Harley-Davidson; new OEM filter supplier - MAHLE

[ZeeOSix]

In the automotive filter world, the term "nominal efficiency" is usually understood to be 50% efficiency, and the term "absolute efficiency" is understood to be 98.7% (call it 99%) efficient. In other filtering worlds (water, air, food, etc filtration), the term "nominal" may mean a variety of things, depending on what the filter maker wants to define it as.

Seems the "nominal" (Beta 2 = 50%) rating was started in the early 1970s per this Machinery Lubrication article. EcoGard also shows what they use the terms for.

Harley would have to tell you what the actual efficiency vs particle size was to know if they are using the term "nominal" in the automotive accepted meaning. Or is it even as good at 50% @ 5u. In any respect, they are playing word games with their claimed efficiency rating.

https://www.machinerylubrication.com/Read/217/iso-contamination

https://www.ecogard.com/resources/articles/truth-about-oil-filter-micron-ratings

 

[twX]

Here's a post from 2018 with some used oil particle count tests done using one of the "5-micron" filters, a standard Harley filter, and two Mobil 1 filters.

The 5-micron filter had the highest particle counts. However, its poor performance for large particles probably means that it was leaking dirty oil past the filter element.

 

[DuckRyder]

Based on my experiences with particle counts i don't think they are very useful in this context as they are super dependent on technique of sample. I would think this would be extra true of a dry sump Harley that keeps about a quart of old oil in it if not scavenged.

Also, at least at the time @shanneba was active i do not think the Super Premium 5 filter was reccomnded for the Sportster. (for arguable reasons).