Why is Mobil 1 10w-30 thinner than 5w-30?
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it's more shear stable, or so it is said
Actually it's not thinner but is actually thicker at operating temp's.
M1 10w30 has a HTHS vis of 3.14 cP and for M1 5w30 it's lower at 3.09 cP.
See the attached which explains why:
https://bobistheoilguy.com/forums/posts/2000048/
M1 10w30 has a HTHS vis of 3.14 cP and for M1 5w30 it's lower at 3.09 cP.
See the attached which explains why:
https://bobistheoilguy.com/forums/posts/2000048/
I dont think you can make that leap. The sump thickness will be the thickness on the viscosity curve for the sump temp; many passenger car engines and the way they are operated wont subject any significant volume of the oil to HTHS environment, so it's a moot point. Other stressed engines will, but the sump temp and what the oil pump initially circulates would be more viscous and well below the HTHS 150C test temp. I could imagine the oil leaving the turbo bearing of a stage 2 WRX STi on a saturday night romp would get there, though
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ARCO, even if the oil isn't at normal max. operating temperature, the bearings and piston rings are still going to subject the oil there to very high shear rates, causing temporary viscosity loss if polymers are present in the oil. M1 5w30 is loaded with polymers and M1 10w30 has very little or none.
I understand this, and as stated I have speculated I had "sheard" PYB5w30SM in an impromptu street race into a 'water' consistency. As you see in my sig, I'm running M1 HM 10w30 wuth a 3.7 HTHS in the Toyota this Summer as an experiment.
The leap can still not be made that in operation the sump oil will heat to near 150C and be sheared to the mid 3 cSt range in Joe Commoner's Chevy Malibu 3.1 V6. The HTHS spec vis is not the typ sump vis.
To more thoroughly examine engine shearing, You would have to design a fixture to collect the oil leaving the rod/main bearings and/or spilling off cambox drain back, then in a timely manner assess the fluid temp and viscosity. This hard to accomplish given the instrumantation may heat or cool the fluid to way off initial (operational) temp.
Are not the bearings receiving a partially sheared and heated oil (oil pump shear, oiling oriface shear) then in microseconds the bearings/piston skirts/cams lobes are subjecting the fluid to elevated shear and/or temps, then the oil drains back and cools in the sump and (partailly or fully) regains its normal (reduced) operational temp and viscosity (90-110C / 9 - 11cSt) ready for another nasty go-round.
In sum, The cycle:
Cool-thicken > Moderate shear-Heat > High shear-High Heat > Cool-thicken.
The instantaneous viscosity will be different at any of the stages and the sump viscosity is the only one easily obtained.
The leap can still not be made that in operation the sump oil will heat to near 150C and be sheared to the mid 3 cSt range in Joe Commoner's Chevy Malibu 3.1 V6. The HTHS spec vis is not the typ sump vis.
To more thoroughly examine engine shearing, You would have to design a fixture to collect the oil leaving the rod/main bearings and/or spilling off cambox drain back, then in a timely manner assess the fluid temp and viscosity. This hard to accomplish given the instrumantation may heat or cool the fluid to way off initial (operational) temp.
Are not the bearings receiving a partially sheared and heated oil (oil pump shear, oiling oriface shear) then in microseconds the bearings/piston skirts/cams lobes are subjecting the fluid to elevated shear and/or temps, then the oil drains back and cools in the sump and (partailly or fully) regains its normal (reduced) operational temp and viscosity (90-110C / 9 - 11cSt) ready for another nasty go-round.
In sum, The cycle:
Cool-thicken > Moderate shear-Heat > High shear-High Heat > Cool-thicken.
The instantaneous viscosity will be different at any of the stages and the sump viscosity is the only one easily obtained.
Originally Posted By: steven88
i thought CST was the measurement they used for thickness of oil?
Yes, in a lab with no pressure on the oil. Oil viscosity changes greatly when pressure is applied to it (like in a bearing).
i thought CST was the measurement they used for thickness of oil?
Yes, in a lab with no pressure on the oil. Oil viscosity changes greatly when pressure is applied to it (like in a bearing).
Viscosity interrelates with other engine dynamic and is of no direct import just as Time doesnt exist - just particle movement.
Sorts of, " I dated a blond" (as in Syn over Dino)
Rather than, "She was 5 Foot 7" instead of 4 foot 10" (More import, like viscosity)
Then, "She is pregnant by me" (now we are getting to Effect, as does HTHS).
Sorts of, " I dated a blond" (as in Syn over Dino)
Rather than, "She was 5 Foot 7" instead of 4 foot 10" (More import, like viscosity)
Then, "She is pregnant by me" (now we are getting to Effect, as does HTHS).
Originally Posted By: ARCOgraphite
Viscosity interrelates with other engine dynamic and is of no direct import just as Time doesnt exist - just particle movement.
Sorts of, " I dated a blond" (as in Syn over Dino)
Rather than, "She was 5 Foot 7" instead of 4 foot 10" (More import, like viscosity)
Then, "She is pregnant by me" (now we are getting to Effect, as does HTHS).
I hear 'oil filters' and 'anti-drain-back valves' prevent that
Viscosity interrelates with other engine dynamic and is of no direct import just as Time doesnt exist - just particle movement.
Sorts of, " I dated a blond" (as in Syn over Dino)
Rather than, "She was 5 Foot 7" instead of 4 foot 10" (More import, like viscosity)
Then, "She is pregnant by me" (now we are getting to Effect, as does HTHS).
I hear 'oil filters' and 'anti-drain-back valves' prevent that
Originally Posted By: Tempest
Originally Posted By: steven88
i thought CST was the measurement they used for thickness of oil?
Yes, in a lab with no pressure on the oil. Oil viscosity changes greatly when pressure is applied to it (like in a bearing).
But with changes over time, even if its milli-seconds. Thick going in thinner going out - a sacrifice of iot nature; If its thin going In and thinner spraying OUT, with inadequate recovery period if it BROKE then, at some point you will have a part failure. The 100Deg cSt is important. If you think not, run a SAE 5 oil with a 2.9 HTHS and see how the engine sounds and runs.
Originally Posted By: steven88
i thought CST was the measurement they used for thickness of oil?
Yes, in a lab with no pressure on the oil. Oil viscosity changes greatly when pressure is applied to it (like in a bearing).
But with changes over time, even if its milli-seconds. Thick going in thinner going out - a sacrifice of iot nature; If its thin going In and thinner spraying OUT, with inadequate recovery period if it BROKE then, at some point you will have a part failure. The 100Deg cSt is important. If you think not, run a SAE 5 oil with a 2.9 HTHS and see how the engine sounds and runs.
This seems to be true.
A friend just gave me a few qts of M1 10-30.
When I looked up the specs, I was surprised by this anomaly also.
It is thinner that the 5-30, at least in what the M1 specs sheets show.
Maybe at 0 def F it is thicker - they did not list that.
A friend just gave me a few qts of M1 10-30.
When I looked up the specs, I was surprised by this anomaly also.
It is thinner that the 5-30, at least in what the M1 specs sheets show.
Maybe at 0 def F it is thicker - they did not list that.
Originally Posted By: ARCOgraphite
I understand this, and as stated I have speculated I had "sheard" PYB5w30SM in an impromptu street race into a 'water' consistency. As you see in my sig, I'm running M1 HM 10w30 wuth a 3.7 HTHS in the Toyota this Summer as an experiment.
The leap can still not be made that in operation the sump oil will heat to near 150C and be sheared to the mid 3 cSt range in Joe Commoner's Chevy Malibu 3.1 V6. The HTHS spec vis is not the typ sump vis.
To more thoroughly examine engine shearing, You would have to design a fixture to collect the oil leaving the rod/main bearings and/or spilling off cambox drain back, then in a timely manner assess the fluid temp and viscosity. This hard to accomplish given the instrumantation may heat or cool the fluid to way off initial (operational) temp.
The 150C temperature in the HTHS test was settled on after a lot of testing to correlate to engine operation. The sump temperature is not expected to be 150C. There are Google books online where you can read about the development work behind the test. I refer you to that.
I understand this, and as stated I have speculated I had "sheard" PYB5w30SM in an impromptu street race into a 'water' consistency. As you see in my sig, I'm running M1 HM 10w30 wuth a 3.7 HTHS in the Toyota this Summer as an experiment.
The leap can still not be made that in operation the sump oil will heat to near 150C and be sheared to the mid 3 cSt range in Joe Commoner's Chevy Malibu 3.1 V6. The HTHS spec vis is not the typ sump vis.
To more thoroughly examine engine shearing, You would have to design a fixture to collect the oil leaving the rod/main bearings and/or spilling off cambox drain back, then in a timely manner assess the fluid temp and viscosity. This hard to accomplish given the instrumantation may heat or cool the fluid to way off initial (operational) temp.
The 150C temperature in the HTHS test was settled on after a lot of testing to correlate to engine operation. The sump temperature is not expected to be 150C. There are Google books online where you can read about the development work behind the test. I refer you to that.
Originally Posted By: ARCOgraphite
Originally Posted By: Tempest
Originally Posted By: steven88
i thought CST was the measurement they used for thickness of oil?
Yes, in a lab with no pressure on the oil. Oil viscosity changes greatly when pressure is applied to it (like in a bearing).
But with changes over time, even if its milli-seconds. Thick going in thinner going out - a sacrifice of iot nature; If its thin going In and thinner spraying OUT, with inadequate recovery period if it BROKE then, at some point you will have a part failure. The 100Deg cSt is important. If you think not, run a SAE 5 oil with a 2.9 HTHS and see how the engine sounds and runs.
It's a physical impossibility for a 5wt oil to to have a HTHS vis anywhere near 2.9 cP. A 5wt with a 5 cSt will have a HTHS vis around 1.4 cP.
An oil with a HTHS vis of 2.9 cP will have a possible KV100 range from as low as 8 cSt (a high VI ester) to a high of about 11 cSt (a high polymer content oil). In an engine at normal operating temps' both the 8 cSt and 11 cSt oil will have the same operational viscosity.
That's why the HTHS vis trumps the KV100 vis spec'; it's a more accurate measure of an oil's viscosity in an operating engine. The simple and very cheap to perform kinematic 100C spec', not so much.
Originally Posted By: Tempest
Originally Posted By: steven88
i thought CST was the measurement they used for thickness of oil?
Yes, in a lab with no pressure on the oil. Oil viscosity changes greatly when pressure is applied to it (like in a bearing).
But with changes over time, even if its milli-seconds. Thick going in thinner going out - a sacrifice of iot nature; If its thin going In and thinner spraying OUT, with inadequate recovery period if it BROKE then, at some point you will have a part failure. The 100Deg cSt is important. If you think not, run a SAE 5 oil with a 2.9 HTHS and see how the engine sounds and runs.
It's a physical impossibility for a 5wt oil to to have a HTHS vis anywhere near 2.9 cP. A 5wt with a 5 cSt will have a HTHS vis around 1.4 cP.
An oil with a HTHS vis of 2.9 cP will have a possible KV100 range from as low as 8 cSt (a high VI ester) to a high of about 11 cSt (a high polymer content oil). In an engine at normal operating temps' both the 8 cSt and 11 cSt oil will have the same operational viscosity.
That's why the HTHS vis trumps the KV100 vis spec'; it's a more accurate measure of an oil's viscosity in an operating engine. The simple and very cheap to perform kinematic 100C spec', not so much.
Originally Posted By: CATERHAM
It's a physical impossibility for a 5wt oil to to have a HTHS vis anywhere near 2.9 cP. A 5wt with a 5 cSt will have a HTHS vis around 1.4 cP.
An oil with a HTHS vis of 2.9 cP will have a possible KV100 range from as low as 8 cSt (a high VI ester) to a high of about 11 cSt (a high polymer content oil).
Maybe I'm misunderstanding you, or you're talking about conventional? But I know Red Line 5w30 HTHS is 3.8
Oh wait, never mind! You said 5 weight. For some reason I was thinking you meant the 5w (winter rating). Sorry, my bad!!
It's a physical impossibility for a 5wt oil to to have a HTHS vis anywhere near 2.9 cP. A 5wt with a 5 cSt will have a HTHS vis around 1.4 cP.
An oil with a HTHS vis of 2.9 cP will have a possible KV100 range from as low as 8 cSt (a high VI ester) to a high of about 11 cSt (a high polymer content oil).
Maybe I'm misunderstanding you, or you're talking about conventional? But I know Red Line 5w30 HTHS is 3.8
Oh wait, never mind! You said 5 weight. For some reason I was thinking you meant the 5w (winter rating). Sorry, my bad!!
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