Kenny G wrote on 12/10/16 at 13:44:22:Buckeye wrote: "The more pleats means more filter surface area as the paper is larger thus folded more to fit into the same space".
The only way that you can prove that point is to take 2 filters apart that have a different number of pleats on each and measure the length.
I have done this, admittedly the filters are used filters, the lengths of the paper are almost identical.
The paper was about a thousandth and a half thicker on the filter with the least number of pleats.
I rest my case.
Kenny G
No matter how you do it, the number of pleats does mean more surface area
providing the depth of each pleat (as mentioned by someone above) is the same. This provides more surface area for the oil to flow through.
I assume your filters were different brands, and thus some of the difference. Also, you didn't mention how much "overlap" each had. Any overlap would reduce the surface area to less than what would be the surface area if the paper were "stretched" out flat.
There are two main issues with filters. A filter's micron rating - the smallest particle that can pass through it. When I worked as a purchasing agent for a nationally known plastics injection company (that had over 75 HUGE hydraulic machines in each facility) we used to order some filters with a 5, 10 or 15 micron rating. The smaller the number the more it filtered out. However smaller micron rating means less oil flow. Therefore, increasing the surface area of the filter material (like putting in pleats) allowed for oil flow and still filtered out down to the specified micron.
The other issue with filters is oil flow. If you filter the oil well, but starve the engine (or whatever) you will still not be sufficient. Therefore increasing surface area will accomplish this.
My guess is that the two filters you tested were differing brand with differing mfg. procedures. However the one with MORE pleats (assuming the depth of each pleat is the same) will provide more filtering surface!
Years ago, after the plastics company job, I did some research (most of the details I have forgotten) for the micron rating for the filter in my car. Most automotive related filters do not even specify micron. However, if my memory serves me correctly I think the standard auto filter was 15 micron. Going to a smaller micron might get more particles out, but could starve the engine's critical components, and going to a larger micron would not filter out enough of the contaminants.
Check it out!
I rest my case!