed) right?

You won't see me running one in my truck.

K&N hate aside, I suspect you could go a long time trouble free from the oil if you do oil lightly AND you take the time to pull our your MAF and spray it down with MAF cleaner every 5,000 miles or once every engine oil change interval. ...but the poor filtration part of it you are still going to be stuck with.

To the OP (Mark S)...
do remember that the service techs in this instance are telling you not to use this because they see the problems that come in and often see the cause and the fix before it leaves. I am not one for trusting a service department and I take everything they tell me with a grain of salt... but they really stand nothing to gain here, they have no reason to be biased. If anything they should promote the use of them as it would in turn promote business.

The K&N Rep on the other hand is just that, a K&N Rep. his JOB is to promote and sell their products - of course he is going to tell you their product is superior and does not hurt anything. That's what sells his product and ultimately how he gets a paycheck.


Finally...
Ill leave everyone with these:

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

http://www.bobistheoilguy.com/airfilter/airtest3.htm