Can using a higher flow oil filter increase pressure at idle? And a more restrictive filter reduce it? If so, how? It's my understanding that when/if a pump is below the relief setting changes in pressure won't register? I'm trying to understand how it all works.
Can dif. oil filters change oil pressure?
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oil is sucked up into the oil pump through the pickup screen and tube, the first place the oil goes is through the oil filter. (for the most part) Theoretically the oil filter will not noticeably affect pressure. at extreme oil flow volumes (high RPM) you may see some drop in oil pressure - but this is generally only the case with race cars, boats, or other applications where sustained high RPMs are experienced.
there are relief valves built into most (if not all) oil filters that open up when the filter is clogged to ensure oil flow. there is also a high pressure relief valve built into some oil pumps to limit the pressure (its generally set way above 100psi; likely closer to 200)
there are relief valves built into most (if not all) oil filters that open up when the filter is clogged to ensure oil flow. there is also a high pressure relief valve built into some oil pumps to limit the pressure (its generally set way above 100psi; likely closer to 200)
Originally Posted By: Brian_Bowers
Can using a higher flow oil filter increase pressure at idle? And a more restrictive filter reduce it? If so, how? It's my understanding that when/if a pump is below the relief setting changes in pressure won't register? I'm trying to understand how it all works.
What you said in red text above is correct. Since the oil pump is a positive displacement pump, then ideally when the pump is not in pressure relief mode ALL of the oil coming out of the pump must go through the filter & engine flow circuits.
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
But, once the oil pump hits the pressure relief setting it means the oil pressure coming out of the pump is constant and can't rise any further (ideally, if the relief valve is working 100% effectively). Once the pump is in relief mode, then if a more restrictive filter is used you will see a drop in engine oil pressure as compared to using a less restrictive filter.
The best way to get a feeling if one filter is more restrictive then another would be to note you oil pressure at higher RPMs with cold(ish) oil. If the engine oil pressure drops some under these conditions while using filter A vs. filter B, then filter B is more restrictive to flow.
Can using a higher flow oil filter increase pressure at idle? And a more restrictive filter reduce it? If so, how? It's my understanding that when/if a pump is below the relief setting changes in pressure won't register? I'm trying to understand how it all works.
What you said in red text above is correct. Since the oil pump is a positive displacement pump, then ideally when the pump is not in pressure relief mode ALL of the oil coming out of the pump must go through the filter & engine flow circuits.
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
But, once the oil pump hits the pressure relief setting it means the oil pressure coming out of the pump is constant and can't rise any further (ideally, if the relief valve is working 100% effectively). Once the pump is in relief mode, then if a more restrictive filter is used you will see a drop in engine oil pressure as compared to using a less restrictive filter.
The best way to get a feeling if one filter is more restrictive then another would be to note you oil pressure at higher RPMs with cold(ish) oil. If the engine oil pressure drops some under these conditions while using filter A vs. filter B, then filter B is more restrictive to flow.
Originally Posted By: tomcat27
oil is sucked up into the oil pump through the pickup screen and tube, the first place the oil goes is through the oil filter.
Actually, the first place the oil goes to after being sucked out of the sump is the oil pump ... not the filter. The filter is between the oil pump outlet and the engine inlet.
Here's the basic order of the oil flow path:
Sump > pickup screen/tube > oil pump > pressure relief valve > oil filter > engine circuit > back to sump > repeat flow path.
Originally Posted By: tomcat27
there is also a high pressure relief valve built into some oil pumps to limit the pressure (its generally set way above 100psi; likely closer to 200)
All oil pumps on cars have a pressure relief valve ... and they are typically set to around 70-90 psi ... not way up at 200 psi.
oil is sucked up into the oil pump through the pickup screen and tube, the first place the oil goes is through the oil filter.
Actually, the first place the oil goes to after being sucked out of the sump is the oil pump ... not the filter. The filter is between the oil pump outlet and the engine inlet.
Here's the basic order of the oil flow path:
Sump > pickup screen/tube > oil pump > pressure relief valve > oil filter > engine circuit > back to sump > repeat flow path.
Originally Posted By: tomcat27
there is also a high pressure relief valve built into some oil pumps to limit the pressure (its generally set way above 100psi; likely closer to 200)
All oil pumps on cars have a pressure relief valve ... and they are typically set to around 70-90 psi ... not way up at 200 psi.
Originally Posted By: tomcat27
there are relief valves built into most (if not all) oil filters that open up when the filter is clogged to ensure oil flow. there is also a high pressure relief valve built into some oil pumps to limit the pressure (its generally set way above 100psi; likely closer to 200)
The pump's pressure regulator valve is set WAY lower than that in many engines. On my Jeep, it appears to be set at around 40-50 psi. On my old Mopars, stock was 40 PSI but I now run higher-pressure springs in the regulator valves (except in the flathead six) so that they open at about 70 psi. I know not all engines work the same, but on most American v8s the pump pressure relief valve is the regulating factor in the oil pressure. It opens all the time in normal operation at highway speed because the pump can deliver all the oil the engine really needs at little more than a fast idle. Building up the hundreds of PSI that the pump would produce without a relief valve wouldn't do anything except blow apart oil filters and overload oil pump drive gears.
there are relief valves built into most (if not all) oil filters that open up when the filter is clogged to ensure oil flow. there is also a high pressure relief valve built into some oil pumps to limit the pressure (its generally set way above 100psi; likely closer to 200)
The pump's pressure regulator valve is set WAY lower than that in many engines. On my Jeep, it appears to be set at around 40-50 psi. On my old Mopars, stock was 40 PSI but I now run higher-pressure springs in the regulator valves (except in the flathead six) so that they open at about 70 psi. I know not all engines work the same, but on most American v8s the pump pressure relief valve is the regulating factor in the oil pressure. It opens all the time in normal operation at highway speed because the pump can deliver all the oil the engine really needs at little more than a fast idle. Building up the hundreds of PSI that the pump would produce without a relief valve wouldn't do anything except blow apart oil filters and overload oil pump drive gears.
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Originally Posted By: SuperBusa
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
Try as I might... this won't click for me. If my car makes 40 psi at idle (800 rpms) at 210 degree oil temp why wouldn't a more restrictive filter reduce the pressure registered on the gauge?
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
Try as I might... this won't click for me. If my car makes 40 psi at idle (800 rpms) at 210 degree oil temp why wouldn't a more restrictive filter reduce the pressure registered on the gauge?
SuperBusa... can you read and jump in on my other thread... you have/had a Z06 too: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1524869#Post1524869
Originally Posted By: 440Magnum
I know not all engines work the same, but on most American v8s the pump pressure relief valve is the regulating factor in the oil pressure. It opens all the time in normal operation at highway speed because the pump can deliver all the oil the engine really needs at little more than a fast idle.
Well, what's in red above is not always true. When the oil is at full temp and very thin, the pump's pressure relief valve probably never opens on most cars. That's why your pressure gauge is way down at high PRM with hot oil vs. way up in pressure at high RPM with cold oil. When you rev your engine up high with cold oil the pressure gauge will go up to some valve and stay there ... meaning the pump is most likely in pressure relief mode. Then is you do the same RPM with fully hot oil, the pressure gauge will be at some lower value ... meaning the pump is out of relief mode. If the gauge read the same high value hot and cold at the same RPM, then it would be in pressure relief mode in both cases.
I know in my cars that the hot max oil pressure is always lower than the cold max oil pressure ... meaning the pump is never in relief mode when the oil is fully hot.
Again, it all depends on many factors - oil pump gpm vs. RPM curve, pump relief pressure, oil temp/viscosity and filter/engine flow resistance factor. That combination of factors will determine when the pump goes into relief mode or not.
I know not all engines work the same, but on most American v8s the pump pressure relief valve is the regulating factor in the oil pressure. It opens all the time in normal operation at highway speed because the pump can deliver all the oil the engine really needs at little more than a fast idle.
Well, what's in red above is not always true. When the oil is at full temp and very thin, the pump's pressure relief valve probably never opens on most cars. That's why your pressure gauge is way down at high PRM with hot oil vs. way up in pressure at high RPM with cold oil. When you rev your engine up high with cold oil the pressure gauge will go up to some valve and stay there ... meaning the pump is most likely in pressure relief mode. Then is you do the same RPM with fully hot oil, the pressure gauge will be at some lower value ... meaning the pump is out of relief mode. If the gauge read the same high value hot and cold at the same RPM, then it would be in pressure relief mode in both cases.
I know in my cars that the hot max oil pressure is always lower than the cold max oil pressure ... meaning the pump is never in relief mode when the oil is fully hot.
Again, it all depends on many factors - oil pump gpm vs. RPM curve, pump relief pressure, oil temp/viscosity and filter/engine flow resistance factor. That combination of factors will determine when the pump goes into relief mode or not.
Well my LS6 w/ the LS4 high volume pump w/ a 52psi relief idles at 37 hot, cruises at 60ish, and maxes out at 84 WOT. This is with mobil 1 5w30 and a M1 filter.
Evern since removign my oil cooler it seems to idle at a lower pressure but WOT higher... it's all very confusing.
Obviously my oil return circuit can't flow enough oil hence the oil pressure in the 80s when hot.
When super hot like on track 260+ my pressure was always right at 50 psi.
Evern since removign my oil cooler it seems to idle at a lower pressure but WOT higher... it's all very confusing.
Obviously my oil return circuit can't flow enough oil hence the oil pressure in the 80s when hot.
When super hot like on track 260+ my pressure was always right at 50 psi.
Originally Posted By: Brian_Bowers
Originally Posted By: SuperBusa
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
Try as I might... this won't click for me. If my car makes 40 psi at idle (800 rpms) at 210 degree oil temp why wouldn't a more restrictive filter reduce the pressure registered on the gauge?
Because even if you put a more restrictive oil filter on the car the same volume of oil is reaching and going through the engine. NOW ... if the oil pressure sensor was BEFORE the oil filter then you WOULD see a higher oil pressure there if you used a more restrictive filter. When the pump goes into relief mode, the pressure is constant at the max possible that could be supplied to the filter/engine flow path. If you have a fixed pressure and "unlimited" volume, then if you increase the flow resistance (ie, filter) then the pressure on the backside of the filter would have to be less, which means the INLET pressure to the engine would be less since filter outlet P = engine inlet P.
Here's and example.
Filter A is more restrictive than Filter B. Both have bypass valves set to 15 psi (so they will not be in bypass in the example below).
If the oil pump is in relief at say 80 psi with 5w-30 Mobil 1 at 200 deg F with Filter A installed, then engine oil press = 75 psi on the gauge.
If Filter B is installed and the same conditions are achieved as above, then engine oil press = 70 psi on the gauge.
This means Filter A had a 10 PSID under these conditions, and less restrictive Filter B had a 5 PSID. You could only see this difference in filter resistance IF the pump is in pressure relief, because the filter/engine circuit is going to flow less gpm @ 80 psi supply pressure with Filter A than is Filter B was used instead.
Now, let's do an example with the same Filter A and B above when the pump is NOT in relief mode.
When the oil pump is not in relief mode, then ALL the oil volume coming out of the pump MUST go through the filter/engine flow path.
Look at just the point of flow between the filter and engine ... where the engine pressure sensor is located. Again, the conditions are 5w-30 Mobil 1 at 200 deg F. Let’s say that the engine RPM is at 3000 and the oil pump is NOT in relief mode. Also, this particular oil pump puts out say 6 gpm at 3000 RPM.
Assume that Filter A has 8 PSID with 6 gpm of this oil, and Filter B has a 4 PSID. Also, in order to make 6 gpm go down the engine circuit it takes 70 psi – that would be the gauge pressure at the engine inlet (ie, filter outlet).
So, with the engine at 3000 PRM with this oil there is 6 gpm going through the filter & engine, and the pump is NOT in relief mode.
With Filter A the pump output pressure will be 70 + 8 = 78 psi.
With Filter B the pump output pressure will be 70 + 4 = 74 psi.
But the pump’s relief pressure is 80, so it’s not in relief ... BUT, what happened is that the pump’s output pressure increased due to the more restrictive Filter A. And the key here to note is that the engine’s oil pressure stayed the SAME at 70 psi.
The more restrictive filter just caused the pump’s outlet pressure to run closer to the relief pressure setting. If you ran a more restrictive filter you would never know t his unless you had a pressure sensor BEFORE the filter. Most cars have the oil pressure sensor after the filter (before engine), so they will never see the effect of a more restrictive filter unless the pump is in pressure relief mode.
Hope that makes sense. It’s kind of tricky to see, but once you do it’s easy to understand.
Originally Posted By: SuperBusa
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
Try as I might... this won't click for me. If my car makes 40 psi at idle (800 rpms) at 210 degree oil temp why wouldn't a more restrictive filter reduce the pressure registered on the gauge?
Because even if you put a more restrictive oil filter on the car the same volume of oil is reaching and going through the engine. NOW ... if the oil pressure sensor was BEFORE the oil filter then you WOULD see a higher oil pressure there if you used a more restrictive filter. When the pump goes into relief mode, the pressure is constant at the max possible that could be supplied to the filter/engine flow path. If you have a fixed pressure and "unlimited" volume, then if you increase the flow resistance (ie, filter) then the pressure on the backside of the filter would have to be less, which means the INLET pressure to the engine would be less since filter outlet P = engine inlet P.
Here's and example.
Filter A is more restrictive than Filter B. Both have bypass valves set to 15 psi (so they will not be in bypass in the example below).
If the oil pump is in relief at say 80 psi with 5w-30 Mobil 1 at 200 deg F with Filter A installed, then engine oil press = 75 psi on the gauge.
If Filter B is installed and the same conditions are achieved as above, then engine oil press = 70 psi on the gauge.
This means Filter A had a 10 PSID under these conditions, and less restrictive Filter B had a 5 PSID. You could only see this difference in filter resistance IF the pump is in pressure relief, because the filter/engine circuit is going to flow less gpm @ 80 psi supply pressure with Filter A than is Filter B was used instead.
Now, let's do an example with the same Filter A and B above when the pump is NOT in relief mode.
When the oil pump is not in relief mode, then ALL the oil volume coming out of the pump MUST go through the filter/engine flow path.
Look at just the point of flow between the filter and engine ... where the engine pressure sensor is located. Again, the conditions are 5w-30 Mobil 1 at 200 deg F. Let’s say that the engine RPM is at 3000 and the oil pump is NOT in relief mode. Also, this particular oil pump puts out say 6 gpm at 3000 RPM.
Assume that Filter A has 8 PSID with 6 gpm of this oil, and Filter B has a 4 PSID. Also, in order to make 6 gpm go down the engine circuit it takes 70 psi – that would be the gauge pressure at the engine inlet (ie, filter outlet).
So, with the engine at 3000 PRM with this oil there is 6 gpm going through the filter & engine, and the pump is NOT in relief mode.
With Filter A the pump output pressure will be 70 + 8 = 78 psi.
With Filter B the pump output pressure will be 70 + 4 = 74 psi.
But the pump’s relief pressure is 80, so it’s not in relief ... BUT, what happened is that the pump’s output pressure increased due to the more restrictive Filter A. And the key here to note is that the engine’s oil pressure stayed the SAME at 70 psi.
The more restrictive filter just caused the pump’s outlet pressure to run closer to the relief pressure setting. If you ran a more restrictive filter you would never know t his unless you had a pressure sensor BEFORE the filter. Most cars have the oil pressure sensor after the filter (before engine), so they will never see the effect of a more restrictive filter unless the pump is in pressure relief mode.
Hope that makes sense. It’s kind of tricky to see, but once you do it’s easy to understand.
Originally Posted By: Brian_Bowers
Well my LS6 w/ the LS4 high volume pump w/ a 52psi relief idles at 37 hot, cruises at 60ish, and maxes out at 84 WOT. This is with mobil 1 5w30 and a M1 filter.
If the high volume oil pump has a relief setting of 52 psi, and you see 84 psi @ WOT on your oil pressure gauge, then it means the relief valve on the pump is not 100 efficient and can’t dump all the excess pump flow volume back to the sump at high RPM. That’s typical with most HV pumps, and one reason their relief setting is lower than one would think, so they (the designers) can take the inefficient relief valve into consideration for high RPM conditions.
Originally Posted By: Brian_Bowers
Ever since removing my oil cooler it seems to idle at a lower pressure but WOT higher... it's all very confusing.
By removing the oil cooler you have changed the flow resistance of the engine’s circuit (I’d consider the oil cooler part of the engine flow circuit). You have made the flow circuit a little less restrictive, so at idle @ 800 RPM when the pump is putting out a constant volume of oil, the pressure will decrease because the resistance to flow is now less. In your case, the oil cooler is most likey a parallel flow circuit to the engine, and it may it's oil supply someplace between the filter and engine, thereby causing the pressure gauge to see the effect of it's removal.
At high RPM, this new HV pump probably has aN actual "running" relief pressure that is higher than your OEM pump had. Even though the new HV pump is set to 52 psi, it can put out much more then that because its releif vavle can’t shunt all the excess volume back to the sump. If your engine was more free flowing, then the pump would regulate closer to the 52 psi setting it has.
You’ve changed too many things in the oil pumping system to pin it down to one thing ... it’s a combo of many things that have made the system perform like it does with the new setup. It’s just not the oil filter (that's a small factor here) ... but the new HV pump and removal of the oil cooler have made the largest factors in the new system pressure characteristics you’re seeing.
Originally Posted By: Brian_Bowers
Obviously my oil return circuit can't flow enough oil hence the oil pressure in the 80s when hot.
Yep ... as I described above. I think you’re referring to the relief valve circuit here.
Originally Posted By: Brian_Bowers
When super hot like on track 260+ my pressure was always right at 50 psi.
Meaning the pump is not in relief mode because the oil is too thin to produce much pressure for the given flow resistance its being forced through, even with the higher volume flow rates of the HV pump.
Originally Posted By: Brian_Bowers
Removing the oil cooler has somewhat changed the overall resistance of the flow system.
Yep ... like mentioned above.
Well my LS6 w/ the LS4 high volume pump w/ a 52psi relief idles at 37 hot, cruises at 60ish, and maxes out at 84 WOT. This is with mobil 1 5w30 and a M1 filter.
If the high volume oil pump has a relief setting of 52 psi, and you see 84 psi @ WOT on your oil pressure gauge, then it means the relief valve on the pump is not 100 efficient and can’t dump all the excess pump flow volume back to the sump at high RPM. That’s typical with most HV pumps, and one reason their relief setting is lower than one would think, so they (the designers) can take the inefficient relief valve into consideration for high RPM conditions.
Originally Posted By: Brian_Bowers
Ever since removing my oil cooler it seems to idle at a lower pressure but WOT higher... it's all very confusing.
By removing the oil cooler you have changed the flow resistance of the engine’s circuit (I’d consider the oil cooler part of the engine flow circuit). You have made the flow circuit a little less restrictive, so at idle @ 800 RPM when the pump is putting out a constant volume of oil, the pressure will decrease because the resistance to flow is now less. In your case, the oil cooler is most likey a parallel flow circuit to the engine, and it may it's oil supply someplace between the filter and engine, thereby causing the pressure gauge to see the effect of it's removal.
At high RPM, this new HV pump probably has aN actual "running" relief pressure that is higher than your OEM pump had. Even though the new HV pump is set to 52 psi, it can put out much more then that because its releif vavle can’t shunt all the excess volume back to the sump. If your engine was more free flowing, then the pump would regulate closer to the 52 psi setting it has.
You’ve changed too many things in the oil pumping system to pin it down to one thing ... it’s a combo of many things that have made the system perform like it does with the new setup. It’s just not the oil filter (that's a small factor here) ... but the new HV pump and removal of the oil cooler have made the largest factors in the new system pressure characteristics you’re seeing.
Originally Posted By: Brian_Bowers
Obviously my oil return circuit can't flow enough oil hence the oil pressure in the 80s when hot.
Yep ... as I described above. I think you’re referring to the relief valve circuit here.
Originally Posted By: Brian_Bowers
When super hot like on track 260+ my pressure was always right at 50 psi.
Meaning the pump is not in relief mode because the oil is too thin to produce much pressure for the given flow resistance its being forced through, even with the higher volume flow rates of the HV pump.
Originally Posted By: Brian_Bowers
Removing the oil cooler has somewhat changed the overall resistance of the flow system.
Yep ... like mentioned above.
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Originally Posted By: Brian_Bowers
Originally Posted By: SuperBusa
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
Try as I might... this won't click for me. If my car makes 40 psi at idle (800 rpms) at 210 degree oil temp why wouldn't a more restrictive filter reduce the pressure registered on the gauge?
It can't unless the pump is in relief or if it (the pump) is of low efficiency. It can elevate the pressure if it is read on the pump side of the filter ..but not lower it on the engine side of the filter. If the engine is getting the same identical flow rate (the pump isn't in relief) ..then the engine should be dropping/producing the same pressure reading (at the same visc ..flow rate ..etc..etc.).
When someone is reporting a pressure reduction with a filter change, they either have a worn oil pump ..one that is inherently of lower efficiency, or their relief valve is leaking or the spring is worn out.
Some oil pumps may be of lower low speed efficiency for some design advantage in the upper rpm area (for all I know).
Originally Posted By: SuperBusa
If you put a more restrictive oil filter on the car, and if anytime the pump is not in relief mode, then the output pressure of the pump will be slightly higher to overcome the added resistance of the more resistive filter – but the same positive displacement of oil volume is still going through the filter/engine because the relief valve is still closed. Even though the pump is producing more pressure to move the same volume of oil through a more restrictive path, if the pump’s output pressure is still below the relief setting then you will never see any difference in engine oil pressure – ie, the pressure between the filter and engine where most oil pressure gauge sensors are located.
Try as I might... this won't click for me. If my car makes 40 psi at idle (800 rpms) at 210 degree oil temp why wouldn't a more restrictive filter reduce the pressure registered on the gauge?
It can't unless the pump is in relief or if it (the pump) is of low efficiency. It can elevate the pressure if it is read on the pump side of the filter ..but not lower it on the engine side of the filter. If the engine is getting the same identical flow rate (the pump isn't in relief) ..then the engine should be dropping/producing the same pressure reading (at the same visc ..flow rate ..etc..etc.).
When someone is reporting a pressure reduction with a filter change, they either have a worn oil pump ..one that is inherently of lower efficiency, or their relief valve is leaking or the spring is worn out.
Some oil pumps may be of lower low speed efficiency for some design advantage in the upper rpm area (for all I know).
Originally Posted By: SuperBusa
Originally Posted By: Brian_Bowers
Ever since removing my oil cooler it seems to idle at a lower pressure but WOT higher... it's all very confusing.
By removing the oil cooler you have changed the flow resistance of the engine’s circuit (I’d consider the oil cooler part of the engine flow circuit). You have made the flow circuit a little less restrictive, so at idle @ 800 RPM when the pump is putting out a constant volume of oil, the pressure will decrease because the resistance to flow is now less. In your case, the oil cooler is most likey a parallel flow circuit to the engine, and it may get it's oil supply someplace between the filter and engine, thereby causing the pressure gauge to see the effect of it's removal.
After thinking about this some more, I have this alternative viewpoint below. What I said above would be true if the oil cooler was truely in series with the engine flow circuit.
Were ever it is connected, an oil cooler will most likely have a parallel flow circuit to the engine (all the ones I've seen). This means that it takes part of the total volume of oil that enters the engine circuit after the oil flow goes through the oil filter. If that's the case, then removing it would cause that same fixed flow volume (when pump is NOT in relief) to go through a more restictive circuit and should cause the oil pressure to increase, not decrease.
Originally Posted By: Brian_Bowers
Ever since removing my oil cooler it seems to idle at a lower pressure but WOT higher... it's all very confusing.
By removing the oil cooler you have changed the flow resistance of the engine’s circuit (I’d consider the oil cooler part of the engine flow circuit). You have made the flow circuit a little less restrictive, so at idle @ 800 RPM when the pump is putting out a constant volume of oil, the pressure will decrease because the resistance to flow is now less. In your case, the oil cooler is most likey a parallel flow circuit to the engine, and it may get it's oil supply someplace between the filter and engine, thereby causing the pressure gauge to see the effect of it's removal.
After thinking about this some more, I have this alternative viewpoint below. What I said above would be true if the oil cooler was truely in series with the engine flow circuit.
Were ever it is connected, an oil cooler will most likely have a parallel flow circuit to the engine (all the ones I've seen). This means that it takes part of the total volume of oil that enters the engine circuit after the oil flow goes through the oil filter. If that's the case, then removing it would cause that same fixed flow volume (when pump is NOT in relief) to go through a more restictive circuit and should cause the oil pressure to increase, not decrease.
Well... here's the proof... it was the oil filter. I must have damaged the K&N internally when I hit the concrete.
Here's the oil pressure and temp when I got home from work today. It was moving from 39 to 40 and back again every few seconds. This is with a brand new Mobil 1 filter installed last weekend.
Oil temp is 207
Brand new K&N and some 5w30 to prime the filter
After I did some yard work I swapped the filter and went for a drive to get the car good and hot. Here's the result:
Oil pressure was going back and foth from 49-50 psi... would not drop any lower than 49.
Oil temp was 208
So... as you can see... swapping from the M1 back to the K&N resulted in a 10 PSI gain at idle. So in my setup the oil filter clearly does matter and the K&N clearly has a different media than the M1 eventhough the M1 is also made by Champion Labs and looks the same when cut apart. The hot cruise and WOT presures were the same because in these cases the oil pump was in relief.
Here's the oil pressure and temp when I got home from work today. It was moving from 39 to 40 and back again every few seconds. This is with a brand new Mobil 1 filter installed last weekend.
Oil temp is 207
Brand new K&N and some 5w30 to prime the filter
After I did some yard work I swapped the filter and went for a drive to get the car good and hot. Here's the result:
Oil pressure was going back and foth from 49-50 psi... would not drop any lower than 49.
Oil temp was 208
So... as you can see... swapping from the M1 back to the K&N resulted in a 10 PSI gain at idle. So in my setup the oil filter clearly does matter and the K&N clearly has a different media than the M1 eventhough the M1 is also made by Champion Labs and looks the same when cut apart. The hot cruise and WOT presures were the same because in these cases the oil pump was in relief.
Originally Posted By: Brian_Bowers
So... as you can see... swapping from the M1 back to the K&N resulted in a 10 PSI gain at idle. So in my setup the oil filter clearly does matter and the K&N clearly has a different media than the M1 eventhough the M1 is also made by Champion Labs and looks the same when cut apart. The hot cruise and WOT presures were the same because in these cases the oil pump was in relief.
FINALLY! I've waited for the longest time on here for someone to start a thread such as this and show the oil pressure increase that K&N filters have shown on not just this vehicle,but many others as well,including my own vehicle.
In everyone's vehicle,whom I know personally,they've all gained 9-10psi in oil pressure using the K&N oil filter. Just another reason why I run K&N oil filters
So... as you can see... swapping from the M1 back to the K&N resulted in a 10 PSI gain at idle. So in my setup the oil filter clearly does matter and the K&N clearly has a different media than the M1 eventhough the M1 is also made by Champion Labs and looks the same when cut apart. The hot cruise and WOT presures were the same because in these cases the oil pump was in relief.
FINALLY! I've waited for the longest time on here for someone to start a thread such as this and show the oil pressure increase that K&N filters have shown on not just this vehicle,but many others as well,including my own vehicle.
In everyone's vehicle,whom I know personally,they've all gained 9-10psi in oil pressure using the K&N oil filter. Just another reason why I run K&N oil filters
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This can only happen when the pump is in relief or is of lower efficiency. When the pump isn't in relief ..there's no alteration to flow ..hence, especially where the LS2 sensor is, there is no alteration of pressure.
It can't happen any other way. Now if you have a sender/sensor above the filter (pump side) then you can an increase in pressure ..and as long as that pressure is below the relief setting ..no flow is lost.
Once the relief is open ..any and all restrictions ..bends ..radiuses ..whatever ..will effect flow ..and pressure distributions.
It can't happen any other way. Now if you have a sender/sensor above the filter (pump side) then you can an increase in pressure ..and as long as that pressure is below the relief setting ..no flow is lost.
Once the relief is open ..any and all restrictions ..bends ..radiuses ..whatever ..will effect flow ..and pressure distributions.
Originally Posted By: DragRace
Originally Posted By: Brian_Bowers
So... as you can see... swapping from the M1 back to the K&N resulted in a 10 PSI gain at idle. So in my setup the oil filter clearly does matter and the K&N clearly has a different media than the M1 eventhough the M1 is also made by Champion Labs and looks the same when cut apart. The hot cruise and WOT presures were the same because in these cases the oil pump was in relief.
FINALLY! I've waited for the longest time on here for someone to start a thread such as this and show the oil pressure increase that K&N filters have shown on not just this vehicle,but many others as well,including my own vehicle.
In everyone's vehicle,whom I know personally,they've all gained 9-10psi in oil pressure using the K&N oil filter. Just another reason why I run K&N oil filters
FYI I only see a pressure increase at idle... at hot cruise and WOT they're the same.
Originally Posted By: Brian_Bowers
So... as you can see... swapping from the M1 back to the K&N resulted in a 10 PSI gain at idle. So in my setup the oil filter clearly does matter and the K&N clearly has a different media than the M1 eventhough the M1 is also made by Champion Labs and looks the same when cut apart. The hot cruise and WOT presures were the same because in these cases the oil pump was in relief.
FINALLY! I've waited for the longest time on here for someone to start a thread such as this and show the oil pressure increase that K&N filters have shown on not just this vehicle,but many others as well,including my own vehicle.
In everyone's vehicle,whom I know personally,they've all gained 9-10psi in oil pressure using the K&N oil filter. Just another reason why I run K&N oil filters
FYI I only see a pressure increase at idle... at hot cruise and WOT they're the same.
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Originally Posted By: Gary Allan
This can only happen when the pump is in relief or is of lower efficiency. When the pump isn't in relief ..there's no alteration to flow ..hence, especially where the LS2 sensor is, there is no alteration of pressure.
It can't happen any other way. Now if you have a sender/sensor above the filter (pump side) then you can an increase in pressure ..and as long as that pressure is below the relief setting ..no flow is lost.
Once the relief is open ..any and all restrictions ..bends ..radiuses ..whatever ..will effect flow ..and pressure distributions.
IF all of that is the case then why do I see no difference at hot cruise or WOT? The only place I see a pressure increase is hot idle.
This can only happen when the pump is in relief or is of lower efficiency. When the pump isn't in relief ..there's no alteration to flow ..hence, especially where the LS2 sensor is, there is no alteration of pressure.
It can't happen any other way. Now if you have a sender/sensor above the filter (pump side) then you can an increase in pressure ..and as long as that pressure is below the relief setting ..no flow is lost.
Once the relief is open ..any and all restrictions ..bends ..radiuses ..whatever ..will effect flow ..and pressure distributions.
IF all of that is the case then why do I see no difference at hot cruise or WOT? The only place I see a pressure increase is hot idle.
Originally Posted By: Gary Allan
This can only happen when the pump is in relief or is of lower efficiency. When the pump isn't in relief ..there's no alteration to flow ..hence, especially where the LS2 sensor is, there is no alteration of pressure.
Also, if this is true then why to engines loose oil pressure as they wear and bearing clearnances grow? I understand that when the pump is not in relief it flows a fixed amount of fluid per turn, but wouldn't forcing that fluid through a more restrictive path cause the pressure to fall at each pressure drop?
This can only happen when the pump is in relief or is of lower efficiency. When the pump isn't in relief ..there's no alteration to flow ..hence, especially where the LS2 sensor is, there is no alteration of pressure.
Also, if this is true then why to engines loose oil pressure as they wear and bearing clearnances grow? I understand that when the pump is not in relief it flows a fixed amount of fluid per turn, but wouldn't forcing that fluid through a more restrictive path cause the pressure to fall at each pressure drop?
Hold on... I think I may have just "gotten it". Are you guys saying that my oil pump is making enough pressure to always be in relief? That at idle the pump is putting out 52psi, but that by the time in goes down the oil galley, through the filter, and makes it to the presssure sensor it's dropped 12psi for the M1 filter and 2psi for the K&N?
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