Would they all flow the same?

[MarkC]

Here's my observation.
My engine sounds and feels the same whether I use a Pure One, which allegedly is the most restrictive, or regular Purolator, whichh they say flows a great deal, or a Napa Gold, which is supposed to be in the middle.
Just by eyeballing the oil, it looks cleaner when using a Pure One, but that might not be attributed to the filter, who knows?

 

[Filter guy]

quote:

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Originally posted by Razl:
Filter Guy, I have the feeling you have some insight to our questions. You are hush about the new Mobil Ext filters

That's just cruel bringing it up. So how about it?

How frequently do FFs go into bypass?

On average, how much containments is released in the auto per 1,000 miles? Or on average, how many miles before a filter's media becomes clogged?

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I can't answer this.

Not that I wouldn't want to but you have to understand what filter manufacturers do...they design and develop filters. Not engines.

They don't do engine testing, they do filter testing.

So they don't ( at least in my experience of being in Champ, Fram, Wix, Donalson, Baldwin's labs) have engines to do the type of testing you've asked about.

I do think during the operation of the car that the by-pass valve kicks in from time to time but I doubt it stays "open" for any extended length of time. From what i've been told it's an instantaneous thing that ..say high revs..may open the valve but the flow pressure adjusts through the media and the valve shuts off almost immediately.

The real problem is at start up especially with "cold" oil. Champ does testing to minus 20 or 30 degrees or something like that with their cold filter test equipment.

Like i've said before..if the valve kicks open at 8-10psid.. and you've got 45 psi flow..that means 35 psid is going through the element. How much time does it take to get 1-2-3-4-5 psid more flow through the element to shut the valve off?

Where people get balled up is thinking that near 100% flow goes through the by-pass valve. The only way for that to happen is the oil is near frozen in the filter or the media nearly plugged. Those would be super extreme conditions.

 

[novadude]

I've long suspected that the Bypass valve is mainly there to handle pressure spikes, and to ensure that the the engine does not starve for oil under extreme circumstances.

For example.... you are loafing along at 1500 rpm on a two lane road... you want to pass someone, so you slam it down a gear or two, and the tach needle shoots to 5000 rpm. I'd guess your bypass valve would open to allow the required flow to get to the bearings "right now", instead of having all that flow back up and drive pressures real high on the inlet side of the media.

It is important to remember too that the pump has a bypass valve as well, and that it will "dump" when the pump pressure gets above the relief valve spring limit. The pump relief can only "dump" so much volume per time, and I'd imagine that the pressure on the inlet side of the filter could get quite high if you suddenly see instantaneous HIGH flow as you would in the example above, and the oil cannot move through the bypass fast enough. With no Bypass, this could lead to exploding filter cans and starved bearings.

Is my thinking correct? I guess what I am saying is the change in flowrate over time is a big factor to consider. If flow rate increased in a slow steady manner, we'd likely never need a filter bypass. Right or wrong?

 

[Ugly3]

quote:

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Originally posted by novadude:
I've long suspected that the Bypass valve is mainly there to handle pressure spikes, and to ensure that the the engine does not starve for oil under extreme circumstances.

For example.... you are loafing along at 1500 rpm on a two lane road... you want to pass someone, so you slam it down a gear or two, and the tach needle shoots to 5000 rpm. I'd guess your bypass valve would open to allow the required flow to get to the bearings "right now", instead of having all that flow back up and drive pressures real high on the inlet side of the media.

It is important to remember too that the pump has a bypass valve as well, and that it will "dump" when the pump pressure gets above the relief valve spring limit. The pump relief can only "dump" so much volume per time, and I'd imagine that the pressure on the inlet side of the filter could get quite high if you suddenly see instantaneous HIGH flow as you would in the example above, and the oil cannot move through the bypass fast enough. With no Bypass, this could lead to exploding filter cans and starved bearings.

Is my thinking correct? I guess what I am saying is the change in flowrate over time is a big factor to consider. If flow rate increased in a slow steady manner, we'd likely never need a filter bypass. Right or wrong?

---

The bypass vales in the filter would only open if the differential pressure across the filter exceeded the filter rating (generally 8 to 15 pounds or so). If I am running 1500 RPM my pump in putting out 5.25 gallons per minute. I mash the gas down and go to 5000 RPM the pump flow increases to 17.5 gallons per minute but the filter sees little of the added flow because the pressure releif valve in the oil pump will release the excess flow to the sump. My engine is at full presure and flow at about 2500 RPM (about 9 GPM flow) the RPM's above 2500 produve more oil flow but it is releived back to the sump. I doubt the filter would go into bypass mode very often from RPM spikes, even if it did go into bypass it would only be for a few seconds and the vast majority of the oil flow is being filtered even when in bypass mode. Not a problem in my view.

 

[millerl]

So I'm sitting here looking at my official 2005 Honda Accord Service Manual. Page 2-5, Oil Pump specs, says the internal pump relief valve opens at idle=10psi minimum, and opens at 3,000 rpm=44 psi min. So at idle (and even running rpm) the pump can't handle too much total system pressure (i.e. backpressure, or flow resistance from the filter) before it releases oil directly back to the sump.

The more interesting info though is on page 2-16 where it states: Oil Pump Displacement at 6,000 rpm = 52.8L(55.8 US Quarts)/minute. This is an oil flow of 13.95 gpm.

Clearly this Honda 2.4L engine requires a very free flowing oil filter (i.e., one that can handle ~14 gpm of flow). A restrictive filter (3-5 gpm) would force the bypass valve to progressively open allowing the excess flow to bypass the filter as the engine rpm increased.

The Honda Service Manual also states that a bypass valve is REQUIRED in the filter to prevent excessive pressure drop across the filter that would interfere with the hydraulic operation of the VTEC system.

I'm not too sure that a highly efficient filter designed for only 3-5 gpm will cut it on this Honda engine.

 

[Ugly3]

quote:

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Originally posted by millerl:
So I'm sitting here looking at my official 2005 Honda Accord Service Manual. Page 2-5, Oil Pump specs, says the internal pump relief valve opens at idle=10psi minimum, and opens at 3,000 rpm=44 psi min. So at idle (and even running rpm) the pump can't handle too much total system pressure (i.e. backpressure, or flow resistance from the filter) before it releases oil directly back to the sump.

The more interesting info though is on page 2-16 where it states: Oil Pump Displacement at 6,000 rpm = 52.8L(55.8 US Quarts)/minute. This is an oil flow of 13.95 gpm.

Clearly this Honda 2.4L engine requires a very free flowing oil filter (i.e., one that can handle ~14 gpm of flow). A restrictive filter (3-5 gpm) would force the bypass valve to progressively open allowing the excess flow to bypass the filter as the engine rpm increased.

The Honda Service Manual also states that a bypass valve is REQUIRED in the filter to prevent excessive pressure drop across the filter that would interfere with the hydraulic operation of the VTEC system.

I'm not too sure that a highly efficient filter designed for only 3-5 gpm will cut it on this Honda engine.

---

I am confused. I always thought the oil pump releif valve opened above a particular pressure, your book is indicating that the releif valve opens at 10 PSI at idle and at 44 PSI at 3000 RPM. So at idle you can't have more than 10 PSI of oil presure on the gauge, even when the oil is cold? I doubt it.

Additionally, your manual indicates that at 6000 RPM the pump output is about 14 GPM, however, they do not indicate what portion of the flow is diverted by the oil pressure releif valve.

Finally, when I asked Purolator about flow rates they said their filters meet or exceed the flow requirements of the car maker for applications the filter is spec'd for. I would expect this to be true for all major filter makers.

In the Grease oil filter study the most restrictive filter was the Pure One which flowed 1.2 GPM of 30w oil at 10 PSI and 70 degree temp. If the oil were at 200 degrees the flow increases approximatly 10 fold - or 12 GPM in this case. Now increse the pressure from 10 pounds to maybe 30 or 40 PSI and the flow increases more (from 10 PSI to 20 PSI the flow more than doubled in the Grease study). Doesn't look too restrictive to me.

 

[Gary Allan]

I'm with Ugly3 on this. I can't see how they have a different relief spec at different rpm/flow levels ..that's what produces the psi.

I would like to see that truly "quoted" verbetum and see where the hole is in this assertion. According to that ...no Vtech should have more than 10psi at idle regardless of oil visc or temp.

Now the Vtech system may have some oddity to it that allows "variable pressure relief" ...but it is an oddity that is uncommon and must be compensated for in some other manner.

Filtration media density, in the confines of the limited range between the misnomered high flow and restrictive that we're talking about (we're not talking tp bypass density) is a non-factor.

 

[MarkC]

Numbers I have found indicate that Purolator Premium Plus flows the most(at least in that test) at 17.2 gpm, followed by K&N, ay 14.7. The most "restrictive " was Pure One at 5.3, followed by Mobil 1 at 8.1, AC at 8.5, and Wix at 9.1.
i'm just not sure , as I said originally, that these kinds of tests accurately reflect real world results. I've used all these filters except Mobil 1 and the only difference I could notice was that the oil 'looked' cleaner with the pure One, but that's a subjective thing. I noticed no difference in engine noise or anything else.
I'll be doing a used oil analysis next wekk, that OCI I used a Napa Gold filter, currently I have a Pure One on there, I can do a used oil analysis on that oil as well(it's the same oil), but I'm not sure that will really be helpful info.

 

[novadude]

quote:

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My engine is at full presure and flow at about 2500 RPM (about 9 GPM flow) the RPM's above 2500 produve more oil flow but it is releived back to the sump.

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Yeah... you are right... I guess I was forgetting that you are likely already at max pump relief pressure at 2500 RPM, and if the pressure stays the same, flow is not increasing. If you are at max pump pressure, that means that the valve is already dumping flow at 2500 rpm. That's what I get for typing before thinking it through...

Perhaps the filter bypass only exists to protect against plugged filters, and cold starts with high viscosity oil?

 

[Ugly3]

quote:

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Originally posted by MarkC:
Numbers I have found indicate that Purolator Premium Plus flows the most(at least in that test) at 17.2 gpm, followed by K&N, ay 14.7. The most "restrictive " was Pure One at 5.3, followed by Mobil 1 at 8.1, AC at 8.5, and Wix at 9.1.
i'm just not sure , as I said originally, that these kinds of tests accurately reflect real world results. I've used all these filters except Mobil 1 and the only difference I could notice was that the oil 'looked' cleaner with the pure One, but that's a subjective thing. I noticed no difference in engine noise or anything else.
I'll be doing a used oil analysis next wekk, that OCI I used a Napa Gold filter, currently I have a Pure One on there, I can do a used oil analysis on that oil as well(it's the same oil), but I'm not sure that will really be helpful info.

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Getting a used oil analysis without total particle counts will tell you little to nothing about the effectivness of an oil filter. The particles included in an standard used oil analysis are too small to be picked up by any filter.

 

[Mamala Bay]

quote:

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Getting a used oil analysis without total particle counts will tell you little to nothing about the effectivness of an oil filter. The particles included in an standard used oil analysis are too small to be picked up by any filter.

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I knew a Vietnam mechanic and he always stated flow was the most important thing. He was dealing with heavy military equipment.

One question is that engines and oil is so much more efficient, how much of a difference will restricted flow cause in an modern domestic(gas) engine. I can understand racing and heavy equiptment operations where the oil demands are a very necessity.

I would think at start up when the oil is thick, flow would be an ideal situation. But at operating conditions would certain high performance engines need that flow to protect the engine.

 

[3000GT VR-4]

Do we really care if the filter is in bypass mode some of the time? As long as the majority of the oil is being filtered well most of the time, we're taking the crud out and pumping really clean oil through the engine. Are we really better off with ALL the oil going through coarser media and letting bigger particles into the bearings? Seems to me we want the finest possible filtration, even if it creates a bit of a restriction, forcing the bypass valve to open occasionally.

 

[427Z06]

quote:

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Originally posted by millerl:
So I'm sitting here looking at my official 2005 Honda Accord Service Manual. Page 2-5, Oil Pump specs, says the internal pump relief valve opens at idle=10psi minimum, and opens at 3,000 rpm=44 psi min.

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Unless they've changed the wording from the 2002 Honda Accord Service manual, it states under the oil pressure test section:

code:

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Allow the engine to reach operating temperature(fan comes on at least twice) the pressure should be:



Engine Oil Temperature: 176F (80C)

Engine Oil Pressure:

At Idle: 10 psi minimum

At 3,000 RPM: 50 psi minimum (71 psi for V6)

---

No variable oil pump pressure relief valves on these engines. Must be a translation problem.

And just to throw my 2 cents in: I think running some numbers, like Ugly3 did, demonstrates that when the engine oil is hot, a new filter has no problems flowing enough filtered oil to the engine. When the engine oil temp is below something like 120F, you can almost bet some oil goes through the oil bypass valve. One can decide for themselves whether this is important or not over the very long run.(I can tell you that Honda thinks it's important enough that they have an additional screen filter to the VTEC system.) The unknown that remains in my mind is, what happens after you have something like 3K-5K miles on a particular filter. That is, do some filter designs maintain the same flow curve over the useful life of the filter.

The truly obsessed get tired of talking to so called "filter experts" and get a bypass filter.

[ February 14, 2005, 02:09 AM: Message edited by: 427Z06 ]

 

[427Z06]

quote:

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Originally posted by Gary Allan:

The flow, unless the internal relief springs are breached, always remains the same. Now, as I said, the filter itself may be in bypass ..but I would think that this would be brief since the fully enveloped oil system would also raise the downstream pressure. The oil can is a BIG chamber compared to the (maybe) 1/2 square inch pickup tube in the sump ..or the return line that you thread the filter to. 5 gpm is not a radical flow to produce out of a 1/2" hose ...try thinking of standing there for 1 min holding a hose to fill a 5 gallon bucket ..you'ld get bored doing it. And that is about the max flow the pump can produce. I think that my HV pump is rated around 8 ..or maybe 10 gpm.

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I would think that one must take in account the laminar flow in the pipe and bearings versus the highly turbulent flow through the filter media.

Ready for some Reynolds numbers calculations?

 

[Gary Allan]

quote:

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Ready for some Reynolds numbers calculations?

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(envision Ronald Reagan voice as he stood on the podium at the debates)

"There you go again."

I'm sure that there's a whole other level of perception on our fluid circuits here.

But I'd say that for most of us ..hmmmm...not bottom feeders ...ah ..those who can forage in the lower hanging branches ...we can reduce the filter to the "black box" where the in and the out pretty much look the same. We can gaze in awe at the sub-processes that go on inside it with looks of

and

on our faces.

quote:

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The truly obsessed get tired of talking to so called "filter experts" and get a bypass filter. [Big Grin]

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That is one way to cope with the confusion.

 

[Gary Allan]

quote:

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I'm willing to bet that there are no black boxes at your house that haven't been broken into at least once.

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!Warning! No user serviceable parts inside. That just begs to be explored.

There are also very few tags on my pillows or mattresses.

DO NOT REMOVE UNDER THE FEAR OF THE PAIN OF DEATH.



You know me all too well..

 

[millerl]

Yes, the Service Manual has been changed since 2002. The engine series apparently was updated in 2003, and is the same from 2003 through 2005.

For the identical item you quoted above, the 2005 Service Manual, page 8-5, step 3, states:

code:

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Engine Oil Temperature: 176F (80C)

Engine Oil Pressure:



At Idle: 70 kPa (0.7 kgf/cm2, 10 psi) min.

At 3,000 rpm: 300 kPa (3.1 kgf/cm2, 44 psi) min.

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For Gary, who asked earlier for the entire text to be quoted, here goes:

2005 Honda Accord Service Manual:

Page 2-5, Specs, Engine Lubrication, Oil Pump:

code:

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Relief valve, oil pressure with oil temperature at 176F (80C):



At Idle: 70 kPa (0.7 kgf/cm2, 10 psi) min.

At 3,000 rpm: 300 kPa (3.1 kgf/cm2, 44 psi) min.

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Page 2-16, Design Specifications, Engine:

code:

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Oil pump displacement:



At 6,000 rpm: 52.8L (55.8 US qt)/minute

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I sincerely hope I didn't take anything "out of context" in my earlier remarks.

So, given what the service manual states, is it not correct to draw the conclusion that a filter for this particular engine should not be very restrictive?

 

[427Z06]

quote:

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Originally posted by Gary Allan:

quote:

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Ready for some Reynolds numbers calculations?

---

(envision Ronald Reagan voice as he stood on the podium at the debates)

"There you go again."

I'm sure that there's a whole other level of perception on our fluid circuits here.

But I'd say that for most of us ..hmmmm...not bottom feeders ...ah ..those who can forage in the lower hanging branches ...we can reduce the filter to the "black box" where the in and the out pretty much look the same. We can gaze in awe at the sub-processes that go on inside it with looks of

and

on our faces.

---

I'm willing to bet that there are no black boxes at your house that haven't been broken into at least once.

 

[Ugly3]

millerl - I sincerely hope I didn't take anything "out of context" in my earlier remarks.

I think you have. I see nothing in the specs that addresses the oil pump releif valve settings. All the specs are "min" values not "max" values.

You are supposed to get a min of 10 PSI at normal temps at idle. At 3,000 RPM you are supposed to get a min of 44 PSI. Certainly could be higher, particularly when the engine is cold.

The pump flow data suggests that at 3000 RPM your pump output will be approximatly 7 Gallons per minute. At 6000 RPM the flow could be 14 gallons per minute if the oil pump releif valve allowed the oil pressure to reach 88 PSI.

At 6000 RPM at normal operating temps what does the oil pressure gauge read? That will tell you how close to a 14 gallon per minute flow rate you are running.

 

[Gary Allan]

millerl

For more precedence setting events ..again I agree with Ugly3 here.

Few know what their internal relief settings are. I know mine only since I purchased the HV oil pump in my engine ...and I'm up against its internal relief all the time except at idle ...hot ..cold..all the time off idle.


The main cause of this debate is our assumptions of pressure differential at various states of viscosity. One would naturally assume that in more viscous states, differentials would be higher. This, I think, is an unsubstantiated belief. We don't know what effect the viscous fluid provides in backpressure.

We can look at the media as a mass of micro orifices. Orifices create trubulant flows that are out of whack with normal flow restrictions, creating non-linear pressures for the same flow rates. This effect, IMHO, is somewhat thrown out the window if your downstream restiction exceeds this impedence.

For example, I've got a 20 x 2" 1um filter plumbed on my Caravan. If I did my figures right, I've got 125 square inches of media at a 1um nominal. It has a 1 square inch center tube. That means that it goes from 125 sq" of media down to about 63 sq" of media. Much smaller/lower than our pleated medias of far less restrictive material. With 20 weight oil, I see 2 PSID ..all the time. It starts out @ 82 psi and drops to as low as 22 psi (32 typical). If I use heavier weights ..I may go to a 4 PSID. In this case the filter is a non-issue.

I think that it is for just about everyone else too.

We're basing our impressions by one, and only one, point of reference (the oil pressure guage and the assumption that it (the filter) represents the most restrictiive point in the oil circuit. There are many "chokes" and variations in the conduits that the oil flows through. They too are impacted by viscosity. Enough so that I believe that they allow them, given the design of our filters (large chamber), to react in a more linear/resistive manner.

I think that they're factored to be a non-factor, for the most part. Again, this is just my opinion based on my observations ...so take it FWIW