Air filter cfm?

[fe66comet]

How is cfm calculated on a pleated washable filter? I am looking at a K&N 4.375/6.5/7 taper pleated filter with a 5" flange. I looked on the K&N site but no info there in the filter specs?

[rockittsled]

http://www.knfilters.com/filter_facts.htm#SELECT

http://www.carcraft.com/techarticles/ccrp_0409_air_cleaner_assembly/viewall.html

[fe66comet]

Cool thanks dude, I knew there was some info on the K&N site but couldn't remember where. Thanks

[Qikbbstang]

on the K&N link above and in less then ten seconds found heap-deep bullshit.  Wonder why K&N uses the term "hypothetical"  24-hour off-road race to further the point" ?   ..I can say it..Fits right in with their Nominal Filter Ratings   

"In a hypothetical 24-hour off-road race to further the point, a properly sized K&N filter will see the racer through to the end with cfm to spare. The equivalent disposable air filter, on the other hand, will need to be replaced with a fresh element to ensure the engine has an adequate supply of air to complete the course.  A K&N will provide excellent filtration without sacrificing air flow for a longer period of time — that’s performance with value. "

[fastback 427]

I have three buds working as diesel techs at two different ford dealers and the first thing they told me was to take the k and n off my powerstroke when I bought the truck. Said it causes cylinder wear due to poor filtration.

[fe66comet]

As long as a pleated cotton element is maintained properly it is 90% efficient, a paper element is 40% efficient. This all translates to better filtration at a cost of airflow in the same area. The pleated filter will require more area to go the same distance bit will protect from dirt entering the engine to a finer particulate count.

[Drew Pojedinec]

I have three buds working as diesel techs at two different ford dealers and the first thing they told me was to take the k and n off my powerstroke when I bought the truck. Said it causes cylinder wear due to poor filtration.

Being that I'm technically a kind of diesel tech, I gotta ask the tech questions.....
Do they have oil sample results to back this up?
I feel that a "properly" cared for K&N style filter doesn't cause any more issues than a paper filter.
For industrial usage, I prefer paper filters just because they are relatively idiot proof (if there happens to be nothing but idiots around)

On the boat I work on, I have 5 large diesel in my care and keeping.. we send off oil samples once a month no matter the hours.  Two of them are C4.4 generators with dual paper filters.  They typically show twice the silicone in the oil sample as the mains (this has been a current trend over the last 5 years).  The larger main engines run "AirSep" cleanable filters that are just like a K&N. 
They all take the same oil, Delvac MX 15w40 and it is all stored in the same tank.  All oil is changed at 500hours.  The gens hold 3 gallons or so, and the mains hold 35-40 gallons.

I'm certainly no expert at this, but just from my observations and the results with these engines over the last 5 years (14,000-23,000 hours) I only know what I've seen.... this points to the K&N style filters actually doing a better job at filtering, and they never actually show a restriction, I just wash and clean them every 1500hours.  The Paper filters are changed every 1,000 hours.  I can assure that, as I am the only one that has every done any of the maintenance on these engines since they left the factory.

Drew

[Drew Pojedinec]

Ohh and whilst on the subject, a little story of my often horrifying life.
Bout 6 months ago, I had a minor fire in the engine room.... mains were running as was the stbd generator.

I noticed the problem about 60 seconds after it started as I was outside working... When I got downstairs the paperfilter on the generator has already clogged enough with smoke to stall the engine out.
Trying to find the source of a fire and put it out in a small metal box underwater sucks to begin with... it sucks even more when the lights go out and the fire pumps don't work anymore because the generator just stalled out.

In this scenario I prefer the k&n style filters, as the mains were still running just fine.

[fastback 427]

I don't know if they have any actual samples or physical proof but it sure bummed me out as I have k and n on all my rides. And they still are. I would guess most k and n filters are not properly cleaned and oiled as directed.

[Drew Pojedinec]

I'd buy that....
I've seen people hosing them off, spraying wd40 on them and calling it good.

[LargeRickhead66]

Having been involved in off road racing in the 70s,on a Bronco team, my experience was all good with the K&N filters.  Until we learned about K&N filters ( from Parnelli Jones ). We would run a Filtron foam filter over a paper filter. After a lap or two, or after a few check points, the engine would start running very rich, puffing smoke like a diesel. We would then pull the foam outer filter and run the rest of the race with just the paper element and usually by the finish it would be clogged up also.
The K&N filters never had similar problems, and we never experienced undue engine wear or even dust getting past the filter.
 We even won a couple of races....

[Lenz]

I'm thinking just put in the biggest filter that will fit.  When I brought my Galaxie my first move was to ax the 1" tall oval cobra unit (cute but not effective!) and replace it with an ordinary 4" STP filter on a 12" base with a 2" spacer over the carb.  Huge difference (I know, fugly but it made a big difference and I had the room!).  The thing could breath!  My test drive involved an over-rich condition that was easily diagnosed as not enough air) I've heard good and bad about K & N, so it is indeed a matter of preference, but I say go cheap and haul as much unrestricted air in as you can .

[fe66comet]

When I ran a k&N on my off road motor cycles the differance you could see in the Nic-cell plating. After a summer of riding with a paper vs the K&N, the K&N caught more dirt.
 

[KMcCullah]

Hey let me on this hijacked K&N train. I've been running a 14x4 K&N with the K&N hat on my truck. They seem to work fine but you have to pay attention to them. Last summer I had a single backfire through the carb. Just one big pop. It was bad enough to blow one of the power valves even though the carb base has the little check ball preventers. Anyhow the K&N hat had a fist sized hole burned through it too. So beware, they don't seem to tolerate fire very well.   

[fe66comet]

I would think any element would cook if it were exposed to direct flame saturated in gas. I would think an arrestor would help.