flow vs. filtering ability (archive)

There are two factors that affect how well a cone filters flows (measured in cfm). One is the filtering material, the other is the design of the airflow path.

An ITG filter uses layers of foam, sprayed with an oil, to filter the air. A K&N filter is similar, but it uses cotton gauze, again coated with oil, to filter.

After the air passes through the filtering medium (either foam or cotton in this case), it has to transition into the intake pipe (let's say it's a 3" tube). A radiused entry will flow considerably more than an entry with a sharp edge (or corner if you will).

For arguements sake, let's take a cotton filter medium and use a radiused pipe transition, then a cotton filter and a stepped pipe transition. The radiused transition is going to flow more air. Do the same test with a foam filtering medium and you'll have the same results.

Now, let's ASSUME that the foam filter is better at trapping particles than the cotton filter, thus, the foam medium flows less (not considering the transition area here). But, the foam filter uses a radiused transition versus a stepped transition.

If the ratio of flow for the radius vs. stepped transition is greater than the ratio of flow for the foam vs. cotton medium, then the foam/radiused filter will outflow the cotton/stepped filter.

What I'm getting at is that the combination of a foam filter with a radiused entry will give greater filtering ability and outflow a comparable cotton filter with a stepped entry. This is the ITG vs. K&N story.

Nick

Follow Ups:

Perhaps even more important is total filter area //EricF 18:02 10/31/2000 (1)
- Good point. That also affects total flow (n/m) m3niko 18:24 10/31/2000 (0)
Re: flow vs. filtering ability Jlee 22:33 10/30/2000 (0)

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