Pete, this is something I learned over the years. A lot of people, including some professional tuners, make the mistake of choosing their filter media based on it having the lowest restriction. Actually, it works best to pick the media that filters the best for the application and giving it the needed size to not cause restriction. Another thing I learned is to keep the filter as far away as possible from the carb intakes in a plenum. The pulsing flow near an intake can wiggle the dirt through the filter. Moving the element further back allows the intake flow to be more of a steady pull and this works better.
