We were on a road trip and in a small town when I decided to replace a dirty air filter. The only thing available was a Fram so I put it in. The next couple of tanks I noticed the mileage was down a bit so I started watching the filter-minder. Every stop I would find it pulled down about 1/2.
Got home and put in a Napa Gold (Wix) filter and the mileage came right back and the "minder" has not moved.
The Fram seemed to keep everything clean but was restrictive. I counted the pleats in the Fram (I can't remeber the exact amount) and it was around 68 or some such thing.
Counted the pleats in the Napa Gold and it was about 46 or so.
Very noticeable difference in the spacing between the pleats.

 

More pleats implies more surface area, which would indicate less pressure drop across the filter. However, the filter minder tells the opposite story: Too much pressure drop. This would seem to indicate that the filter media itself is too restrictive even with the additional pleats.

Good to know...Thanks!

Tony