Long ago, as a result of air filter testing we did in school (B.S. Aero Engrg and for A&P certificate) I always favored stock (or at least pleated paper) airfilters changed regularly.  Bought on sale when possible, but still pleated paper,... not oiled foam (Uni) or oiled gauze (K&N).

Here are some more recent tests.  They are in agreement with the tests we did in the engine labs so long ago.  A few basic points:
-- Quality pleated paper filters usually flow about as good as you can get.  In the tests below, when the K&N did flow better it was only a tiny bit better,... very tiny,... so tiny it was within the marging of testing error.
-- Quality pleated filters trapped more particles.  Dust, dirt, etc.  Quality pleated filters send cleaner air to the engine.
-- Occasionally the oil used on foam or gauze filters can contaminate sensors inside the intake or exhaust systems.  Not much of a factor for a Savage, though, eh?


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

http://www.jackphelps.com/frontier/dynoknfilter.htm

http://www.bmwe34.net/E34main/Upgrade/Air_filter.htm

http://www.bobistheoilguy.com/airfilter/airtest1.htm

Super Thumper wrote on 12/17/12 at 07:32:30:



Valid reasons.  One thing I got out of all those research projects was that while there were differences, the differences were never very much in flow or filtration.

For the same reasons as yours, there are guys that put a velocity stack on the carb and use a simple convex screen over the mouth of the opening.  Keeps the bugs out, eh?

Quote:


Ummmm maybe because it does? Is this guy serious? The more air you can get into the engine, the more power you can extract from it. This is basic knowledge. And clearly this guy has never noticed just how much air an engine can suck in while he rants in his ALL CAPS like a bloody teenager. This test sure looks like it means something but he's only showing us figures for an engine drawing 350CFM. What good is that? A naturally aspirated 350sbc draws over 500CFM at 5,000 rpm. Add a supercharger or turbo to that and those figures double or triple. No paper filter is ever going to allow enough air in and I know this from personal experience. My old turbo-charged Eclipse gained over 1sec at the drag strip from simply removing the stock air-box and putting a large K&N cone filter on.

But as I've said before in another post - the very small particulates that a good gauze filter may pass are still far too small to be harmful to your engine.

Let this guy play with his paper filters because he clearly doesn't care about performance - he cares about making sure his stupid O2 sensor doesn't get clogged. Boo hoo.

I,am running a K&N RC-2340 this is the only K&N air filter I've  found that would clear ever thing from stock air box with snorkel removed, to a lowered seat pan and tank & seat mounts bracket  clearance  without cutting or grinding  anything only thing is your going to have to rejet.
I've got a 2006 thats bobbed out  335 pounds  and get alot of looks with the air box removed  because  the openness  of the frame now gives it custom frame look plus makes the engine look hugh witch it is large single 650

super thumper is this the look ??? check it out keep's up with my buds  shovel head for a while. market place 2006 s40 bobber saline mi. if i can help you out pm me not to good on computer but will try to help you out .I   grew up in the late 60.s and rember old twins and singels BSA wamted to put BSA tank badges on could be done with after market plastic and a little bit of heat . If you take the chrome head cover off lookes like a 500 bsa gold star when I go to bike week i summer the old timers say nice gold star then they say nice try shifter on the wroung side  have a lot fun with this bike and got a 883 out the hole purrty good ha ha 100 + lbs lighter good luck with your procheck

Some topics in here hint that attaching cone directly to carb is not the best solution, due the airflows turbulance or whatever  
But still many of us seem to have this method... I am not looking for the ultimate powerhouse, so is there any issues why not to go for directly one of these K&N models RC 1250, 2880 or 2340. All these are out there, but what is the difference?

It looks like KN RC-2880. Atleast it has 57mm diameter in intake (2.25 in). I like the way the vapor hose is connected to this small place.

How tight are the cones? I found interesting Simota filter, but they only have 55mm diameter max. Could it fit to 57mm?