Filter Flow Tests?

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Bob, I think I posted in the wrong thread.

Have you considered the idea that 25% PAO is not enough to make significant difference?

If you want to test PAO why not run 100% PAO or close to it. Walmart 5Qt. M1 5W30 jug.

If you want to test POE/TME run some Redline.

Just some ideas from the peanut gallery. I know you wanted to test the base stocks not the additives but with 3/4 of the base stock beeing the same I doubt you will ever see much difference. The first thing I noticed though is that the ring wear was lower as is to be expected.

This is signifacant because all synthetics should reduce iron wear. They will also reduce copper, tin and lead if their film strength is better then the oil they replaced. PAO base stocks are a bit stronger then convetional oils but not by much.THis is especialy the case when stock is only 25% PAO. I think that most of the copper reduction and slight lead reduction were due to slightly higer flow . This is just conjucture though.
 
Sorry John, but I don't agree with synth's having better film strength as you know it. I do agree a full synth has a better molecular film strength. Ok, what the heck am I saying..

On a molecular level, the design of a full synth is better as it will not break the molecules apart with oxidation as easily and will resist oil breakdown over a standard mineral over a longer period of time.

On a hydrodynamic level, a film strength is where you have a film of oil separating the two surfaces apart from each other with a wedge of oil which is produced by the pressure(or resistance of flow due to bearing clearances). Now, if we were to say that you were correct about the synth flowing better, that would also mean that the oil would squeeze out sooner than the other oil, allowing the oil to shear out sooner, which isn't the case as both should be flowing near the same otherwise, they would have different viscosity labels due to different flow rates.


Both having the same basic mineral oil, both measured out to be a 5w30 tested out by gravity flow tests at operating temp, would give it similar results. In the analysis you're looking at, the difference between the two 5w30's are not so much apart on wear that a +- percent could easily call them a near identical wear due to slightly different conditions given they are two separate runs. Point is, even with a full synth, there's more to wear protection due to flow and additive packages than base oil.

Heres an actual full synth that compares m1 tri to schaeffers full,
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=000414
Notice that those wear numbers are near the same.

In this analysis by twb, he showed the difference between oil flow with the same type of oil, notice the 15w40 again, showed to be slightly higher in wear over the 5w30 in this case.

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=000143

in this one, this was a comparison of schaeffers 10w30 blend against m1's full synth. This is most likely what you're wanting a full synth in comparison to the blend? Notice with same basic miles that the blend did a bit better. Was this the base oil doing it's job? no, imo, I'd put part of that on the additives more than the base oil alone.

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=000320

Point I'm getting at is, To claim the base oil has better film strength, you got to understand that molecular film strength is different than hydrodynamic film strength and that no doubt, synth's possess better resistance to breakdown over longer drains and provides better flow on extreme cold start ups. But, when it comes to hydrodynamic wedge film strength, this is all dependant on flow, pressure and additives more than synth or not. This is why you can see there are some extremely good mineral oils out there that can provide just as good wear numbers and in some cases even better than a full synth as there is no doubt that a full synth has a higher quality molecular film strength than the mineral.
 
If I remember correctly from an article I read,the purer the basestock(group I thru IV)the higher the film tension,but this could change once the basestock is additized IMO,the film thickness part could be not from the PAO itself,but if the PAO ran cooler that would tend to raise the viscosity thus raise the film thickness,I'm starting to think that this is not necessarily from reduced friction(from a PAO) per say but maybe from being a better heat transfer fluid.I believe I've heard somewhere that this is due to uniform molecular size.
I'm hoping to try this someday at work in a bearing box on a mill to see if this is so,and compare temperatures.
 
RB, "higher the film tension", maybe molecular film tension not hydrodynamic flim tension.

the biggest problem with this issue is that when people change over from a mineral to a synth they are changing additive packages and many times are changing viscosity over to a thinner oil. When you do that, then the question comes into play, base oil or additives?

Another point is that when all these tests are done on the bench to establish how a synth base oil outperforms a quality mineral, there is a big factor that is left out, the mechanics. How the mechanical components are affecting the flow, the filtration again flow, the clearances creating the resistance causing the pressure and a few other points that I'm missing.

Another point is that when talking about reducing temps vers causing variances of flow, let's not forget that barrier additives play a big role in this as well. A good barrier additive which seems that looking at the synth's voa's you'll notice that many are actually "loaded" up with barrier additives. I've looked at them and I find it interesting that all have high amounts. Amsoil, and redline both come to mind. Why is it that they require so much?, If the base oil is supposedly proving so much wear protection?.
Amsoil has higher levels of antiwear/zddp so no api. What sets their api rated oil xl7500 apart from their others(before they changed formulation earlier)? the zddp levels. Why is it that redline uses 600+ of moly and above normal limits of zddp? Do you see the trend here? Again, I've seen the papers, but when you're talking about a cubical engineer report vers real time info, voa's(high levels of barrier additives), oil analysis( difference between high quality mineral base oil's wear numbers near if not the same of synth's under normal drain intervals), and let's not forget the time where m1 failed to put moly/barrier additives in their first run of supersyn and wouldn't hold up to any other oil under the timken(why wouldn't it? the barrier additives were a problem and only the base oil was there), then flow data consideration as well, I just don't see it. There are way too many other variables that actually plays in this to state the fact that synth base oil protects and lowers wear numbers. Again, clarification, in normal drain intervals. In extended drains, can't agree more. In sub 0 flow issues, again, can't agree more. Fact is, I've yet to see any oil flow at startup in cold weather faster than what amsoil could do.

[ August 30, 2003, 08:56 AM: Message edited by: BOBISTHEOILGUY ]
 
I'd like to hear more about Chris A's question. Does a more restrictive filter cause more wear than a less restrictive one? In fact, I'd like more details on what makes a filter 'restrictive'.
In Bob's pressure test, Mobil1 and PureOne showed a big pressure drop after the filter, yet both companies' reps told me that there is less than psid over the filters. So, either somebody is lying, or more likely, testing involves a lot more than pumping oil through a filter and reading the difference in pressure. Of course, we can all say the company is always going to claim this or that, and maybe thar's true. But...
I'm not knocking Bob's test at all, I just want some more information. Why measure pressure? Why not measure how many gallons (or quarts, or whatever) are actually pumped through each filter over a certain amount of time? Wouldn't this add another piece to this puzzle?
One concern is that the many pleats and lots of filtering media in certain filters causes restrictions, yet the companies claim that they added more pleats to have just the opposite effect; more flow. So can we figure out which idea makes more sense? Or actually, which one is correct, often things that seem to make sense are not really correct. It feels counterintuitive to say that more material and more pleats provides better flow, but how do we know?
Here's all I can say, and it's based on personal observation, no UOA or anything scientific. My engine sounds and feels the same, and the oil pressure is the same on my gauge, no matter what filter I use. I notice the same amount of startup chatter with a PureOne as I did with a Fram or a Napa Gold. Of course, that's just a subjective opinion.
Can we find some real data to indicate what really is restrictive, and how much, and if it matters?
 
I am going to weigh in on the flow vs efficiency by talking about my old 1984 plymouth reliant.

The filters I used with that car were the old hastings depth filters. Used a cotton element that was approximately 1 inch thick that the oil had to flow thru. I used the fl1a equivalent which was much larger than stock for the 4 clinder motor in the car. Could pour a half quart of oil in the filter and it would soaked up leaving the center dry. I cut several of these apart, wish now I had saved an old one and a cut apart one.

I broke the car in on 10w-40 for 5000miles, then switched to mobil1 with 10k change intervals and filter changes at 5kmiles with a quart top off.

I lived next door to a guy who owned an independent shop. He told me I was crazy doing that with an untested oil. The engine would fall apart, eat itself up, etc.

To his suprise and my delight, the engine stayed very clean on the inside, ran great, and never had a problem except for the famous valve burning these cars did.

At 72kmiles the car burned a valve and had a constant miss. I decided to go ahead and tear it down and rebuilt it since my wife needed to go to shcool 60m round trips.

With supposedly the most restrictive filter on the market then, the bearings looked brand new, the hone marks were stillin the cylinder. When I took the pistons out there was no ridge whatsoever on the cylinder. I unbolted the rod caps and pushed the pistons out of the bore by hand. The inside of the engine was so clean that it looked like someone had worked on it with steel wool pads. No varnish, deposits, etc...

I put the stock ring size back in after miminmally honing the cylinders, did another 2500 mile break in and went back to the mobil 1 routine.

The thing I could tell was that after putting mobil1 in the car, on a cold day, it oiled immediately and there was never any noise on cold start like there was with dino oil.

I am starting to wonder after reading much on this board, if that immediate cold flow contributes to little wear. This car was driven hard. I kept it for 165k and sold it. I still saw it runnin around town 3 years later.

Remember, hastings depth filters with that cotton element had a reputation for very restrictive flow. Eyeballing seemed to confirm this, but with mobil1 never had a problem.

Admittidly this is just one data point.

Dan
 
Bob the synthetic will flow better due to uniform molecular size and bonding. If all your ball bearing are the same size and aranged in a uniform pattern then they must flow faster then random sized ballbearing bound in a vast aray of patterns.

What I am saying is that PAO is not that much better hydrodynamicly then mineral base stocks. It's advantage is in flow, oxidation resistence it's wide operateing temp spread and deposit control.

Esters are the synthetics that have incredable film strentgh and can out class PAO and mineral oils in this area.

If memory serves me correctly some esters can take 6 times as much force to force them out from between two metal plates compared to the same weight of mineral oil. QUite often people assume all synthetics are the same and then PAO gets to take credit for something that is should not.

We have also seen that some esters natural and synthetic can get under exsisting build up and penatrate the pores of the metal. Mineral oil does not show this as a charteristic and PAO's do not show this either.

I can under stand you not wanting to test a competiors product but I think that buy limiting the base stock to 25% PAO the test is bound to fail as a test of PAO base stock! What the test really shows is that Schafffers blend of 25% PAO and 75% mineral base product offers no advantage over mineral base stock only Schaffers in 5w30.
 
Well I should know by now nothing is as easy as it first appears.
It's been very busy at work and I haven't had much time to do the testing. I finally got to the testing last week but it provided some challenges and data that I will have to research some formulas to complete the full pore size calculations.

My bubble point (BP) test set consisted of a remote filter holder like the one Bob uses in many of his test. Clear ¼” tubing to the inlet and from the outlet.
For now I used calibrated lab bubble point equipment so that I could start with something very accurate and repeatable, an inexpensive version will follow. The equipment is simply a very accurate pressure gauge +/-.01psi and a very accurate mass flow meter and control +/- 1 cc/min air.
At first, I tried Alcohol but the BP was too low to find any differences among filters, gravity had too much of an influence. I switched to 10w-40 Chevron motor oil. A straight 40w or higher would be better. I may redo the testing with the heaver oil. Bubble point isn't always a straight and simple number. There is a pressure curve vs. mass flow, which describes the pore distribution. This is where I have to do some more research to make total sense of the data.

I tested two filters one Motorcraft FL-400S and one Puralator Pure One PL21095. As expected, the Motorcraft had a lower bubble point than the Pure One. Both filters were tested forward flow and I found I didn’t have to cut them apart, at least no yet. Both were tested with a mass flow of 5cc/min airflow.
The Motorcraft first bubble pointed at .29psi with large bubbles then immediately fell to a .16psi while it was continuously bubble pointing.
The Pure one first bubble pointed at .30 psi, with very fine and occasional bubbles. It went on further to .51psi before it fully bubble pointed as the Motorcraft did and then dropped to .40 psi for a continuous bubble point.
What does this mean?? Well I'm not about to draw any full conclusions yet until I do some more checking and review my calculations completely, but so far we can say the Pure One filter is much more retentive filter than the Motorcraft filter.
I'll eventually repost my full results with pic's and calculations. Please be patient
Tim
 
"Esters are the synthetics that have incredable film strentgh and can out class PAO and mineral oils in this area."

John,

It should state more like,

Esters are the synthetics that have a molecular film strength(not hydrodynamic) that can out class.. ect..


What I am saying is that PAO is not that much better hydrodynamicly then mineral base stocks. It's advantage is in flow, oxidation resistence it's wide operateing temp spread and deposit control

should read, PAO and Esters are not any better hydrodynamicly than mineral base stocks under normal conditions. Paos and Esters advantage is in flow under extreme temp conditions such as cold weather, oxidation resistence beyond normal drains(extended drains) it's wide operateing temp spread and deposit control[/i]

I always choke on this kind of next statement John,
If memory serves me correctly some esters can take 6 times as much force to force them out from between two metal plates compared to the same weight of mineral oil

Ok, last statement stated that it flows better, now it can take 6times as much force to force the synth ester out between two surfaces. Here's the problem with this statement, which is it, better flow(meaning it can flow out easier when two surfaces are compressed, thus less hydrodyamic film is left between the surfaces relying on the barrier additives(which btw, you've not explained the need for all the extra barrier additive if it can plate into the metal why need all the extra heavy barrier additives?) or is does it flow the same as the mineral oil between the two surfaces. Don't forget there is physics involved here. Can't have it both ways. BTW, how is viscosity of an oil determined?, isn't a measured flow of oil pass a given point for a given time mean that the oils viscosity is basicly the same? So if an ester synth and a mineral has the same Cst's, wouldn't that classify the flow of both the same?

I've yet to see what you have to prove better wear numbers with an ester such as redline over some of the higher quality minerals such as Schaeffers.

Sorry, just gonna have to do better than that to prove that the esters base oil can protect better under normal conditions. Put some extremes into the boat, I can see where it will not vary as much thus sustaining a longer oil life for longer drains, and such, but it's a wonder just how the heck we managed to get vehicles to last as long as they have with out synth esters or even pao synth's.

I've atleast would like an answer to why so much barrier additives in such a good base oil if it bonds with the metal and does all that protection.
And show me some difference in wear protection with uoa's show better wear numbers than some of the other high quality oils.

As for testing other oils, Sorry, not in my car, got way to many plans on extending my oil drains out past 10k after my next analysis using a blend that seems to have shown more than once its ability to keep up with all these so called big dog full synth's.

I don't think that the test pao failed but provided and proved that there is no difference in wear protection due to the base oil. To ignore the fact that pao synth is added to the base oil, should prove exactly the same with any other base oil for standard drains. There's no question the pao provided better oxidation/ and flow points among other points, but . Problem 2 for testing another oil is that there is no other oil with the same basic additive package with only a base oil changed, which cannot prove anything(again, the reason for this testing showing that it's more the additives that protect wear protection than base oils). The basic additive package must be the same and only the base oil must be the variable changed to show this point.
 
What's PAO??

Mark C
Adding more pleats (effective filtration area) to a filter only becomes more restrictive when the pleats are packed so tightly that they are no longer spaced apart their full depth. If the pleats are packed this tight then you essentially have only the upper portion of the pleats exposed to flow which means less EFA and less flow. I haven't cut the Pure One apart but I have a used one my bench ready. When I cut it apart, I'll post the total EFA and an opinion of how well the pleat pack is made.
 
quote:
Originally posted by Schultz:
Where is the graph from??
Click to expand...
I think the graph is one used to advertise the acdelco ultra guard fiters and is on the web page for that filter.

Dan

[ September 17, 2003, 09:43 AM: Message edited by: Dan4510 ]
 
Schultz - Dan 4510 is correct. It was pulled from Ac Delco's website some time ago (maybe a year or two).

Not sure the validity of the graph but interesting nonetheless.
 
Well first Bob thank for the corections. You corrected my text to almost exactly what had intended to communicate. Thank you!!

I like all the tests you do! They are always cool. I especial like the current bypassed full flow bypass only setup!!

Viscosity and Film strength do not always travel the same path. This is what seperates some synthetics from their conventional conterparts.
The tests to determine viscosity is vastly different then the test to determine film strength.

I think that my main point was to point out the flaws in your study if it was supposed to determine protection capabilitys of PAO base stock over conventional oil. Surely you can see that 25% PAO does not make the test a test of PAO at all! It would be the same as someone runing Delvac-1 and declareing it a test of ester based oils because it is 25% ester base. I do not remember if it is TMP or TME. I did not meant that the test was meaningless at all!

I just ordered some Redline oil today. I will run this through winter. After winter I will run a second OCI of Redline and then do UOA.

Bob when you tested oils on the falex/timken machine how did Redline do? WHat oil won that test? I heard about this test but have not been able to find it!

Bob what astm data do you want to see? I will ask Redline to send me the information. They might just provide it? If not what type of test did you have in mind?

I have to admitt that my experince with ester based oils in from import rceing and some rally raceing. My experinces are from visual tear downs and measureing not from UOA. I am still learning as well. I would love to see something more controlled then a raceing!!
 
Russ is right of course.
You could get a high (er) pressure drop by limiting the number of holes in the center tube - this might mislead folks into thinking: wow its really filtering.
whats probably need is a general basic flow rate that is needed (2 GPM? 3 GPM? will it vary by engine size??

- then some basic filter particle size test - common sense says that at some point getting out say 5 or 15 micron stuff is useless and counter productive.

What are the targets for these two - flow rate and particle removal?
 
I finally got around to writing this up and if anyone has any questions or debates about anything let me know.

Bubble point test and calculations to determine pore size
D = 4 s / P
D (m) = 4 s (N/m) / P (N/m2)

D = pore size diameter (meters)
s = Surface tension of the test fluid in air (Newton/meter)
Typically measured in dynes/cm – 1 dyne = 10-3 N/m
Chevron 10W-40 has a measured surface tension of 45 dynes
P = Pressure in Pascal’s (Pa) or Newton’s/square meter (N/m2)
1 psi = 6,894 Pascal’s = 6894N/m2


Bubble point test:
Bubble point (BP) is the pressure at which air begins to flow though the pores of a filter membrane. This test is very repeatable and commonly used in the filter industry for determining pore size, membrane and filter integrity. To be repeatable the same mass flow rate has to be used each time. Using a very low mass flow rate provides the BP pressure for the largest pores in the membrane. Pore distribution can be found by using consecutively faster mass flow rates until the BP pressure equals the dry flow pressure drop at the same flow. For simplicity and lack of time I only tested for the largest pores, it’s possible the nominal pore size could be half that of large pore size that I calculated.

Purilator Pure One PL-21095 (FL-400S replacement)
Each test was repeated twice with the same results, so I decided that was good enough. With the Purilator, I first saw sign of bubbles at .31 psi. These bubbles were very small about .010-.020”. After careful inspection, I would say this is either a leak at the bypass valve or a single point integrity failure. The pressure continued to climb to .51 psi before it truly bubble pointed, then it immediately dropped to .40 psi while continuously bubble pointing.

Calculating pore size using a mass flow of 5cc/min air and Chevron 10W-40

Pure One PL-21095
P=.51psi = 3516 Pa
s = .45 dynes/cm = .045 N/m2

D = 4 s / P
= 4 (.045)/3516
= 51 x 10-6meters
= 51 µm as the largest pore size

Motorcraft FL-400S
P=.29psi = 2000 Pa
s = .45 dynes/cm = .045 N/m2

D = 4 s / P
= 4 (.045)/2000
= 90 x 10-6meters
= 90 µm as the largest pore size

Using the above pore size calculations the pores in the Pure one are about 40% smaller than the Motorcraft filter. Notice the bubble points pressures also directly correlate to this number, so if you want a simple comparison there’s no need to do the calculation.
After cutting apart the Pure One it contained 63 pleats which measured 3.55” x .45” for a total EFA of 201 in2. The pleats were well spaced, having any additional pleats would likely reduce flow. The cartridge was seam sealed with a metal clip and potted into metal end caps with likely a hot melt. Once I get the digital camera and filter test set back together, I’ll follow this post with another that contains the pictures.

[ September 25, 2003, 10:45 AM: Message edited by: Schultz ]
 
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