Wear Relationship to Motor Oil Density
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ACD 10w30 = .8735
AMO 10W-40 = .8633
AFF 0W-40 = .8488
TRO 20W-50 = .8789
ACD does rock in the wear dept. Seems like the SG follows the cold temp viscosity. (imagine that!)
AMO 10W-40 = .8633
AFF 0W-40 = .8488
TRO 20W-50 = .8789
ACD does rock in the wear dept. Seems like the SG follows the cold temp viscosity. (imagine that!)
Can anyone explain sheer strength of the film of oil as it relates to density?
According to some of the numbers listed, a 20wt can/is close to a 50w density is some of the listed brands. Does sheer film strength seperate the oils in performance?
According to some of the numbers listed, a 20wt can/is close to a 50w density is some of the listed brands. Does sheer film strength seperate the oils in performance?
Esso XD-3 30wt - 0.888
Esso XD-3 20w20 - 0.884
I found my new 20wt summer oil!
Interesting....
XD-3 0w30 - 0.850
0w40 - 0.851
Esso XD-3 20w20 - 0.884
I found my new 20wt summer oil!
Interesting....
XD-3 0w30 - 0.850
0w40 - 0.851
Seems density is a reflection of viscosity and base oil quality, but the range in density is very small compared to range in viscosity from a 5w20 to a 20w50 of the same brand oil, all else equal. Viscosity is probably a better indicator of wear relationship. However, density may be a good indicator of base oil quality across the same grade.
Density has more to do with volatility & evaporation than anything else guys. Don't you remember basic chemistry?
Denser oils will evaporate slower at a given temperature than less dense oils. This means they will likely hold onto their more volatile components better and will last longer in higher temp environments.
It may have other relationships but this is one I know of for sure.
Denser oils will evaporate slower at a given temperature than less dense oils. This means they will likely hold onto their more volatile components better and will last longer in higher temp environments.
It may have other relationships but this is one I know of for sure.
TallPaul are you suggesting that the homogeny of the base oil's hydrocarbons has an effect on density?
for example a 30wt oil can be formulated from STP oil treatment and kerosene or it could be a molecularly uniform oil ? The latter appearing to be far superior to the former.
for example a 30wt oil can be formulated from STP oil treatment and kerosene or it could be a molecularly uniform oil ? The latter appearing to be far superior to the former.
Being the iconoclast that I am, I think I'll state what seems obvious to me:
1) The specific gravity of oil is the average of the specific gravity of each component, including the additives. Differences in density between oils may have little to do with the base oils, and more to do with the type and quantity of additives used.
2) The title of this thread "Wear Relationship to Motor Oil Density" begs the question: What wear? What exactly are we talking about: cam wear, bushing wear, chain wear, gear wear, bearing wear, piston wear, ring wear, cylinder wear?
3) How in the world would anyone test this without specifically formulating test oils without additives, or with absolutely identical additive packages?
4) Where are the references? Seems to me like everyone is going off on a wild goose chase, until someone finds some research papers that support Dr Hass' hunch.
As a point of reference, here are the specific gravities of oils that have been tested in the RS4:
RLI 5W-40 BioSyn - 0.895
Motul 300V 5W-40 - 0.893
Motul 8100 E-tech 0W-40 - 0.861
Castrol Syntec 5W-40 - 0.855
Mobil 1 0W-40 - 0.855
Motul 8100 X-cess 5W-40 - 0.854
Lubro-Moly Synthoil High Tech SAE 5W-40 - 0.850
Castrol TXT 505 5W-40 - 0.850
Elf Excellium LDX - 0.849
Amsoil Euro 5W-40 - 0.8413
The two best performing oils for wear are at opposite ends of the spectrum.
1) The specific gravity of oil is the average of the specific gravity of each component, including the additives. Differences in density between oils may have little to do with the base oils, and more to do with the type and quantity of additives used.
2) The title of this thread "Wear Relationship to Motor Oil Density" begs the question: What wear? What exactly are we talking about: cam wear, bushing wear, chain wear, gear wear, bearing wear, piston wear, ring wear, cylinder wear?
3) How in the world would anyone test this without specifically formulating test oils without additives, or with absolutely identical additive packages?
4) Where are the references? Seems to me like everyone is going off on a wild goose chase, until someone finds some research papers that support Dr Hass' hunch.
As a point of reference, here are the specific gravities of oils that have been tested in the RS4:
RLI 5W-40 BioSyn - 0.895
Motul 300V 5W-40 - 0.893
Motul 8100 E-tech 0W-40 - 0.861
Castrol Syntec 5W-40 - 0.855
Mobil 1 0W-40 - 0.855
Motul 8100 X-cess 5W-40 - 0.854
Lubro-Moly Synthoil High Tech SAE 5W-40 - 0.850
Castrol TXT 505 5W-40 - 0.850
Elf Excellium LDX - 0.849
Amsoil Euro 5W-40 - 0.8413
The two best performing oils for wear are at opposite ends of the spectrum.
What happens to the specific gravity when you pour oil into an engine and start changing the pressure and temperature? Is the specific gravity of the oil different at say 250F inside a main bearing with say a dab of contaminants including some soot and some H2S04?
Well then RI_RS4, if that is the case, then the whole arguement about the density actually dictating the best oils can be thrown out the window, as I see from your chart that Motul came in very close to the RLI oil, but Amsoil, at the bottom of the chart, performed 2nd best in your engine, after the RLI product.
At least it's thrown out the window for your particular engine. Which also goes to show just how many variables have to be accounted for, which would make any generalization statements about any oil totally wrong.
At least it's thrown out the window for your particular engine. Which also goes to show just how many variables have to be accounted for, which would make any generalization statements about any oil totally wrong.
Someone might want to research the density of oils with high traction coefficients. I seem to recall that naphthenic oils have higher traction coefficients, and these might have higher density because of all the aromatic rings.
As Dominic says, "Density has more to do with volatility & evaporation than anything else guys." I have no idea what the density of an STP/kerosene mix would be, but I was talking more in the context of normal motor oil that would sustain an engine for the long term, which STP/kero mix would not. Might be a fun way to get rid of a beater though.
However, homogenity of base oil would tend to correlate with quality of base oil and presumably also with density and lower volatility.
does density indicate molecule attraction in any way where higher densities suggest a stronger cohesive bond at the molecular level? or is that something else :S
This sums it up this is a dumb subject.
RI RS4 said and I 100% agree:
""How in the world would anyone test this without specifically formulating test oils without additives, or with absolutely identical additive packages?"'
This is the problem with doing any comparision over a long time frame with many oils in various engines with uncontrolled enviroments etc.
bruce
RI RS4 said and I 100% agree:
""How in the world would anyone test this without specifically formulating test oils without additives, or with absolutely identical additive packages?"'
This is the problem with doing any comparision over a long time frame with many oils in various engines with uncontrolled enviroments etc.
bruce
Except that tonne is not an SI unit. Nearly everyone that uses the metric system knows what it means, but it's not SI.
they call it a metric tonne
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