I'm thinking of getting one of those bolt on high flow air filter systems to replace the stock system on my '96 F-250 7.5L 460, like one from K&N.

My friend says that those systems let more dirt in along with the high airflow, and shorten the life of the engine. Any thoughts? Do these systems decrease or increase gas mileage and do they boost horespower?

Thanks,
Woody

 

they don't let more dirt in and they don't shorten the life of you engine. aftermarket intake may be made out of thin gotton but they are coated in oil to catch the dirt. Intakes increse the life of your engine because they can breathe easier and more efficiently. they can boost hp by as much as 10hp and also increase you gas mileage.

 

Woody -

Some people report increased power and mpg; others say no difference. Some also report dirt in the intake tube and throttle body, plus oil fouling of the MAF sensor; others report no problems. Just about everyone mentions more intake noise when you romp on it. Also, servicing a K&N is not a 2-minute job; you need to let it dry before oiling it.

I use a K&N on my boat, but I would never run one on a street machine and take the chance of PROBABLE increased dirt ingestion. JMO......and it's your truck.

Steve

 

Woody -

Take a look at www.bobistheoilguy.com/airfilter/airtest1.htm - it might help you decide.

Steve

 

See my comments (post #5) in this thread:
https://www.ford-trucks.com/forums/s...d.php?t=302488

 

I used to run K&N filters with Outterwears pre-filters on my dirtbikes and ATC's untill one day I removed the air snorkel from the ATC and it was full of dirt. I service the air filters often, after every long weekend of riding or after every other short weekend, so the dirt was not due to running dirty unserviced filters. I hadn't noticed the dirt in the snorkels before when servicing the filters because the dirt wasn't collecting up by the air filter end of the snorkel, it was collecting downstream before the carb, settling into the recesses of the corrugations in the plastic snorkel at that end. I had taken the carb off and that's when I noticed the dirty snorkel and carb inlet. I switched all bikes to UNI foam filters and have noticed cleaner air snorkels on all of them and no decrease in power whatsoever on any of them. I will never run a K&N air filter on anything I own again. It costs too much money to rebuild an engine because of sucking in dirty air. You may get away with a K&N on a vehicle only driven on the street, but even then I don't like them. I run the stock pleated paper filters on my trucks and they do fine.

 

I hear lots of different things. I know on my B2, it's whole life it's been run on regular filters from Autozone, and I looked in the tube that goes from the airbox to the TB and it was dirty, there was also dirt on the inside of my TB. I know some dirt gets in, but I don't know where, I have tight fittings and everything. I don't see why not to run a K&N.

 

It's not simply a matter of *whether* airborne contaminants will get it; it's *how much* the filtration technology allows to pass. I wish I'd kept a link to a study I'd seen a couple of years ago, in which K&N was determined to let just about twice the amount of silicate (think sand) contaminants deemed to be of the size that will harm an engine. I think, but am not at all sure, that 25 microns was what was tested for.

This has been stated before, but it bears repeating: K&N filters were originally designed for racing applications, where engines would generally get torn down way, waaaaay before accumulating enough mileage for intake contaminants to be a factor. If you desire longevity from your engine, however, K&N is to be avoided unless you live somewhere like Antarctica.

 

The new FRAM Airhogs.. like the K&N's or what?

 

I haven't seen the Fram, so I can't comment...but in general, air filters are a pretty simple concept. More air flow comes from more surface area to the filter, or a more porous/permeable filtration medium. Putting it another way, letting in more air generally lets in more of the bad stuff, too. There may be some exceptions, like the Cyclone pre-filter, but I've heard mixed reports about them, too.

Unless you really have compelling evidence that you need more flow from your air intake, it's probably best left alone. Certainly it wouldn't be anywhere near the top of my list for performance upgrades.

 

FRAM air hog, is a K&N in a different box. Same set up, different name. SAME issues

 

10 horsepower isnt squat in a F250, you wont even notice a difference.

 

I'm not going to say this is wrong, but what about better technology, better product? Technology offers a lot, say your OE muffler quiets your exhaust down to a certain dB range, and an aftermarket muffler quiets the exhaust down to the same dB range. Most likely the aftermarket muffler is going to free up some horsepower by the way it was designed. Why can't two different airfilters both filter the air, but one have better flow?

 

One filter *can* have better flow...it just won't do it without either 1) a larger filtration medium area or 2)a more porous filter element. The first option is fine, though I don't think it applies to any of the big-name filters out there, and 2) is a direct threat to engine longevity.

When considering engine mods, it's pretty useful to remember that the manufacturer hires some pretty smart people to design their engines and fit together a family of components that will work pretty well. This is partly why I find the claims of some of the aftermarket people to be ludicrous. If a simple task like adding a K&N air filter did anything meaningful to horsepower...don't you think the manufacturer might be just a little tempted to put on something like that themselves?

When you do make engine changes, you have to consider the whole engine if you want to see meaningful results. Air intake, fuel injection, cam timing, cylinder size (and compression), valve size, exhaust diameter, length and restriction are just a few of a dizzying array of variables that have to work together if an engine is going to perform well. Thinking that one can achieve a substantial benefit from slapping on a $40 aftermarket part with universal applications is beyond simplistic.

 

RomerB2 -

From what I've read, paper filters are about 99% efficient; oiled cotton/foam run 96-98%. That might not seem like much, until you consider how much air is ingested to burn a tank of gas. Like mzimmers said, you can't increase airflow without a decrease in filtering efficiency if the size remains constant.

Some people swear by K&N and some just swear at them, so........to each his own.

Steve