brand x oil is thinner than brand y oil question

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some background info:
just for kicks i did a test with conventional (dino) oil 5W-30 and 10W-30
put some of each in 2 clear plastic cups and tested both at room/garage temperature (60F) and the refrigerator (38F) and the freezer -2F
the 5W-30 looked thinner in all cases. obviously, the difference was more subtle at room temp vs. the freezer.
i also got my wife involved and she confirmed the results
smile.gif


another background info:
In "7.5Wx30 Oil" thread i asked about 50/50 mix of 5W-30 and 10W-30 producing 7.5W ...
kschachn, OVERKILL and others commented and correct me if i am wrong but the conclusion was that:

1-
There is no spec/designation for 6,7,7.5,8W etc. only 0W, 5W, 10W ... at least for auto oil.
sounds like there is 7.5W (another thread) for motorcycles but for that’s beside the point here.
2-
For all practical purposes, it is not practical/feasible/useful to have any classification in between 0,5,10W ...

as a result, 50/50 Mix will no longer meet the 5W spec and most likely be considered a 10W ...
Not wanting to split hair ... i can totally understand the above logic.


another thing leading to my question:
Based on the above logic, let's say that:
company A has an oil that barely misses the 0W spec and gets the Winter classification of 5W
company B (or even company A) has an oil that narrowly makes the 5W spec and is classified as 5W
correct me if i am wrong here but Oil A and B can practically (mathematically?) be 5W (4.9W) apart and both be classified as 5W

now my main question:
when people say brand x 5W-30 is "thinner" than brand y 5W-30 ... is it because of the reason above (oil A vs. B)
or am i over-simplifying things?
 
There are definite ASTM tests that determine which XW-XX viscosity an oil meets. Of course there is a range of numbers at the testing temperatures at each viscosity that would allow one oil to be "thicker or thinner" than other oils at low temps, high temps, and anywhere in between. A graph could be plotted showing a complete viscosity curve if measurements were made for all temperatures in between.

For example, generally a full synthetic high mileage oil can be more viscous at all temps than their non-HM counterparts, yet still have the same viscosity label, such as 5W-30. I believe they are formulated this way to maximize fuel economy for the newer cars (meeting all the current oil specs when a car is new for warranty, etc) but later as the engine begins to consume oil, the HM formulations bump up the viscosity some as one way to slow the consumption and leaks, yet still remain within the 5W-30 specs.
 
Originally Posted By: OilUzer

when people say brand x 5W-30 is "thinner" than brand y 5W-30 ... is it because of the reason above (oil A vs. B)
or am i over-simplifying things?


Usually in discussion on this site, people like to refer to the HTHSV when distinguishing one oil of the same grade as 'thicker' or 'thinner' than the other oil of the same grade. I don't recall a discussion in reference to the CCS and MRV when discussing 5W and higher varieties; usually those discussing cold viscosity just leave it at "0W grade", and then get into CCS and MRV values of various 0W graded oils to compare cold viscosity.

WRT to splitting W grades, I'm sure it's already been mentioned numerous times that we're talking about a 5 degree Celsius temperature difference in qualification between them, so what insights do you feel can be more readily conveyed in doing so?
 
When I say that one oil is thinner than another, I am referring to the op temp viscosity. I don't really care about what it's like sitting in the driveway (that's what happens when you live in Cali). So I have heavy 30's and light 40's and such in mind. That's where the wear curves are and fuel consumption, etc. At op temp ...
 
if we are talk about "relatively" a thin or thick oil, does it really matter what temp we are sampling it at?
 
Originally Posted By: OilUzer
but Oil A and B can practically (mathematically?) be 5W (4.9W) apart and both be classified as 5W


As has been explained ad nauseum in the various recent threads, they are grades, which are band, and performing "mathematical" equations on them is not possible.

e.g
SL_EMspectrum.jpg


What mathematical process would you use to describe the things that are in the fringe region of Xrays and UV light, or visible light and Infra Red ?

ysult.5 ??
bleinf.5 ??
 
Originally Posted By: Shannow
Originally Posted By: OilUzer
but Oil A and B can practically (mathematically?) be 5W (4.9W) apart and both be classified as 5W


As has been explained ad nauseum in the various recent threads, they are grades, which are band, and performing "mathematical" equations on them is not possible.

e.g
SL_EMspectrum.jpg


What mathematical process would you use to describe the things that are in the fringe region of Xrays and UV light, or visible light and Infra Red ?

ysult.5 ??
bleinf.5 ??


Thanks for the example, however let's make a simpler analogy. as someone explained in another thread with the grading system:
- student 1 scores 100 on a test and gets an A
- student 2 scores 90 on the same test and gets an A
- student 3 scores 89 on the same test and gets a B
one can argue that:
student #2 soft/thin A is not far from student #3 strong B and for all practical purposes they are almost the same!

To further clarify my question, is it possible that:
- oil A has a true 2.51W which is closer to 5W than 0W so it gets a classification 5W.
- oil B has a true 7.49W which is closer to 5W than 10W and get the same classification of 5W.
oil A and B are 4.98W apart but they are both classified as 5W.
based on that, can you conclude that oil A is a "thinner" 5W than oil B?

I also know that xW classifications jump from 0W to 5W and 10W, etc. and are not infinite and I understand why (it is not practical) but in real world, how can you force the oil/molecules to follow the 0, 5, 10W standard? hence 2.51W or 7.49W in my example.

This was basically my question. Not sure if it works this way and as I mentioned, maybe I am over simplifying or misunderstanding things.
again, I was not trying to reach a conclusion in my original post, it was a question which I thought may? explain the "thinner" oil theory!

Thank you!
 
Originally Posted By: Shannow
Best double troll act in the history of BITOG...congratulations.


not sure where this is coming from!!!!
if you feel or think that you are being "trolled", please ignore this discussion.
you don't have to participate!

btw, if it matters to you, it is much easier for me to make an example with the grade system than the visible light spectrum.
someone else just used the grade system in another one of my threads and it was fresh in my mind ...
didn't mean to offend you or criticize your example!
 
and one more thing, I had to lookup "double troll" ... lol
first time I have ever been accused of any trolling let alone "double trolling"
smile.gif


I am not an internet guy. I am on VERY few websites (sports & car & recently this oil site) and hardly ever post anything! it goes thru cycles you know ... I am sure my "oil" related interest will die off sooner or later.
since i bought a car that requires 0W-20 i joined this site and got interested in oil ... every time i did a search for 0W20 it took me to BITOG!!!
also this site has tons of other information and I like it! it has become my "go to" web site for anything car related and more.
 
Originally Posted By: OilUzer
I also know that xW classifications jump from 0W to 5W and 10W, etc. and are not infinite and I understand why (it is not practical) but in real world, how can you force the oil/molecules to follow the 0, 5, 10W standard? hence 2.51W or 7.49W in my example.

The real answer, or best answer, at least, is that the viscometric properties of a given oil will fall somewhere on SAE J300. Where they fall dictates how the oil is labelled. Certain things are also likely to go hand in hand. A 10w-30 ILSAC, for instance, will exceed the 10w-XX limits fairly handily (but will not meet the 5w-XX limits) and will have a lower HTHS, just above the minimums for the grade. A 10w-30 HDEO will exceed the 10-XX limits much more closely and have an HTHS of 3.5 or higher. So, the 10w-30 ILSAC would already be what you consider a 7.5w-30. Except, however, it's not, because if it's a 10-XX but not a 5w-XX, it has to be labelled as a 10w-XX, and if it's meeting 5w-XX requirements, it has to be labelled as 5w-XX.
 
Originally Posted By: OilUzer


Thanks for the example, however let's make a simpler analogy. as someone explained in another thread with the grading system:
- student 1 scores 100 on a test and gets an A
- student 2 scores 90 on the same test and gets an A
- student 3 scores 89 on the same test and gets a B
one can argue that:
student #2 soft/thin A is not far from student #3 strong B and for all practical purposes they are almost the same!

To further clarify my question, is it possible that:
- oil A has a true 2.51W which is closer to 5W than 0W so it gets a classification 5W.
- oil B has a true 7.49W which is closer to 5W than 10W and get the same classification of 5W.
oil A and B are 4.98W apart but they are both classified as 5W.
based on that, can you conclude that oil A is a "thinner" 5W than oil B?

I also know that xW classifications jump from 0W to 5W and 10W, etc. and are not infinite and I understand why (it is not practical) but in real world, how can you force the oil/molecules to follow the 0, 5, 10W standard? hence 2.51W or 7.49W in my example.

This was basically my question. Not sure if it works this way and as I mentioned, maybe I am over simplifying or misunderstanding things.
again, I was not trying to reach a conclusion in my original post, it was a question which I thought may? explain the "thinner" oil theory!

Thank you!





If you want to make those types of distinctions, you can't use the W rating system, period. It's neither designed to, or capable of, conveying anything further about the oil than it's SAE J300 Winter classification.
You can compare oils in the way you want to, but you'll have to use the appropriate data like CCS/MRV/Temperature and possibly VI.
 
Originally Posted By: Garak
The real answer, or best answer, at least, is that the viscometric properties of a given oil will fall somewhere on SAE J300. Where they fall dictates how the oil is labelled. Certain things are also likely to go hand in hand. A 10w-30 ILSAC, for instance, will exceed the 10w-XX limits fairly handily (but will not meet the 5w-XX limits) and will have a lower HTHS, just above the minimums for the grade. A 10w-30 HDEO will exceed the 10-XX limits much more closely and have an HTHS of 3.5 or higher. So, the 10w-30 ILSAC would already be what you consider a 7.5w-30. Except, however, it's not, because if it's a 10-XX but not a 5w-XX, it has to be labelled as a 10w-XX, and if it's meeting 5w-XX requirements, it has to be labelled as 5w-XX.


Originally Posted By: PeterPolyol
If you want to make those types of distinctions, you can't use the W rating system, period. It's neither designed to, or capable of, conveying anything further about the oil than it's SAE J300 Winter classification.
You can compare oils in the way you want to, but you'll have to use the appropriate data like CCS/MRV/Temperature and possibly VI.


thank you guys!

it makes sense and kind of reaffirms my original intuition ...
btw, i had to lookup a lot abbreviations you guys throw at me! lol

it makes sense not to use xW rating in my logic!
i was trying to figure out why one 5W oil is different than other 5W (i used the word "thinner") and shouldn't have used the existing standards for my example. it was easier using the xW system to convey my point but i can see that it is not a good analogy (discrete vs. continuous) and xW system is not a continuous system!

i assume we can conclude that:
basically if 2 oils are pigeonholed into a given grade/classification, it doesn't make them equal!
 
Originally Posted By: bmwtechguy
There are definite ASTM tests that determine which XW-XX viscosity an oil meets. Of course there is a range of numbers at the testing temperatures at each viscosity that would allow one oil to be "thicker or thinner" than other oils at low temps, high temps, and anywhere in between. A graph could be plotted showing a complete viscosity curve if measurements were made for all temperatures in between.

For example, generally a full synthetic high mileage oil can be more viscous at all temps than their non-HM counterparts, yet still have the same viscosity label, such as 5W-30. I believe they are formulated this way to maximize fuel economy for the newer cars (meeting all the current oil specs when a car is new for warranty, etc) but later as the engine begins to consume oil, the HM formulations bump up the viscosity some as one way to slow the consumption and leaks, yet still remain within the 5W-30 specs.


forgot to mention, good info as well!
 
Originally Posted By: OilUzer
basically if 2 oils are pigeonholed into a given grade/classification, it doesn't make them equal!

Exactly, nor are they necessarily interchangeable, either. However, if the grade and the specifications are identical, the two oils will likely be more similar to each other than different. There are few differences between various 5w-30 SN/GF-5 A5/B5 oils on the shelf in viscosity, and they are interchangeable in service.
 
i happened to talk to a co-worker at a company event, we happened to be sitting at the same table and i knew he was a chemist or something ... he plays soccer/softball with us once in a while.
anyways we were talking about school, etc. and found out he has a PHD in chemical engineer i.e. he is not an internet "expert" ... lol

i asked him about this topic and he said that my logic is correct.
some oil can pass 10W but barely miss the 5W test and are labled 10W and some oil may barely make the 10W.
the difference between these oil are almost a w grade. now i used 4.98W difference in my example (7.49 minus 2.51 = 4.98W).
he said that my point as far as the 2 oil (labled same xW) and being almost a W grade apart is valid but some people may focus too much
on my example of 7.49W and 2.51W since those specs don't exist.

he liked my grade analogy better ... that in order to get an A you need at least 90 and if you get 89 you get a B
and also you could barely pass the B standard by getting 80. there is difference between the 2 B's (89 minus 80 = 9 almost a grade)

he said that in general there may not really be that much difference between 0W and 5W and can have a 5W very close
to 0W and also said that the flow between the above oils may be very similar if it can be pumped or something to that effect ...

but this is where it get interesting (at least for me) ...
he said that some 0W oils can be thicker than a 5W of the same grade except at very low temperatures ...

i need to corner him again about the above statement since it initially confused me but I can now picture how it can happen. it raised another question for me regarding the graphs and linearity etc. which i may ask in another thread.
 
Originally Posted By: OilUzer
but this is where it get interesting (at least for me) ...
he said that some 0W oils can be thicker than a 5W of the same grade except at very low temperatures ...

i need to corner him again about the above statement since it initially confused me but I can now picture how it can happen. it raised another question for me regarding the graphs and linearity etc. which i may ask in another thread.


0W 40 will be typically thicker than a 5W20...except at the limits of pumpability.

Yes, an oil that narrowly misses 0W would have to be labelled as a 5W...the oils HAVE to be labelled the lowest grade that they meet.

If they don't make 0W, they can't be labelled that, and will never be labelled 2.5W, in spite of how fuzzy it makes you and your chemist friend feel.
 
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