How often are filters in bypass mode?

[Plawan]

Oil filters *almost never* go into bypass mode.

Go back and read the “Jim Allen posts” that DNewton posted

I read them a long time ago. Thanks

 

[oil pan 4]

Oil filters *almost never* go into bypass mode.

Go back and read the “Jim Allen posts” that DNewton posted

New oil filters almost never go into bypass, probably.

 

[ZeeOSix]

Lots of factors effect the dP level across a filter. Any filter could go in to bypass if an engine is started with really thick cold oil and revved pretty high before the oil warms up. Never going wild on the gas pedal until the oil warms up will help a lot to keep the filter out of bypass.

 

[oil pan 4]

Interesting. I was thinking about my LFX engine which is known to have high oil pressure, up to like 90psi, but the PF63 filter it uses has a BPV rated at 22psi. But I see you're point, its not the pressure in the system that counts, its the pressure across the filter.

Yes another way to reduce or eliminate filter bypassing is find a filter that runs a higher bypassing pressure, assuming the vehicles doesn't already have one already built into the filter head. But it appears most vehicles have a built in filter bypass so that idea is probably a bust.

 

[Drew7a]

So one can conclude the following. Oil filters go into by pass (number of times unknown). So what good does a high efficiency filter get, a single by-pass event circulates what ever PPMs of contaminants and whatever size particles are in the oil (does no matter if you have a 99.999% at 20 microns). Oils running longer OCIs will have more contaminants and will circulate more debris during a bypass event. Sounds like another data point for short OCIs.

Short OCI = cleaner oil = less contaminants circulated during by pass event.

 

[oil pan 4]

So one can conclude the following. Oil filters go into by pass (number of times unknown). So what good does a high efficiency filter get, a single by-pass event circulates what ever PPMs of contaminants and whatever size particles are in the oil (does no matter if you have a 99.999% at 20 microns). Oils running longer OCIs will have more contaminants and will circulate more debris during a bypass event. Sounds like another data point for short OCIs.

Short OCI = cleaner oil = less contaminants circulated during by pass event.

Yeah shorter oci, bigger filter, higher bypass psid, lower "w" numbered oil, lower efficiency filter, synthetic blend, fully synthetic or fiberglass media.
The highest flowing and highest efficiency for a given size are usually glass media filters at least in hydraulic filters.
Paper is the cheapest, can have good efficiency at the cost of flow, paper also holds the most dirt as when flow drops to zero large chunks slide down and go to the bottom of the filter canister.
Synthetic and synthetic blend media including glass appears to hold on the dirt chunks and this could be good or bad depending on the application.