ok got off the phone with k&n and they said that there filters filter down too 3 microns while foam filters are 6 microns.. I guess it comes down to personal preferance. I have run a K&N for a while now with no problems.. I live in vegas where the fine dust is evil and is the capitol of dust and still no props. Maybe some of you have an intake leak on your intake hose... Just always check your intake boot.. Gabe opinions?? I also know that k&n will play there products up so the consumer buys... www.knfilters.com

 

I also think they may be playing the numbers up. They may be testing against a poor quality foam filter.

 

I would venture to guess that all manufacturers play their numbers up. I dont have a new filter yet, but I plan on trusting K&N.

 

I have a K&N, and i definatly prefer my stock filter better...

It's easy to see..

I did a water test, poured tap water through both filters, Water went right through the K&N, and the stock one help up alot better, but a little water still managed to creep by

Also, hold a K&N up to the light, and look from the inside-out, You will notice "holes" in the cloth fins.

Microns.... HMM... a K&N cloth filter is alot more "compact" than a foam one... could this cause it to haev more microns???

truth is... K&N filters are extremly high flow, and in my opinion, SUCK for off road use

anyone want a 400ex K&N filter?? excelent conditon 10 bucks

PS: the K&N says on the box (use the dirt buildup to your advantage) So your telling me to use what i am trying to keep out of my filter, to prevent anymore of it from entering the filter?? WHATEVER

 

I think that, in theory, the K&N is supposed to flow better because it has much greater surface area, not because it has bigger holes. If you took out the pleated filter material and stretched it out flat, it would probably have a good 3x more surface area than a foam filter. So, in theory, they could make the filter itself better (filter smaller particles), and still flow more. I don't know if it works out this way in real life, since I don't have a K&N on my quad, but that's how it's SUPPOSED to work.

Personally, I think just for safety's sake, I'll stick to my stock foam filter. I swapped a K&N onto my Bronco and didn't notice any power difference, and it's got a big-block 460 V8 (7.5 liter: 7500cc), so I don't think I'd see much difference on my 400ex either, since it doesn't suck down near as much air (or gas, haha).

 

I have always run K&N on all my off-road machines, and I have one on my GMC big-block. On my truck, a minor power gain but it runs a little cooler when pulling loads. On my 250R, I change the filter after about 6 hours use, I have spares and put them in. I ride Glamis a lot and the sand does not get through the filter. Keep it clean and oiled and it works great. For the $35 I spent on filters I'm really happy.

 

Well, I think that K&N will play up their numbers, there sure are an awful lot of people here complaining of fine dust entering the engine. Dust wouldn't be that much of a problem unless you ride behind someone a lot - I have been racing a lot since installing mine in really dusty conditions, as you probably know, mine has been sucking dirt and is now due for a rebuild.

Check out CT Racing's tech tips, they will even tell you that a properly functioning and well oiled K&N WILL let dust in. What do they have to gain by telling us this? It's just not worth it in dusty off road conditions. Make your own call, but mine's going up for sale on eBay...

 

gabe, are you sure your due for a rebuild?? how many hours of extremely dusty conditions could ruin an engine? I am starting to worry about mine now.... dude your scaring me,

 

hehe... Like i said always check your intake. you feel grit...time for some work

 

It both smokes on acceleration and uses oil now, which it did not do before, this all happened pretty rapidly. Power feels a little down, I need to do a compression check. The oil had visible dust contamination on the last change.

On September 11, after Honda makes their announcement, I will decide whether it gets a simple rebuild or gets a bunch of goodies in the engine....