Originally Posted By: ZeeOSix
Originally Posted By: Joenpb
Originally Posted By: Roadkingnc
fl820 and fl500 will interchange I would rather have the 820 for the extra capacity and media
The FL820 has a 16 PSI bypass vs the Fl500S which has an 8 lb bypass.
In other words the FL500S is in bypass more often, especially on cold starts. The FL820 is a cheap filter, is it really worth a possible increase in engine wear?
Not necessarily ... the bypass setting can also be dependent on how restrictive the filter media is, or even how fast the filter is anticipated to clog up with debris.
In other words, the filter with the higher bypass setting may not flow as well and create more delta P across the element, and/or might clog easier/faster because of the design of the media itself, which would increase its flow resistance quicker. Another important factor is what the expected oil flow rate is in the engine it's specified for, and the recommended oil viscosity range for that engine. Many factors go into the design.
Therefore, the engineers might have set the bypass valve setting higher to prevent unnecessary bypass openings based on these kind of design factors.
My thought is the bypass is to protect the filter element from collapsing or tearing from pressure difference and has nothing to do with the application. I do think the 500 will be in bypass more vs the 820, maybe not so much on my 1.6l engine
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