Why would I go out of my to try to prove anything to a person whose only contribution is vague dismissal and denial, completely void of any technical data? If you're just going to pout when your only details, the activities and recommendations of GM engineers, proves to be contradictory to the point you are trying to make, the rest pretty much speaks for itself.
Larger Filters? Good or bad?
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Originally Posted By: SHOZ
When I go to a different filter I use one that has a lower bypass setting. 8-9 vs 18-20 lbs. I still don't know the ramifications of this.
Nothing good. It means that its easier/more likely for the filter to go into bypass and send un-filtered oil directly to the engine, especailly on a cold start when the oil is thick. Granted, more filter area *might* offset that, but you're talking more than a 2:1 pressure change here.
Now, its also possible that nothing bad will happen either. Oiling systems are pretty tolerant. But you're on the wrong side of a "maybe" if you pick a filter that lowers the bypass pressure. I'd far rather use a stock filter even if I feel like its undersized, assuming my only choice for a bigger filter is a lower bypass pressure.
My number one rule is to make sure the the bypass setting is the same if I run an oversized filter.
When I go to a different filter I use one that has a lower bypass setting. 8-9 vs 18-20 lbs. I still don't know the ramifications of this.
Nothing good. It means that its easier/more likely for the filter to go into bypass and send un-filtered oil directly to the engine, especailly on a cold start when the oil is thick. Granted, more filter area *might* offset that, but you're talking more than a 2:1 pressure change here.
Now, its also possible that nothing bad will happen either. Oiling systems are pretty tolerant. But you're on the wrong side of a "maybe" if you pick a filter that lowers the bypass pressure. I'd far rather use a stock filter even if I feel like its undersized, assuming my only choice for a bigger filter is a lower bypass pressure.
My number one rule is to make sure the the bypass setting is the same if I run an oversized filter.
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Originally Posted By: 440Magnum
Originally Posted By: SHOZ
When I go to a different filter I use one that has a lower bypass setting. 8-9 vs 18-20 lbs. I still don't know the ramifications of this.
Nothing good. It means that its easier/more likely for the filter to go into bypass and send un-filtered oil directly to the engine, especailly on a cold start when the oil is thick. Granted, more filter area *might* offset that, but you're talking more than a 2:1 pressure change here.
My number one rule is to make sure the the bypass setting is the same if I run an oversized filter.
But why would it be OK for some engines and bad for mine? It's a the common Hyundai spin on filter rated at 20 lbs and speced for 100s of different engines.
Originally Posted By: SHOZ
When I go to a different filter I use one that has a lower bypass setting. 8-9 vs 18-20 lbs. I still don't know the ramifications of this.
Nothing good. It means that its easier/more likely for the filter to go into bypass and send un-filtered oil directly to the engine, especailly on a cold start when the oil is thick. Granted, more filter area *might* offset that, but you're talking more than a 2:1 pressure change here.
My number one rule is to make sure the the bypass setting is the same if I run an oversized filter.
But why would it be OK for some engines and bad for mine? It's a the common Hyundai spin on filter rated at 20 lbs and speced for 100s of different engines.
Originally Posted By: SHOZ
Originally Posted By: 440Magnum
Originally Posted By: SHOZ
When I go to a different filter I use one that has a lower bypass setting. 8-9 vs 18-20 lbs. I still don't know the ramifications of this.
Nothing good. It means that its easier/more likely for the filter to go into bypass and send un-filtered oil directly to the engine, especailly on a cold start when the oil is thick. Granted, more filter area *might* offset that, but you're talking more than a 2:1 pressure change here.
My number one rule is to make sure the the bypass setting is the same if I run an oversized filter.
But why would it be OK for some engines and bad for mine? It's a the common Hyundai spin on filter rated at 20 lbs and speced for 100s of different engines.
Because your engine may have a much higher oil FLOW rate. Flow rate (gallons per minute) is what will put a filter into bypass, not the outlet pressure as seen on the oil pressure gauge. Bypass is caused by pressure differential across the filter media. Take two engines, both that run at 50 PSI oil pressure on the gauge, and therefore indicated at the filter outlet. Now assume both filters have the same bypass pressure If one has a flow rate twice that of the other, then its filter will go into bypass sooner than the lower flow rate engine's filter, because it will have a higher pressure at the inlet to the filter due to the higher flow through the media. You never see that inlet pressure on your oil pressure gauge. So the engine manufacturer of the one that has the higher flow rate may specify a higher bypass pressure in order to keep the filter from going into bypass all the time.
Originally Posted By: 440Magnum
Originally Posted By: SHOZ
When I go to a different filter I use one that has a lower bypass setting. 8-9 vs 18-20 lbs. I still don't know the ramifications of this.
Nothing good. It means that its easier/more likely for the filter to go into bypass and send un-filtered oil directly to the engine, especailly on a cold start when the oil is thick. Granted, more filter area *might* offset that, but you're talking more than a 2:1 pressure change here.
My number one rule is to make sure the the bypass setting is the same if I run an oversized filter.
But why would it be OK for some engines and bad for mine? It's a the common Hyundai spin on filter rated at 20 lbs and speced for 100s of different engines.
Because your engine may have a much higher oil FLOW rate. Flow rate (gallons per minute) is what will put a filter into bypass, not the outlet pressure as seen on the oil pressure gauge. Bypass is caused by pressure differential across the filter media. Take two engines, both that run at 50 PSI oil pressure on the gauge, and therefore indicated at the filter outlet. Now assume both filters have the same bypass pressure If one has a flow rate twice that of the other, then its filter will go into bypass sooner than the lower flow rate engine's filter, because it will have a higher pressure at the inlet to the filter due to the higher flow through the media. You never see that inlet pressure on your oil pressure gauge. So the engine manufacturer of the one that has the higher flow rate may specify a higher bypass pressure in order to keep the filter from going into bypass all the time.
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Yes I am aware of that but the oil filter with the high spec is the common filter used on 100s of engines. I can't believe that they all have high flow oil pumps.
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
Originally Posted By: DoubleWasp
Why would I go out of my to try to prove anything to a person whose only contribution is vague dismissal and denial, completely void of any technical data? If you're just going to pout when your only details, the activities and recommendations of GM engineers, proves to be contradictory to the point you are trying to make, the rest pretty much speaks for itself.
+1 yep, I know, its sad.
Why would I go out of my to try to prove anything to a person whose only contribution is vague dismissal and denial, completely void of any technical data? If you're just going to pout when your only details, the activities and recommendations of GM engineers, proves to be contradictory to the point you are trying to make, the rest pretty much speaks for itself.
+1 yep, I know, its sad.
Originally Posted By: DoubleWasp
Why would I go out of my to try to prove anything to a person whose only contribution is vague dismissal and denial, completely void of any technical data? If you're just going to pout when your only details, the activities and recommendations of GM engineers, proves to be contradictory to the point you are trying to make, the rest pretty much speaks for itself.
No pouting here. Looking for FACTS, don't see any. Your denial is amusing. You have no technical data. None. No one does. Just conjecture. Imagine whatever you want.
In case you didn't know and wanted to whine about it...
Why would I go out of my to try to prove anything to a person whose only contribution is vague dismissal and denial, completely void of any technical data? If you're just going to pout when your only details, the activities and recommendations of GM engineers, proves to be contradictory to the point you are trying to make, the rest pretty much speaks for itself.
No pouting here. Looking for FACTS, don't see any. Your denial is amusing. You have no technical data. None. No one does. Just conjecture. Imagine whatever you want.
In case you didn't know and wanted to whine about it...
Originally Posted By: CrawfishTails
+1 yep, I know, its sad.
Aw, how cute. We have a big oil filter clique.
Post the facts please, piling on DW's diatribe only adds to the amusement here. No GM engineer anywhere recommends a larger filter than the factory spec. Guess why?
I hear nothing new just the same old tired imaginations of guys trying to justify their decisions...
+1 yep, I know, its sad.
Aw, how cute. We have a big oil filter clique.
Post the facts please, piling on DW's diatribe only adds to the amusement here. No GM engineer anywhere recommends a larger filter than the factory spec. Guess why?
I hear nothing new just the same old tired imaginations of guys trying to justify their decisions...
Originally Posted By: SHOZ
Yes I am aware of that but the oil filter with the high spec is the common filter used on 100s of engines. I can't believe that they all have high flow oil pumps.
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
It could be. I'm just saying that for YOUR engine, you've picked a filter with a lower bypass pressure and are at risk of going into bypass more often. Maybe it won't actually happen, but like I said I think its a choice that puts you on the wrong side of the "maybe."
Yes I am aware of that but the oil filter with the high spec is the common filter used on 100s of engines. I can't believe that they all have high flow oil pumps.
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
It could be. I'm just saying that for YOUR engine, you've picked a filter with a lower bypass pressure and are at risk of going into bypass more often. Maybe it won't actually happen, but like I said I think its a choice that puts you on the wrong side of the "maybe."
Well I don't have much choice due to space restrictions.
I just think that the real issue would be going the other way, from a low psi bypass to a high psi bypass filter.
Never could understand why Hyundai would say that some aftermarket filters may cause a ticking sound at start up when their filter is usually a higher bypass psi spec.
I just think that the real issue would be going the other way, from a low psi bypass to a high psi bypass filter.
Never could understand why Hyundai would say that some aftermarket filters may cause a ticking sound at start up when their filter is usually a higher bypass psi spec.
Does anyone here know how much the pumping losses due to 'slip' are for a typical positive displacement automotive oil pump? I understand there may be negligible benefit to reducing differential pressure if we always assume the difference in slip is zero, or negligible, when we increase backpressure slightly... but I don't know that to be the case. Slip is known to increase when viscosity is decreased, and when differential pressure (difference between inlet pressure and outlet pressure) is increased. At least that is what I have read.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
Originally Posted By: danthaman1980
Does anyone here know how much the pumping losses due to 'slip' are for a typical positive displacement automotive oil pump? I understand there may be negligible benefit to reducing differential pressure if we always assume the difference in slip is zero, or negligible, when we increase backpressure slightly... but I don't know that to be the case. Slip is known to increase when viscosity is decreased, and when differential pressure (difference between inlet pressure and outlet pressure) is increased. At least that is what I have read.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
That's all a good thought, but keep in perspective that a typical engine oiling system is 15 times MORE restrictive than a typical oil filter. In other words, if Filter A was more restrictive than Filter B, it won't be by much and therefore the effect on the oil pump efficiency is basically zero.
Does anyone here know how much the pumping losses due to 'slip' are for a typical positive displacement automotive oil pump? I understand there may be negligible benefit to reducing differential pressure if we always assume the difference in slip is zero, or negligible, when we increase backpressure slightly... but I don't know that to be the case. Slip is known to increase when viscosity is decreased, and when differential pressure (difference between inlet pressure and outlet pressure) is increased. At least that is what I have read.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
That's all a good thought, but keep in perspective that a typical engine oiling system is 15 times MORE restrictive than a typical oil filter. In other words, if Filter A was more restrictive than Filter B, it won't be by much and therefore the effect on the oil pump efficiency is basically zero.
Originally Posted By: CrawfishTails
Originally Posted By: ZeeOSix
Yes, as the sole purpose of an ADBV is to keep the filter and oiling system galleries (including between the filter and oil pump) from draining back down through the oil pump to the sump.
A lot of people seem to think if your oil filter has the inlet to it on top, then an ADBV isn't needed since oil stays in the filter itself. If the oil filter is at the same level as the oil pump, then it'll stay. A lot I've seen hang down on the side of the sump, below the pump though.
As you elude to, it depends on the physical configuration of the oiling system and filter location. I think there's a possibility that not having an ADBV in the filter will cause the system to drain down in cases even when the filter is mounted vertical with base facing upwards.
Originally Posted By: CrawfishTails
On the oil filters that are mounted very high, like cartridge ones you change on the top of the engine, does the oil stay in the pick-up tube and galley? I can think of some German engines and also some U.S. cars like that.
Engines with cartridge filters have some kind of built-in ADBV system since cartridge filters obviously don't have an ADBV. So I would think the engine designer would ensure the oiling system doesn't drain down when the engine is shut off.
Originally Posted By: ZeeOSix
Yes, as the sole purpose of an ADBV is to keep the filter and oiling system galleries (including between the filter and oil pump) from draining back down through the oil pump to the sump.
A lot of people seem to think if your oil filter has the inlet to it on top, then an ADBV isn't needed since oil stays in the filter itself. If the oil filter is at the same level as the oil pump, then it'll stay. A lot I've seen hang down on the side of the sump, below the pump though.
As you elude to, it depends on the physical configuration of the oiling system and filter location. I think there's a possibility that not having an ADBV in the filter will cause the system to drain down in cases even when the filter is mounted vertical with base facing upwards.
Originally Posted By: CrawfishTails
On the oil filters that are mounted very high, like cartridge ones you change on the top of the engine, does the oil stay in the pick-up tube and galley? I can think of some German engines and also some U.S. cars like that.
Engines with cartridge filters have some kind of built-in ADBV system since cartridge filters obviously don't have an ADBV. So I would think the engine designer would ensure the oiling system doesn't drain down when the engine is shut off.
Originally Posted By: SHOZ
Yes I am aware of that but the oil filter with the high spec is the common filter used on 100s of engines. I can't believe that they all have high flow oil pumps.
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
Perhaps someone could define "high flow..." oil pumps ? Given the near identical nature of the lubrication system in virtually every new engine, does one engine oil pump really move dramatically more oil...? Or are we talking about a similar range, something like 6 - 8 gpm or similar. Does anyone have any actual numbers...
I own a Subaru, which is rumoured to have a high flow oil pump, and specs a 23 psi by-pass oil filter. But nothing I've seen confirms this with any data.
Yes I am aware of that but the oil filter with the high spec is the common filter used on 100s of engines. I can't believe that they all have high flow oil pumps.
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
Perhaps someone could define "high flow..." oil pumps ? Given the near identical nature of the lubrication system in virtually every new engine, does one engine oil pump really move dramatically more oil...? Or are we talking about a similar range, something like 6 - 8 gpm or similar. Does anyone have any actual numbers...
I own a Subaru, which is rumoured to have a high flow oil pump, and specs a 23 psi by-pass oil filter. But nothing I've seen confirms this with any data.
I use to have a Taurus SHO with the Yamaha v6 motor. They were suppose to have a high volume low pressure system. Don't really know the pressures they ran but the engines did suffer from rod bearing wear and then the oil pressure light would come on at hot idle at under 100k mile.
I have a Hyundai 2L turbo now and it will put out near 90 lbs at redline on hot 0w40 oil with 30 lbs at idle. This is the car that I switched filters on. Can't say as there has been any issue. Have yet to cut the Wix open though to compare the filter media to the OEM Hyundai filter.
I have a Hyundai 2L turbo now and it will put out near 90 lbs at redline on hot 0w40 oil with 30 lbs at idle. This is the car that I switched filters on. Can't say as there has been any issue. Have yet to cut the Wix open though to compare the filter media to the OEM Hyundai filter.
Originally Posted By: geeman789
Originally Posted By: SHOZ
Yes I am aware of that but the oil filter with the high spec is the common filter used on 100s of engines. I can't believe that they all have high flow oil pumps.
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
Perhaps someone could define "high flow..." oil pumps ? Given the near identical nature of the lubrication system in virtually every new engine, does one engine oil pump really move dramatically more oil...? Or are we talking about a similar range, something like 6 - 8 gpm or similar. Does anyone have any actual numbers...
I own a Subaru, which is rumoured to have a high flow oil pump, and specs a 23 psi by-pass oil filter. But nothing I've seen confirms this with any data.
Here is a thread to keep you busy for a few days:
https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1410171#Post1410171
Originally Posted By: SHOZ
Yes I am aware of that but the oil filter with the high spec is the common filter used on 100s of engines. I can't believe that they all have high flow oil pumps.
Quite a few Mazda, Kias and Hyundais use this filter. Could it be the filter is so restrictive that it needs the higher setting?
Perhaps someone could define "high flow..." oil pumps ? Given the near identical nature of the lubrication system in virtually every new engine, does one engine oil pump really move dramatically more oil...? Or are we talking about a similar range, something like 6 - 8 gpm or similar. Does anyone have any actual numbers...
I own a Subaru, which is rumoured to have a high flow oil pump, and specs a 23 psi by-pass oil filter. But nothing I've seen confirms this with any data.
Here is a thread to keep you busy for a few days:
https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1410171#Post1410171
Originally Posted By: danthaman1980
Does anyone here know how much the pumping losses due to 'slip' are for a typical positive displacement automotive oil pump? I understand there may be negligible benefit to reducing differential pressure if we always assume the difference in slip is zero, or negligible, when we increase backpressure slightly... but I don't know that to be the case. Slip is known to increase when viscosity is decreased, and when differential pressure (difference between inlet pressure and outlet pressure) is increased. At least that is what I have read.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
Well, you can't really treat the oil pump as "positive displacement" in too much of your thinking anyway, and the reason is the pressure relief valve at the output of the pump and the input to the filter. Once the relief valve opens, all "positive displacement" bets are off- the pump is now supplying a constant pressure to the filter input, and the excess oil beyond what is required to generate that pressure against the pump's output just dumps back into the pan. The pressure that the engine side of the filter sees will be the relief valve pressure minus any pressure differential across the media. When everything is normal, that's not an issue because the engine's internal clearances produce almost all the back-pressure, and the filter media produces almost none. But if the media starts to load up or pulls a "Fram Orange Can" and collapses into a wad around the center tube, then the engine can certainly starve for adequate oil pressure and flow.
Does anyone here know how much the pumping losses due to 'slip' are for a typical positive displacement automotive oil pump? I understand there may be negligible benefit to reducing differential pressure if we always assume the difference in slip is zero, or negligible, when we increase backpressure slightly... but I don't know that to be the case. Slip is known to increase when viscosity is decreased, and when differential pressure (difference between inlet pressure and outlet pressure) is increased. At least that is what I have read.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
Well, you can't really treat the oil pump as "positive displacement" in too much of your thinking anyway, and the reason is the pressure relief valve at the output of the pump and the input to the filter. Once the relief valve opens, all "positive displacement" bets are off- the pump is now supplying a constant pressure to the filter input, and the excess oil beyond what is required to generate that pressure against the pump's output just dumps back into the pan. The pressure that the engine side of the filter sees will be the relief valve pressure minus any pressure differential across the media. When everything is normal, that's not an issue because the engine's internal clearances produce almost all the back-pressure, and the filter media produces almost none. But if the media starts to load up or pulls a "Fram Orange Can" and collapses into a wad around the center tube, then the engine can certainly starve for adequate oil pressure and flow.
Originally Posted By: 440Magnum
Originally Posted By: danthaman1980
Does anyone here know how much the pumping losses due to 'slip' are for a typical positive displacement automotive oil pump? I understand there may be negligible benefit to reducing differential pressure if we always assume the difference in slip is zero, or negligible, when we increase backpressure slightly... but I don't know that to be the case. Slip is known to increase when viscosity is decreased, and when differential pressure (difference between inlet pressure and outlet pressure) is increased. At least that is what I have read.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
Well, you can't really treat the oil pump as "positive displacement" in too much of your thinking anyway, and the reason is the pressure relief valve at the output of the pump and the input to the filter. Once the relief valve opens, all "positive displacement" bets are off- the pump is now supplying a constant pressure to the filter input, and the excess oil beyond what is required to generate that pressure against the pump's output just dumps back into the pan. The pressure that the engine side of the filter sees will be the relief valve pressure minus any pressure differential across the media. When everything is normal, that's not an issue because the engine's internal clearances produce almost all the back-pressure, and the filter media produces almost none. But if the media starts to load up or pulls a "Fram Orange Can" and collapses into a wad around the center tube, then the engine can certainly starve for adequate oil pressure and flow.
I certainly understand your logic here, and in fact I was not figuring the pressure relief valve into my thinking. So in fact, when the pressure between the pump and filter media is below the pressure relief valve setting, the pump can be treated as 'positive displacement', minus any slip - so the volume of oil delivered through the filter per engine revolution will be fairly constant. But when relief valve pressure is exceeded, the pump will deliver the relief valve pressure to the filter - but in that case, the volume of oil flowing through the filter is difficult to calculate because some excess volume is being bled off through the pressure relief valve.
If that is the case, isn't that a positive argument for a larger/less restrictive filter? In that case, during the relief event, the inlet pressure would be fairly constant and a filter with less delta P across the media would flow more oil across the media during the relief event???
When everything is 'normal', the pump should deliver a fairly constant volume (per revolution) through the filter - minus pumping losses due to slip - but as has been stated, the filter is designed to be less restrictive than the oiling system. (I'm still not sure how to rationalize this, since there are multiple paths within the oiling system, and different parts of the oiling system will exhibit differences in relative restrictiveness. Said a different way, if you could increase the volume of oil going through the filter at a given RPM, the increase in delivery of oil to each component is not necessarily proportional - some will see more of an increase in flow since the restriction through that part of the system is lower.)
Anyway, one last thought - in your 'orange can' example, the bypass valve would be flowing some amount of oil, so the engine would not be completely starved of oil pressure... I guess whether or not the engine would starve for adequate pressure would be a function of how much oil can flow through the bypass. Does that sound right?
Originally Posted By: danthaman1980
Does anyone here know how much the pumping losses due to 'slip' are for a typical positive displacement automotive oil pump? I understand there may be negligible benefit to reducing differential pressure if we always assume the difference in slip is zero, or negligible, when we increase backpressure slightly... but I don't know that to be the case. Slip is known to increase when viscosity is decreased, and when differential pressure (difference between inlet pressure and outlet pressure) is increased. At least that is what I have read.
I guess my question is this: Can anyone demonstrate that using a less restrictive filter will not decrease the pumping losses due to the 'slip' effect within the pump? In my head, the slip effect would be minimized by minimizing differential pressure (i.e., minimizing restriction/backpressure on the outlet side of the pump).
Just a thought.
Well, you can't really treat the oil pump as "positive displacement" in too much of your thinking anyway, and the reason is the pressure relief valve at the output of the pump and the input to the filter. Once the relief valve opens, all "positive displacement" bets are off- the pump is now supplying a constant pressure to the filter input, and the excess oil beyond what is required to generate that pressure against the pump's output just dumps back into the pan. The pressure that the engine side of the filter sees will be the relief valve pressure minus any pressure differential across the media. When everything is normal, that's not an issue because the engine's internal clearances produce almost all the back-pressure, and the filter media produces almost none. But if the media starts to load up or pulls a "Fram Orange Can" and collapses into a wad around the center tube, then the engine can certainly starve for adequate oil pressure and flow.
I certainly understand your logic here, and in fact I was not figuring the pressure relief valve into my thinking. So in fact, when the pressure between the pump and filter media is below the pressure relief valve setting, the pump can be treated as 'positive displacement', minus any slip - so the volume of oil delivered through the filter per engine revolution will be fairly constant. But when relief valve pressure is exceeded, the pump will deliver the relief valve pressure to the filter - but in that case, the volume of oil flowing through the filter is difficult to calculate because some excess volume is being bled off through the pressure relief valve.
If that is the case, isn't that a positive argument for a larger/less restrictive filter? In that case, during the relief event, the inlet pressure would be fairly constant and a filter with less delta P across the media would flow more oil across the media during the relief event???
When everything is 'normal', the pump should deliver a fairly constant volume (per revolution) through the filter - minus pumping losses due to slip - but as has been stated, the filter is designed to be less restrictive than the oiling system. (I'm still not sure how to rationalize this, since there are multiple paths within the oiling system, and different parts of the oiling system will exhibit differences in relative restrictiveness. Said a different way, if you could increase the volume of oil going through the filter at a given RPM, the increase in delivery of oil to each component is not necessarily proportional - some will see more of an increase in flow since the restriction through that part of the system is lower.)
Anyway, one last thought - in your 'orange can' example, the bypass valve would be flowing some amount of oil, so the engine would not be completely starved of oil pressure... I guess whether or not the engine would starve for adequate pressure would be a function of how much oil can flow through the bypass. Does that sound right?
Originally Posted By: SteveSRT8
No pouting here. Looking for FACTS, don't see any.
So you can't read.
Quote:
Your denial is amusing. You have no technical data. None. No one does. Just conjecture. Imagine whatever you want.
A perfect description of yourself.
Quote:
In case you didn't know and wanted to whine about it...
I'm not whining. I was discussing tech, while you were [censored] about what I was writing. Don't make it out to be the other way around.
No pouting here. Looking for FACTS, don't see any.
So you can't read.
Quote:
Your denial is amusing. You have no technical data. None. No one does. Just conjecture. Imagine whatever you want.
A perfect description of yourself.
Quote:
In case you didn't know and wanted to whine about it...
I'm not whining. I was discussing tech, while you were [censored] about what I was writing. Don't make it out to be the other way around.
Originally Posted By: SteveSRT8
Aw, how cute. We have a big oil filter clique.
Post the facts please, piling on DW's diatribe only adds to the amusement here. No GM engineer anywhere recommends a larger filter than the factory spec. Guess why?
I hear nothing new just the same old tired imaginations of guys trying to justify their decisions...
My my! Your argument ad-hominem increases with each new post.
Reading comprehension is obviously not your strongest quality. I specifically stated that GM engineers spec oversize filters based on application for the same exact engine models. If increasing the filter size is truly as pointless as you claim, then why do your hallowed GM engineers spec different size filters for the same exact engine, with increasing sizes according to the usage of the vehicle? Why doesn't the smallest spec filter cut it for all uses across all vehicles?
Increasing filter size clearly does have a benefit if your own treasured GM engineers have engaged in this practice.
But now, I guess now that you've been confronted with the simple fact that even the OEMs engage in increasing filter sizes, you're going to backpedal onto a purely semantic argument that these oversize filters are all factory spec, and therefore not oversize.
Aw, how cute. We have a big oil filter clique.
Post the facts please, piling on DW's diatribe only adds to the amusement here. No GM engineer anywhere recommends a larger filter than the factory spec. Guess why?
I hear nothing new just the same old tired imaginations of guys trying to justify their decisions...
My my! Your argument ad-hominem increases with each new post.
Reading comprehension is obviously not your strongest quality. I specifically stated that GM engineers spec oversize filters based on application for the same exact engine models. If increasing the filter size is truly as pointless as you claim, then why do your hallowed GM engineers spec different size filters for the same exact engine, with increasing sizes according to the usage of the vehicle? Why doesn't the smallest spec filter cut it for all uses across all vehicles?
Increasing filter size clearly does have a benefit if your own treasured GM engineers have engaged in this practice.
But now, I guess now that you've been confronted with the simple fact that even the OEMs engage in increasing filter sizes, you're going to backpedal onto a purely semantic argument that these oversize filters are all factory spec, and therefore not oversize.
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