Exactly how does a bypass valve work?

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Note bypass oil flow in this chart … which can be different than what a BPV in the filter does
(BPV = piece of plastic and cheap spring)



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Originally Posted by Baveux
OK 2 filters fit the oem requirement one have the BP valve set at 22 the oem at 8. They both use different filter media I would think ( Fram TG versus FL500S )

Am I going to get a better filtration with the higher BP setting since the OP will push oil through the media up to a higher press. before the bp valve open ?


A higher set bypass valve will mean less potential for a bypass event, but there's more to it than that. A filter's bypass valve setting is also based on how flow restrictive the filter is when new, and what the expected max delta-p across the filter will be in use and when it loads up with debris. And the max expected oiling system flow volume (like the flow chart posted above shows) and oil viscosity factors are all considered.

The filter bypass valve also protects the filter from potential damage from delta-p. If the bypass valve is set too high, and the media can't take that much delta-p, then the media or center tube could get damaged. Another negative of a bypass valve set too high is potentially less oil supply to the engine if the filter clogs enough to make the pump hit pressure relief before a highly set bypass valve opens up.

If you use a filter specified by the manufacturer for the vehicle then I wouldn't worry about the bypass setting. Just because one filter has a higher bypass setting doesn't mean it's better.
 
Originally Posted by ZeeOSix
Originally Posted by Baveux
OK 2 filters fit the oem requirement one have the BP valve set at 22 the oem at 8. They both use different filter media I would think ( Fram TG versus FL500S )

Am I going to get a better filtration with the higher BP setting since the OP will push oil through the media up to a higher press. before the bp valve open ?


A higher set bypass valve will mean less potential for a bypass event, but there's more to it than that. A filter's bypass valve setting is also based on how flow restrictive the filter is when new, and what the expected max delta-p across the filter will be in use and when it loads up with debris. And the max expected oiling system flow volume (like the flow chart posted above shows) and oil viscosity factors are all considered.

The filter bypass valve also protects the filter from potential damage from delta-p. If the bypass valve is set too high, and the media can't take that much delta-p, then the media or center tube could get damaged. Another negative of a bypass valve set too high is potentially less oil supply to the engine if the filter clogs enough to make the pump hit pressure relief before a highly set bypass valve opens up.

If you use a filter specified by the manufacturer for the vehicle then I wouldn't worry about the bypass setting. Just because one filter has a higher bypass setting doesn't mean it's better.


Crystal clear, thanks for the time taken I appreciate :)
 
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