FLA1 Motorcraft filter & 100 psi oil pressure

Gary Allan · Aug 21, 2006

quote:

Here is what is wrong with your theory. When you increase the amount of oil "shunted to the relief" you state there is reduced flow--presumably because more oil is now flowing out the relief.

Yes, you do get less then 100% of the pumped volume in flow. There's no two ways about this. You're incorrectly reading too much into that ONE element in the total assertion. It's because there is a parallel path that the flow dynamics change radically from a simple series "no choice" circuit to a parallel circuit where the shunt is of unknown impedence to flow.

quote:

the engine will see the exact same flow,

Prove this to me? That is, you've offered nothing in any descriptive fashion that this is some type of mandate. I've already, repeatedly, said that the filter bypass valve limits the amount of oil that the relief can shunt since it limits the amount of TOTAL resistance that the filter can present to flow. That is the filter/engine leg of the circuit can only drop 10 psi (in our expample)over the filter ...hence (backtracking throught the immutable formulas for pressure dedicated flow) the flow can only be reduced X amount.

I think you're just agreeing with me in slightly altered terms.

I'll continue to qualify and clarify if needed

Gary Allan · Aug 21, 2006

What you're missing is the "manipulations" that the bypass introduces to the flow.

When there is no relief ..there will be little, if any, PSID. I don't care if it's 20w-50 or 20w-70. If that relief doesn't open ..the engine will still produce an incredible amount of pressure ..and the filter will fall in line in proportion.

QED - done.

When the relief is open, which can and will occur from time to time .. in cold conditions ..or flatshifting @ 8000 rpm, then there is a balance between the impedence of the relief and the impedence of the filter ..in a reciprocol manner. More flow shunted ...higher PSID ..less flow shunted .(returning to a more normalized circuit) ...less PSID. If unencumbered (no bypass valve), there is NO LIMIT to the amount of shunted fluid since there is no limit to the impedence that the filter can attain (short of collapsing). The bypass valve antennuates this impedence ..hence antennuatates the shunted flow.

another Todd · Aug 21, 2006

Will this do?

http://www.fram.com/pdf/ThreeVital.pdf

Gary Allan · Aug 21, 2006

What does that say that I haven't said? It surely doesn't discuss the internal dynamics of flow during those conditions.

I'll say it again for clarity. The bypass valve is to protect the engine from starvation. The bypass valve setting is to protect the media.

btw- I had a 10k used PUREONE filter ..and it had very little PSID except when cold.

lookie

and here t@@!

another Todd · Aug 21, 2006

When there is no relief ..there will be little, if any, PSID. I don't care if it's 20w-50 or 20w-70. If that relief doesn't open ..the engine will still produce an incredible amount of pressure ..and the filter will fall in line in proportion.

Are you talking pump relief or bypass relief? I assume pump relief. I'll say it again, Pump relief has no effect on filter bypass operation. When the is no pump relief ALL the oil goes through the oiling system, most of the time all of it will be filtered, EXCEPT when filter loading or thick oil causes an undue restriction at the filter media,(10 psi or more in our examples) then it's a free ride through the bypass. Even when the filter is in bypass, some oil is going through the filter unless it is plugged.

another Todd · Aug 21, 2006

Gary says: When there is no relief ..there will be little, if any, PSID. I don't care if it's 20w-50 or 20w-70. If that relief doesn't open ..the engine will still produce an incredible amount of pressure ..and the filter will fall in line in proportion.

Fram says in its last sentence about the filter byass valve that thick oil CAN cause the filter to bypass. In complete disagreement with what you stated.

another Todd · Aug 21, 2006

And another thing, in your engine 82psi max pressure, your engine sees 82psi and the same flow whether you are flowing 1gpm or 3 gpm out your relief valve. If it didn't the relief valve would close because it is based on pressure! If your engine saw reduced flow when the pumps relief valve opened, that would equate to reduced pressure (higher flow creates higher pressure)(lower flow creates lower pressure)and your pumps relief valve would close. When you rev up your engine to achieve 82psi oil pressure, lets just say 3000rpm, now rev the engine to 4000rpm, does your oil pressure drop? It would if you had reduced flow (reduced flow = reduced pressure). At 1000 rpm over your max oil pressure you are surely dumping oil out of the relief valve, yet your pressure does not decrease and therefore neither does your flow. (positive displacement--increased speed=increased flow)

Gary Allan · Aug 21, 2006

You're trolling Todd ..but we'll play some more..it's a slow day

quote:

I'll say it again, Pump relief has no effect on filter bypass operation.

Can we take your word on that? Got proof?

quote:

When the is no pump relief ALL the oil goes through the oiling system

Good so far

quote:

most of the time all of it will be filtered

No problem there. I'll even say for the vast majority of the time ..probably 99.9% of the time.

quote:

EXCEPT when filter loading or thick oil causes an undue restriction at the filter media

Hmmm....what else does thick oil do in an automotive oil system

Darned if I have a clue

Todd, if you reread the thread ..all of these things I have discussed ad nauseam.

First, you've got to attempt to understand what is being said. This can be a challenge for even the brightest of our membership. I do not do well in technical writing. You've also got to have the ability to accept something that is counter to your current understanding.

Eventually (probably in about a year) I'll install both sets of gauges across a filter and show the relationship between relief and bypass operation. Loading is surely an effect. As you can see (if you looked at the offered links) really isn't much of an issue even in relatively long usage ..with relatively fine filters ..realized PSID in that application ..even with very heavy oil in very (relative for the oil used) cold temps produced limited PSID ...but was most likely in pump relief. (I know it due to experience but could not prove it for this event).

Is all PSID a result of pump relief action? NO.

But pump relief action absolutely produces PSID across the filter. It absolutely HAS TO.

another Todd · Aug 21, 2006

It has to? How can it? The filter and therefore bypass valve, does not even see the pump or its relief valve. It just sits there getting fed oil. At your 82 psi it doesn't know if oil is pouring out the relief valve or not. it is still getting "the required flow" to create 82psi of back pressure.

So tell me, when you reach 82psi and increase rpm further to open the pump relief valve, did your oil pressure drop? Of course not. Explain that one to me (i am kinda slow on the uptake). If you reduced the flow you had to reduce the pressure.

Gary Allan · Aug 21, 2006

Okay ..try this. Can you solve simple DC circuits with Ohms law?

If so ...solve a 1amp flow (no relief) through a 98 Ohm resistor ..and a 2ohm resistor. You'll drop 2 VDC across the 2Ohm (filter) and 98 VDC across the 98Ohm resistor (the engine) The applied voltage is 100VDC.

Now ..through magic ..we're gonna leave the applied voltage at 100VDC and run only .9 amps through the engine.

What does .9 amps produce in pressure drop through a 98Ohm resistor? It' produces 90% of 98VDC or 88.2VDC ...hmmmmm...but we've got 100VDC applied!!!!

88.2 from the big resistor to ground

...100VDC applied

That must mean that the (what appeared like in a strictly series circuit) 2 Ohm resistor (that was a variable impedence choke)now sees (drum roll, please!) 11.8VDC (ta-da!!)

but wait, you say!! Foul!! FOUL!! YOU SAY!!!

..but you didn't demonstrate the relief

But I did. I took a 100psi max pump and moved 1gpm through the filter/engine combo.

I then just lowered the temp with "magic" so that only 9/10 of that flow was needed to reach the relief state. To maintian 100VDC/PSI ..1/10 of a gallon/.1amp had to be shunted.

Max applied pressure ..reduced flow ....higher PSID

Gary Allan · Aug 21, 2006

There are minor rough edges to this. The main problem is viewing the filter as a static resistance. It's not. The other is the transition, in view, from a flow dictated circuit (non-relief) to a pressure dictated circuit (in relief).

It complicates comparisons.

another Todd · Aug 21, 2006

After careful consideration

I can understand why there might not be much psid with cold or thick oil (except the first second or two after start up. once the oil galleys are full, pressure would back up from the thick oil, causing similar pressures on both sides of the filter

Now then, if that is the case, the physics of this might indicate that you would have a higher psid with thin oil

But only if the filter was a higher restriction than the "engine" which I think you stated it was not.

As for the pump relief having no effect on filter bypass---you want proof? I'll see what I can find

Filter loading--I realize this doesn't seem to be an issue with engines running cleaner, but still, IF the filter gets loaded up excessively, the bypass will stay open, that is it's job.

Gary Allan · Aug 21, 2006

I think that we are in, somewhat anyway, violent agreement

another Todd · Aug 21, 2006

I didn't think you would ever come around

After reading that 11 page post you sent me to, by Red Bowtie, You make good points. Regarding PSID, with the bypass blocked, upon initial start up, he would have close to full pressure psid (72psid)accross the media until the galleys filled up and pressure backed into the filter. That I am sure is what crushed his core.

Here is another statement I'll make: Flow starts at the pump and moves forward towards resistance(direction of flow)--pressure starts at the resistance and moves backwards towards the pump(opposite of flow). Any physics majors care to back this up or shoot it down?

Gary Allan · Aug 21, 2006

quote:

Here is another statement I'll make: Flow starts at the pump and moves forward towards resistance(direction of flow)--pressure starts at the resistance and moves backwards towards the pump(opposite of flow). Any physics majors care to back this up or shoot it down?

That's my take on it. That's why I don't like people using the term "pressure drop". There is no such thing as a pressure drop unless the relief is open. There are pressure elevations that are, ultimately, seen at the pump. I frequently use the term 'backpressure'.

Once the relief is open ..that's no longer the case. The filter's PSID IS a pressure drop ..or ..as I assert ..indicates the reduction of flow to the engine that is expressed in PSID.

Filter guy · Aug 21, 2006

quote:

Originally posted by another Todd:
I didn't think you would ever come around

After reading that 11 page post you sent me to, by Red Bowtie, You make good points. Regarding PSID, with the bypass blocked, upon initial start up, he would have close to full pressure psid (72psid)accross the media until the galleys filled up and pressure backed into the filter. That I am sure is what crushed his core.

Well yes..the differential pressure did cause his filter to crush.

However it was in excess of 100PSID and probably in excess of 125PSID.

What Champ does as a matter of course is to quote the --minimum-- OEM spec for collapse.

That does not mean the element itself collapses at that rating. The E-core collapses at a much higher PSID than the service report figure and higher than the standard metal lock seam ( straight) core. They have the testing to prove it..

Just wanted to point that out when it comes to Red bowties collapsed element if you read through that thread..

another Todd · Aug 21, 2006

I just saw the post on the electrical equivelant

Oh boy, I never though I would have to review ohms law to figure out hydraulics. I cannot correlate the two with certainty.

Now regarding: The filter's PSID IS a pressure drop ..or ..as I assert ..indicates the reduction of flow to the engine that is expressed in PSID.

I don't think PSID is a reduction in flow! If 2gpm flows into the filter-then 2gpm must flow out of the filter. Reduction in pressure---yes,it is choked, reduction in flow--no. Oil for practical purposes is non-compressable, so what flows in must flow out or something breaks or leaks. And you will ONLY see meaningful PSID or filter bypass IF the filter is a higher resistance than the engine. If the engine is a higher resistance PSID will be near zero and no bypass will take place, which we agree is what happens most of the time. If this supports what you have been saying, then I've been tricked

. However I will add (and still looking for info to support)that it doesn't matter whether the pump is relieving or not, it does not effect bypass operation.

It can only relieve when enough flow is acheived to create the backpressure required to open the relief valve. If flow reduces, pressure reduces, valve closes. I think we are getting closer

another Todd · Aug 21, 2006

Filter guy. In order to achieve 125psid wouldn't the pump relief valve have to be stuck shut also. That is pretty high pressure. I thought Red Bowtie stated his oil pressure never exceeded 72 psi. Now if we could figure out how many square inches that core is, we could figure out just how many pounds of force were exerted upon it.

Gary Allan · Aug 21, 2006

quote:

I don't think PSID is a reduction in flow! If 2gpm flows into the filter-then 2gpm must flow out of the filter. Reduction in pressure---yes,it is choked, reduction in flow--no.

I thought you were in tune ..but I lost you again.

Yes, as I've said repeatedly to you when you're in a FLOW DICTATED situation ..there is very little PSID. The engine is the biggie.

HOWEVER

ONCE the relief is OPEN (1,2,3,4,5, take shoes off 6,7,8 ..err ..lost count darn) you are NO LONGER IN A FLOW DICTATED CIRCUIT. It's no longer 2gpm in ..2 gpm out. It's the pressure of 4gpm with the flow of 2gpm(or whatever). You're in a pressure dictated circuit. The PSID represents (in one abstract form or another that can be surely integrated by someone other then myself) ..or is the expression of, the flow that is no longer there (that took a hike out the relief). The harmonic ..the sag ..the missing link ..the phantom zone ..the imposter ..the fake ...the mere shadow ..the "apparent" as opposed to the real.

There's a sign post up ahead ..your next stop

But here!! This is an image that will encapsulate your participation in this thread and bring it all into one neat package for you. What you've been trying to say all along.

And G'Kar was asked, "What is Truth and what is G0D". G'Kar told of his feelings, reaching deep and telling in depth, and then was asked, "but what is truth ..and what is G0D?"
G'Kar replied, "Truth is the river, and G0D is the mouth of the river"

[ August 21, 2006, 11:32 PM: Message edited by: Gary Allan ]

another Todd · Aug 21, 2006

Gary, I agree with most of what you are saying but I think some of you examples are faulty, especially if it is correct that the "engine" causes a higher restriction to flow than the filter does. Your post of 10:26am---right after "Okay with that". (I don't know how to copy and paste it here sorry). I agree with the first statement. One side sees 82psi the other sees 60(pressure generated form 3 gpm through the engine). I am assuming for this example the pressure relief valve setting is 82psi?----OK so the pump side of the filter sees 82psi (and assuming the filter provides no resistance) The engine side must also see 82psi. It is the engine that causes the pressure--resistance to flow causes pressure. Flow is reduced if the relief valve is open, pressure will remain the same 82psi. If the backpressure was 60psi, the relief valve would close.(assumption-pressure relief set at 82psi) Given identical engine rpm, 4 gpm to engine= 80 psi, 3 gpm to engine =82psi and 1 gpm bled off as over pressure at relief valve. The engine cannot bleed off 4 gpm-only 3gpm so pressure rises until the relief valve bleeds off the pressure, the pump still puts out 4 gpm.
The relief vavle would not be open if the pressure was less than 82psi. It relieves "pressure" not flow. So if you have reduced flow ie. cold oil, pressure increases until relief valve opens and bleeds off pressure, you do have reduced flow at this point but it is not caused by reduced pressure.

Now enter filter bypass valve. It will open any time there is a restriction in the filter element that causes >10psi drop from the pump side to the engine side---assuming 10psi valve setting. This can be from cold oil or high RPM high flow situations. In the case of the filter causing the restriction---you could have 80 psi at the pump and 70 psi to the engine, then the filter relief would open the the pressure reduction will not exceed 10psi.

Make sense?

FLA1 Motorcraft filter & 100 psi oil pressure

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