I recently replaced my air filter with a K&N, box says all over it, increases MPG blah blah.. it seems like my truck is getting lower MPG WITH the K&N anyone else had this problem? Power output seems a little lower as well...

 

Which filter did you get? The drop in K&N or the replacement (no more airbox) Fuel Injection Performance Kit? There was a thread about this a few weeks ago with a link to a site which reviewed the different filter setups, and showed that some reduced gas mileage while others improved, rather interesting. Heres the site:

http://www.performanceunlimited.com/...ircleaner.html

Hope that helps!

-Chris

 

I've never used anything but the drop-in filter.....which in my opinion isn't going to affect mpg "much" at all....one way or another. I use them because I believe they do give a better air-flow.....which is better for the motor.

I'm sure there are some here that disagree with that.......but....I feel comfortable with it.......and it's my truck......

Nice chart Chris.....I hadn't seen that one

 

I do know that the trucks I tried the air ram intakes on seemed not to run any batter once the out side temp went up . After all your sucking nothing but hot air. With stock setup you at least get some cool air .

The Maf trucks are really affected because the air sensor is moved to air box . I don't know if the ecu is for the cooler air or what but my mileage went down.

But they do breath better . And has to help somewhere.

 

I have used the K&N drop in filters in a number of applications, including two motorcycles. My general opinion is that the MPG's have not changed much at all, either good or bad. My F150 seemed to benefit the most from the K&N though as there was a noticeable "slight" improvement in MPG's. IMHO the most important tool that you have in getting good fuel economy is your right foot - you know - the one that you stab at the gas pedal with!

Cheers!

Mike

 

I know this may offend many but I personally WILL NOT run K&N in ANYTHING!!!!
I have seen too many trashed motors from the lack of small micron protection of the K&Ns They flow better but do not protect well enough in my opinion... One motor was on a custom built Harley that NEVER was run anywhere but pavement and the pistons and cyl walls were DESTROYED in 8,000 miles... Motor was brand new and never had any thing but a K&N! These motor parts looked like they were taken off a dirtbike after a BAJA 500 race with no air filter. There was noticable grit in the carb troat and the intake.
I will stick with either stocker type paper filters or the amsoil re-usable. It protects better than stock flows better than stock but not as much flow as K&N...
Brent

 

Well I'm not going to say that you're wrong because, well, what the hell do I know? But how could all these millions of people who use K&N filters (including people that know A LOT MORE about cars and trucks than ANY of us) be wrong? I mean, you would have thought that SOMEBODY would have noticed a problem by now and K&N's reputation for improving the performance and life of engines would have been marred. This has not been the case, so one freak incident with a HD that had junk in the combustion chamber (for god knows whatever reason) is not going to phase me, sorry to say. But to each his own. This is the 3rd truck that I have personally owned with a K&N filter and I've always had nothing but good luck with them. Just my .02

-Chris

 

K&N is snake oil you are much better off staying with the stock filter and just changing it regularly. the K&n and Amsoil especially after being reused a few times are more restrictive and pass more dust

 

I just installeed a K&N intake on my 88 F-250, havent driven it enough to notice anything yet more then some increased HP, as I am waiting for for a couple other mods, and my exhaust first. I have run just the K&N filters in my cars and had great luck! But the whole destroyed pistons and cyl walls makes ya wonder.....yikes

 

Had I not known the bike and it's owner from the day he got it delivered I would not say what I did. The other vehicles with bad motors could have had excessive wear to begin with and many were driven in dusty conditions and the owners may not have done the required maintenance...
As for the many others using them... Many are nearly pro racers and do much more maint. than most of us and many of them have new parts to drop on for any number of reasons...
I have seen (actually owned) a demonstration device that showed the grit allowed through different air filters and the KN allowed FAR MORE than any filter...
I would say if you are going to run any reusable filter you buy 2 filters and 4 pre filter foams...
It makes maint. far easier if you ain't gotta put the truck out of service for several hours for cleaning and drying time... Just remove dirty filter drop in the cleaner bucket and replace with the clean one. After you notice some build up on the foam remove and drop in the bucket and put on a clean sock...
As for me I will run paper filters...
Brent

 

I see trucks with engine damage every day down here where the owner thinks becalus he is going to Baja that he should put on a K&N. If you off rode down here you are going to see lots of dust. bring extra filters you may use one every day.

 

I would buy a case of paper filters to head down there!
Foam prefilters would likely help in Mexico too...
Brent

 

More maintanence than us?! I refuse to believe it!! Well all this talk of dirty filters has inspired me and I'll be cleaning my K&N this weekend. Won't be changing her out to a different filter though, call me crazy

-Chris

 

I would like to get my hands on some Foam prefilters. cat get them here, but I make some that help a lot. they are a little restrictive but work fine off rode at low RPMs and not nearly restrictive as a plugged paper element. I am working on building a snorkel with a tractor type centrifugal pre cleaner for my F150.

 

Well all the racers I know do maint. after each race... I do maint. after each year or 3...
this truck I bought had no air filter assy. on it so I bought the ONLY one that would fit the single barrel carb... a 3.5 inch by 2 inch or so and that sucker clogs after 4-5000 miles since much of my time is spent on red clay roads...
Brent