Thin or thick: an excerpt from a classic ASTM book
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Originally Posted By: Gokhan
It's not "5" as in SAE 5w30. It's "5" as in 0W-5.
That's not what it says, though. It says 5w, as in a 20w or 10w, which are actual grades of oil, though essentially obsolete and virtually impossible to find. Now, if you're accepting this book's information as fact, you can't at the same time just assume they're inventing new parlance and viscosities, particularly when SAE J300 says nothing about them. They didn't mean an SAE 5, because that doesn't exist on SAE J300, whereas SAE 5w does exist there.
It's not "5" as in SAE 5w30. It's "5" as in 0W-5.
That's not what it says, though. It says 5w, as in a 20w or 10w, which are actual grades of oil, though essentially obsolete and virtually impossible to find. Now, if you're accepting this book's information as fact, you can't at the same time just assume they're inventing new parlance and viscosities, particularly when SAE J300 says nothing about them. They didn't mean an SAE 5, because that doesn't exist on SAE J300, whereas SAE 5w does exist there.
Originally Posted By: Garak
Originally Posted By: Gokhan
It's not "5" as in SAE 5w30. It's "5" as in 0W-5.
That's not what it says, though. It says 5w, as in a 20w or 10w, which are actual grades of oil, though essentially obsolete and virtually impossible to find. Now, if you're accepting this book's information as fact, you can't at the same time just assume they're inventing new parlance and viscosities, particularly when SAE J300 says nothing about them. They didn't mean an SAE 5, because that doesn't exist on SAE J300, whereas SAE 5w does exist there.
The table on the right has what "5W" meant back in the day of the paper...you are 100% correct, 5W was, and is a grade...
Originally Posted By: Gokhan
It's not "5" as in SAE 5w30. It's "5" as in 0W-5.
That's not what it says, though. It says 5w, as in a 20w or 10w, which are actual grades of oil, though essentially obsolete and virtually impossible to find. Now, if you're accepting this book's information as fact, you can't at the same time just assume they're inventing new parlance and viscosities, particularly when SAE J300 says nothing about them. They didn't mean an SAE 5, because that doesn't exist on SAE J300, whereas SAE 5w does exist there.
The table on the right has what "5W" meant back in the day of the paper...you are 100% correct, 5W was, and is a grade...
Originally Posted By: Gokhan
Originally Posted By: Ethan1
The last sentence in the quote which you posted means that the test did not accurately simulate a typical engine.
That's not true. They used a real, typical engine. However, it was a bench test, not a field test. That's what the last sentence means.
What the last sentence means is that in actual service with reasonable drain intervals, the oil will load with various particles too small for any full flow oil filter to remove.
Therefore, the MOFT of this 5W oil might be breached with disasterous consequences over time and miles.
A better question WRT this paper might be so what?
There are minor advantages in bearing heating and therefore fuel use with thinner oils as well as less work required to pump a thinner oil, saving a tiny additional amount of fuel, but the difference in fuel consumption for a typical driver between a 0W-20 and a 10w30 are somewhere between slim and none.
Originally Posted By: Ethan1
The last sentence in the quote which you posted means that the test did not accurately simulate a typical engine.
That's not true. They used a real, typical engine. However, it was a bench test, not a field test. That's what the last sentence means.
What the last sentence means is that in actual service with reasonable drain intervals, the oil will load with various particles too small for any full flow oil filter to remove.
Therefore, the MOFT of this 5W oil might be breached with disasterous consequences over time and miles.
A better question WRT this paper might be so what?
There are minor advantages in bearing heating and therefore fuel use with thinner oils as well as less work required to pump a thinner oil, saving a tiny additional amount of fuel, but the difference in fuel consumption for a typical driver between a 0W-20 and a 10w30 are somewhere between slim and none.
I'll stick with 5W30 across my small fleet.
From another thread:
Originally Posted By: dparm
Someone actually asked the chief Corvette engineer about this as part of his Q&A series on CorvetteForum.com:
descartesfool asked:
What is the effect of changing from Dexos compliant 5W30 to Mobil 1 15W50 for the track and back for road use? Some cars which are used on track a lot such as Porsches and GT-Rs recommend Mobil 1 0W40 for all uses, with no changes required when driving on track. Would this oil be fine for track and street use in the C7? What are the negative effects of leaving the 15W50 after track days and driving on the road, and at what temperatures is it an issue, hot or cold?
Tadge answered:
GM Propulsion Systems has validated all Corvette engines to operate with the DEXOS 5W30 for all but the most extreme track conditions. We recommend the use of Mobil 1 15W50 when the vehicle is going to be used for high-temperature track operation as the higher viscosity range provides a greater degree of protection under the extreme stresses of that duty cycle. We like the extra lube performance in those conditions because, unlike some other manufacturers, driving on the track does not automatically void the warranty. However, daily driving use of the Mobil 1 15W50 on the street has not been validated, and as such we do not recommend its use where the operating temperatures can run lower. Some contributors to the thread correctly point out that few Corvette drivers operate their vehicles at extremely low temperatures, but as the manufacturer, we have to protect for that possibility. Another issue is that the 15w50 oil has higher phosphorus and ash content than we specify for factory fill. That is ok for track usage, but in long term street usage, those chemicals can compromise catalyst performance. As the manufacturer, we are expected to meet EPA emissions for a very long time. Lastly, the higher viscosity will also result in a small loss of fuel efficiency.
As for the Mobil 1 0W40, it was not available when we validated these engines and, in its currently available formulation, it also contains more phosphorus and ash than we specify. So, even if we validated the 0W40 for track use, we would still have to recommend reverting to a DEXOS 5W30 for daily street use.
Like all aspects of the auto industry, lubricants continue to improve over time. We work with Mobil and others to elevate the performance of their products and hence ours. We will continue to do that and when we have a better oil to ship in our engines or recommend for use on the track, we will do so.
GM wants the "thick stuff" when the going gets tough.
Originally Posted By: dparm
Someone actually asked the chief Corvette engineer about this as part of his Q&A series on CorvetteForum.com:
descartesfool asked:
What is the effect of changing from Dexos compliant 5W30 to Mobil 1 15W50 for the track and back for road use? Some cars which are used on track a lot such as Porsches and GT-Rs recommend Mobil 1 0W40 for all uses, with no changes required when driving on track. Would this oil be fine for track and street use in the C7? What are the negative effects of leaving the 15W50 after track days and driving on the road, and at what temperatures is it an issue, hot or cold?
Tadge answered:
GM Propulsion Systems has validated all Corvette engines to operate with the DEXOS 5W30 for all but the most extreme track conditions. We recommend the use of Mobil 1 15W50 when the vehicle is going to be used for high-temperature track operation as the higher viscosity range provides a greater degree of protection under the extreme stresses of that duty cycle. We like the extra lube performance in those conditions because, unlike some other manufacturers, driving on the track does not automatically void the warranty. However, daily driving use of the Mobil 1 15W50 on the street has not been validated, and as such we do not recommend its use where the operating temperatures can run lower. Some contributors to the thread correctly point out that few Corvette drivers operate their vehicles at extremely low temperatures, but as the manufacturer, we have to protect for that possibility. Another issue is that the 15w50 oil has higher phosphorus and ash content than we specify for factory fill. That is ok for track usage, but in long term street usage, those chemicals can compromise catalyst performance. As the manufacturer, we are expected to meet EPA emissions for a very long time. Lastly, the higher viscosity will also result in a small loss of fuel efficiency.
As for the Mobil 1 0W40, it was not available when we validated these engines and, in its currently available formulation, it also contains more phosphorus and ash than we specify. So, even if we validated the 0W40 for track use, we would still have to recommend reverting to a DEXOS 5W30 for daily street use.
Like all aspects of the auto industry, lubricants continue to improve over time. We work with Mobil and others to elevate the performance of their products and hence ours. We will continue to do that and when we have a better oil to ship in our engines or recommend for use on the track, we will do so.
GM wants the "thick stuff" when the going gets tough.
OVERKILL
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Originally Posted By: Gokhan
Originally Posted By: OVERKILL
I think this is a critical component here:
'... tried to "fail" engine bearings by operating them with extremely "light" viscosity oils during severe (although short) steady-state lugging and snap acceleration/lugging tests in a 3.8 L engine.'
I think this is the real critical component:
'Bearing distress during these tests was discovered to be more a function of engine mechanical parameters (initial bearing clearance and oil-feed pressure) than oil rheological properties.'
Therefore, it's the bearing and lubrication design that matters most, not the oil viscosity.
But that is in the context of this test, which takes into considering the duration, which was purposefully noted as being quite short, subsequently not driving up oil temperatures. You simply cannot have this discussion in any honest form while ignoring that key component.
Originally Posted By: OVERKILL
I think this is a critical component here:
'... tried to "fail" engine bearings by operating them with extremely "light" viscosity oils during severe (although short) steady-state lugging and snap acceleration/lugging tests in a 3.8 L engine.'
I think this is the real critical component:
'Bearing distress during these tests was discovered to be more a function of engine mechanical parameters (initial bearing clearance and oil-feed pressure) than oil rheological properties.'
Therefore, it's the bearing and lubrication design that matters most, not the oil viscosity.
But that is in the context of this test, which takes into considering the duration, which was purposefully noted as being quite short, subsequently not driving up oil temperatures. You simply cannot have this discussion in any honest form while ignoring that key component.
OVERKILL
$100 Site Donor 2021
Originally Posted By: Gokhan
It's not "5" as in SAE 5w30. It's "5" as in 0W-5. Such an oil hasn't even been proposed yet.
I read it as being an SAE 5W; an oil that meets only the 5W designation. There were many of these types of oils that existed "back in the day", for example you could get a 20W, which only met the cold temp side of things. According to J300, this gives us a viscosity floor of ~3.8cP, which makes sense given the lower limit for a 16 is 6.1.
EDIT: I see Garak and Shannow have already covered this part.
It's not "5" as in SAE 5w30. It's "5" as in 0W-5. Such an oil hasn't even been proposed yet.
I read it as being an SAE 5W; an oil that meets only the 5W designation. There were many of these types of oils that existed "back in the day", for example you could get a 20W, which only met the cold temp side of things. According to J300, this gives us a viscosity floor of ~3.8cP, which makes sense given the lower limit for a 16 is 6.1.
EDIT: I see Garak and Shannow have already covered this part.
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Straight 5 grade oil is thinner than ATF ...
This doesn't really cover my use case for thicker oil, that being, I drive a DI engine known for a lot of fuel dilution and has documented connecting rod bearing issues. As in, Hyundai cannot rebuilt engines fast enough to replace the ones that failed.
If my oil shears out of grade, I want it shearing from 30 to 20 or 40 to 30, not 20 to 16 or whatever.
I have the non-DI version of this engine in my Kia, it's fine on 5w20 but it consumes more, so I use 5w30 anyway, it has never consumed enough of that to move the level on the dipstick a perceptible amount.
If my oil shears out of grade, I want it shearing from 30 to 20 or 40 to 30, not 20 to 16 or whatever.
I have the non-DI version of this engine in my Kia, it's fine on 5w20 but it consumes more, so I use 5w30 anyway, it has never consumed enough of that to move the level on the dipstick a perceptible amount.
Not this stupid "thick vs thin" war AGAIN
Oh come on, what do you have against a [censored] of the usual suspects? This is the equivalent of their little treehouse.
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Regarding SAE 5W you guys are right that this is an actual grade. The closest thing to that will be SAE 5W-4 or SAE 0W-4 multigrade. However, SAE 4 or SAE xx-4 haven't even been proposed yet. SAE 8 that already exists has HTHSV = 1.7 cP.
Also note that grades like SAE 5W-8, 0W-8, 5W-4, and 0W-4 will actually usually be single grades in construction, as in most cases no VII will be needed for such small spreads or even negative spreads. They chose to use the multiples of 4 for the new SAE grades to eliminate consumer mixups, that's the reason for 5W-4 instead of 5W-5 if any such thing is proposed in the near future.
Also note that grades like SAE 5W-8, 0W-8, 5W-4, and 0W-4 will actually usually be single grades in construction, as in most cases no VII will be needed for such small spreads or even negative spreads. They chose to use the multiples of 4 for the new SAE grades to eliminate consumer mixups, that's the reason for 5W-4 instead of 5W-5 if any such thing is proposed in the near future.
Ketchup and rubber buns I say.
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