Silly question about bypass filtering

[buck91]

Doesn't the factory filters operate this way anyhow whenever oil pressure is above the bypass valve setting? For example (and only example because this is two different vehicles), the oil pressure in our Oldsmobile is almost always over 35psi except when warm/hot idle in drive (dips into low teens). Now, I don't know if/what the bypass is on that car since it uses a cartridge filter, but take for example the Motorcraft filter for my old Mustang (FL-820S), didn't that have a bypass pressure in the teens?

I'm probably misunderstanding this, but?

 

[Pontual]

I think you are confusing spot engine oil pressure with differential pressure inside the oil filter housing. That's a common misunderstanding.

 

[CT8]

The bypass valve in the filter of in the oil filter mounting area. Bypass pressure is the pressure difference between the unfiltered oil side of the filter cartridge and the filtered side,P.S.I.D.= Pounds per square inch differential. Oil travels from the outside of the cartridge element through the element and exits on the inside of the cartridge,through center.

 

[widman]

Right, there is no relation ship. The bypass in the filter, or block in many cases (or both) are there to bypass the filtering of the oil if there is too much restriction in the filter to let the correct pressure to the engine parts.

Think of all the pressure coming out of the nozzle of the hose to wash your car. If you step on the middle of the hose, you don't get enough pressure to wash. If there was a bypass on that hose at that point, the water would go through it.

 

[CT8]

https://www.amsoil.com/products/bypassfilters/bypass_dia_600px.jpg This link is a basic how a bypass filter is plumbed in to the engine. Bypass type filters were used before full flow filters though not with "micronic" filtering.