OK I found out how to do this finally.  All u need to do is
find the radius of 2 and 3.5  which is 1 and 1.75

and go here

http://www.webcalc.net/calc/0041.php

I was soooooooooooo "cone"fused.  Thank god for calculators and google.

Boy I am "frustum"ated!  

the answer is

Surface Area of a Conical Frustum
Top Radius: 1
Bottom Radius: 1.75
Height: 4

Surface Area: 35.159728445746

ok a regular filter is 5.125 by 5.125 approx
which is 26.265625.

Wow that k& n is like almost 10 inches bigger.  It also flows faster and without the airbox restricting the regular airflow it gets air more directly.

i measured mine and it was 2.5 bottom 2in top and 2 in height.

Top Radius: 1
Bottom Radius: 1.25
Height: 2

Surface Area: 14.247185463789

but mine has no snorkel, no air box, and blah blah.

Also, maybe we should start a new topic in the Technical Corner for formulas and measures....never know when we might need to convert liters to gallons or millimeters to inches....such as:

...Pi x D = C
...Pi x R² = Area
...1 gallon = 3.78 liters
...1 MM = .03937"
...25.4 MM = 1"

After all, we know "frustumating" numbers can be at times.

AND did I forget to mention....

The K&N pod filter is a "Pleated Frustum".  We have been talking about a frustum shaped cone filter with a flat surface.  Pod filters are pleated which give a bigger surface for dirt to get trapped.

Mr 650 wrote on 12/31/69 at 16:00:10:


Where you been, Mr. 650?

Anyway, I was trying to point out that we weren't talking about a simple flat surface, and so I mentioned the pleats above....kinda after the fact in the whole discussion, but it needed to be added since the dimensions that we used were based on the radial/linear dimensions that were provided by the K&N link that is posted even further up...

But you are right, and your point is a valid addition to the discussion.  It all started over an idea that one filter had less surface area than the other, and therefore restricted flow more than the other.   Blah, blah, blah....

Anyway, I also made a slight error, in that I hadn't seen a stock filter in a while...but my thinking is corrected now that I went out to the garage and had a look. Indeed, the stock filter also has some ripples or pleats as well.  Just not as many as the K&N.

In truth, the guy (can't remember off the top) with the "stealth pod" filter hidden in the gutted airbox probably has a filter with a greater surface area than both the stock and my K&N put together.  However his has a bend in it and the stock snorkel too.

How 'bout that?  Sound reasonable?  Probably the best flowing intake in this forum isn't even on a Savage, and we know who that is...it is Clive and his Kaw with the velocity stack

Yeah The stack is best, but then they don't have as many dust storms over there ya know.  

I should have spec'ed the K&N replacement filter vs pod. I tossed the OEM filter, and stuck in the K&N.
I would like to know the total area, pleats & all, of the pod and the replacement K&Ns, like if the pleats were flattened out.
Does the wife's 650 use the K&N replacement?

Man I am Louisville again and the weather is perfect for riding back home. (where the bike is) Been parked too much this summer.

Hey I mentioned the air was a straight shot in the 1st message  

The air has short distance to travel and its a straighter shot.  

Also I didnt take in the fact that both pod and sock have caps on them which would reduce the K&N by 2*3.14
and mine by 2*3.14 surface area.  As far as the pleats are concerned the stock filters are all bunched up and not really open, if not blocking air flow really.  If you really wanted to know you could buy one, take it apart, and measure it.  I think both pod,sock, and drop in filter have pleats that are spaced further apart and work more effectively.
As far as I am concerned anything is better than a stock filter except maybe no filter at all

Ya know what's really funny in all this?  The volume of air through any part of the engine will only be equal to the smallest area...considering atmospheric pressures or whatever.

What I mean is that we can have a 10 foot square filter surface and it won't make any difference if there is a restriction of a smaller size somewhere else....Unless someone is putting a blower on there and has modified the exhaust pretty heavily.

Let me see....a 40 MM carb.  Hmmm...that equals a diameter of 1.575 inches or a radius of .787 inches at the carb intake.  Now if we do the math...and use Pi x R² to get the carb intake area....3.14 x .787² = 1.946 square inches for the carb opening area.....Hmmmm

We can have any filter we want....It doesn't matter  'cause the engine sucks what it needs and none of this conversation changes a thing

All the larger surface area does is to ensure that the filter doesn't slow the air down.  Any tests on filter drag?  Aside from that, the larger the filter, the more area to collect dirt, and I doubt that anything changes until the filter gets dirty.

Personally, this conversation has been a fun mental exercise, but we are riding Savages after all.  It don't matter

Ain't all this fun?  Here we are, a bunch of arm chair engineers trying to figure what setup is the best....

What Curz said, is what I meant...I suppose that we'd have to bench test the carb with different filter setups to find how they affect air flow through the carb...maybe even dirty them up with equal amounts of dust to figure when any of them begin to restrict the flow, too.  However, I'm guessing that Suzuki and K&N have done both of these things and figured an optimum configuration for both....and I imagine that K&N has designed the "universal" RC-1250 for airflow that is greater than the Savage needs anyway.  I bet the K&N would work on a VTX 1800 even.

Personally, I like the K&N filter because it is so simple, uncluttered and easy to clean.  On the other hand, those that choose otherwise merely have different reasons, like not wanting to make extensive modifications to the stock parts.