After many years of designing and testing racing oil systems and related components, we've collected a great deal of information to determine what's most important to oil filtration. Our conclusion was Total Filtration Time!

Many filter manufacturers stress the importance of filtering some of the smallest particles known to man out of your engine's oil. You've probably seen or heard them talk about "micron ratings" of 10 or less when talking about a filter's efficiency. (One micron is one-millionth of a meter and a "micron rating" of 10 means that the filter will remove particles as small as 10 millionths of a meter.)

Moroso engineers have determined, with the help of research performed by filtration technology experts, that particles smaller than 20 microns in diameter are not large enough to produce engine wear. Furthermore, Moroso engineers have also found that filters with extremely low micron ratings create an excessive pressure drop across the filter. They can be so restrictive that the filter by-pass valve can open. And with the by-pass valve open, NO FILTRATION occurs, and you have no way of knowing!

To maximize filter performance, Moroso Oil Filters have a rating of 27 microns, which produces a maximum initial restriction of only 2.5 psi when tested to SAE j806. The result is less pressure drop, more flow, less oil by-pass and maximum filtration performance that's so important in severe racing conditions.