If a by-pass valve opens at a certain delta, in theory, the engine never knows when the filter is by-passing or not, right? It's all the same to the engine, pressure that is. So is the by-pass setting in a given filter, say 12psid, set at that level to protect the element, and it really does not matter to the engine, within reason, what that setting is? The concern here is to keep that little paper cupcake from getting smashed or ripped form its end caps.
by-pass valve setting?
- Thread starter LarryL
- Start date
- Status
Then why are there so many by-pass pressure opening settings?
Why not just 1 setting fits all applications?
Why does Ford have one that opens up at 8psid and VW 35psid?
Why not just 1 setting fits all applications?
Why does Ford have one that opens up at 8psid and VW 35psid?
Brand new filter media..regardless of type or who puts it in their brand filter has about a 1 psid pressure drop.
So while the media certainly isn't the "same"..the net result pressure drop wise is similar.
And certainly when you consider a by-pass setting that opens at 8 psid versus a different one that opens at 35 psid.
So while the media certainly isn't the "same"..the net result pressure drop wise is similar.
And certainly when you consider a by-pass setting that opens at 8 psid versus a different one that opens at 35 psid.
Excellent explanation, LarryL!
I guess VW, for example, wants to force oil through the filter media either (a) more of the time or (b) they spec a media that requires more pressure to work properly...?
Am I getting it?
I guess VW, for example, wants to force oil through the filter media either (a) more of the time or (b) they spec a media that requires more pressure to work properly...?
Am I getting it?
- Joined
- Sep 28, 2002
- Messages
- 39,798
Well, how about both, Big Dave? VW/AUDI HAS to use a substantially reinforced media to withstand the potential for 30+ psid. They also spec extended drains and use high volume/high pressure pumps. They surely "match" the filter bypass settings, their loading requirements, and their oil pump relief settings in concert with each other to form their "package".
So they want comparable filtration (of whatever high or low degree it may be) for much longer than a like sized fitler with different media.
That is, a common FLIA (let's say a PureOne PL30001) would probably work just fine on a VW/AUDI application ...for a limited length of time. It cannot fullfill OEM spec in probably a couple of areas ...under OEM spec conditions ..but it probably could for some duration of use.
The bypass is there to protect the media from excessive pressure. Filters with like beta, loading, and flow spec's may have different bypass settings. This must be done, or so one would reason, due to different construction techniques (thicker or more resilient media/etc.). A WIX may only need a 8-12 bypass (as opposed to Purolator's 12-16) since it will not develop higher pressures over the same duration of the PureOne in like service. OR ..the Purolator needs that added psid to compete with the same loading capacity of the Wix at a finer level of filtration over the same duration. A lower setting would have it in bypass far sooner then the Wix (you can swap that around a few ways).
So they want comparable filtration (of whatever high or low degree it may be) for much longer than a like sized fitler with different media.
That is, a common FLIA (let's say a PureOne PL30001) would probably work just fine on a VW/AUDI application ...for a limited length of time. It cannot fullfill OEM spec in probably a couple of areas ...under OEM spec conditions ..but it probably could for some duration of use.
The bypass is there to protect the media from excessive pressure. Filters with like beta, loading, and flow spec's may have different bypass settings. This must be done, or so one would reason, due to different construction techniques (thicker or more resilient media/etc.). A WIX may only need a 8-12 bypass (as opposed to Purolator's 12-16) since it will not develop higher pressures over the same duration of the PureOne in like service. OR ..the Purolator needs that added psid to compete with the same loading capacity of the Wix at a finer level of filtration over the same duration. A lower setting would have it in bypass far sooner then the Wix (you can swap that around a few ways).
If a filter is working correctly, the engine can't see the bypass valve working. The engine should see oil pressure as if the filter is not there, other than the small drop, like Filter guy states. If it's in bypass or not, the engine gets about the same oil pressure and flow. The design of the filter is more about filter ability and being built robust enough to survive the change interval, heat and pressure and the junk it picks up. In fact, if the media was made up of someting like stainless steel, the bypass valve would be less important. The ss filter would flow enough to make a bypass only necessary for those that don't change the oil and filter often enough.
What's the oil pump output?
And do you think any media can't handle the flow?..
And do you think any media can't handle the flow?..
Stainless steel media is up to the job. We just don't know too much about them. These non metalic elements have been with us for a long time, like seventy five years or so, thanks to Purolator. Maybe it's time for a change. And, since we don't often look inside a used full flow filter, there may be more failures than we know about. Those elements look kind of fragile when you consider what is pumped through them. The fact that they work at all is pretty amazing.
- Joined
- Sep 28, 2002
- Messages
- 39,798
That is 100% correct. Assuming the oil pump's pressure relief isn't open ..the engine could care less whether you've got a plugged filter ..a pinhole opening, a gapping hole ..a magic portal ..whatever. It will see whatever it sees. It will generate a backpressure totally dependent on the volume being pumped at a given viscosity. The filter only adds upstream pressure. Unless the oil pump is in relief, there is (in reality) no such thing as a 'pressure drop'. There is a pressure elevation from the engine side of the oil filter to the oil pump. It shows the change in velocity of the oil (sorta like a river when it hits a rapids - the flow is the same, only the intermediate velocity changes - the mean velocity is the same) That's how it works.
I've given this some thought to over the past year or so and have arrived at the same conclusions: Filter bypass pressure shouldn't matter as long as the bypass is reasonably below the pumps bypass pressure. Does anyone disagree with this?
For some time I been wanting to put on a remote 2µm hydraulic filter on my Taurus. It's bypass is set to 30 psi, however the pressure switch will turn on at 15 psi to alert you that a filter change is needed or that you've exceeded 15psi, maybe like a cold start-up. (the switches can also be 20 or 25 psi). Anyway, does this seem reasonable to put a filter on that has the bypass set twice as high a stock?
For some time I been wanting to put on a remote 2µm hydraulic filter on my Taurus. It's bypass is set to 30 psi, however the pressure switch will turn on at 15 psi to alert you that a filter change is needed or that you've exceeded 15psi, maybe like a cold start-up. (the switches can also be 20 or 25 psi). Anyway, does this seem reasonable to put a filter on that has the bypass set twice as high a stock?
- Joined
- Sep 28, 2002
- Messages
- 39,798
I would say that you should first determine how closely matched your oil pump volume/pressure is in regard to its relief setting. For example, my 2.5 jeep engine peaks out at under 60 psi (around 50) ..while my pressure relief is 75. My Caravan, OTOH, goes straight up to 80 psi when cold ..and the relief is 82. My only real indicator of wheter the pump is in relief is by reading the downstream pressure (lower by a few more psi) So, the only time that the filter could add enough upstream pressure elevation to envoke the pressure relief (in the jeep) due to loading would be very near the threshold anyway (the filter would be in bypass in 5psid anyway). In my Caravan, however, it could lower my downstream pressure, due to flow reduction, as much as 30 psi
I think you'll be just fine ..especially with your warning light thingy ..but I think that you're going to load that filter fairly quickly. Maybe not
I'd be interested how long it lasts as a full flow filter.
I think you'll be just fine ..especially with your warning light thingy ..but I think that you're going to load that filter fairly quickly. Maybe not
Check out Baldwin filters on the net. They have an excellent filter cross reference guide for any application and it lists all specs. Like filter sizes, thread size, filter media, construction materials and bypass opening pressures. I've found it a great source for finding odd filters for welders, hydraulics etc.
Anyone have two oil PSI senders in their vehicle?
Anyone compare actual pre/post-filter oil pressures?
Is the oil pump relief a poppet or a spring loaded variable bleed?
Anyone measure pumpslip as the media flow reaches its limit, and compare it with filters with higher or lower PSI bypasses?
Anyone compare actual pre/post-filter oil pressures?
Is the oil pump relief a poppet or a spring loaded variable bleed?
Anyone measure pumpslip as the media flow reaches its limit, and compare it with filters with higher or lower PSI bypasses?
- Joined
- Sep 28, 2002
- Messages
- 39,798
I'll raise my hand for the first two. One is defective at the moment.
- Status
