Yep but the SAE designations are grades. Ranges of viscosities.
viscosity charts
- Thread starter tomfiii
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Look at SAE J300, which will simply tell you want grade the oil is. It's very unclear what you're looking for.
Way too general and unspecific description of what you're looking for.
What oil?
A much thinner oil than a xW-50 grade would have to be a colder than 100C (212F) - the KV100 viscosity - to be a 50 grade at full engine operating temperature. You running an ice cooled oil cooler, lol ?? Still not sure exactly what you're trying to compare or find.
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Each brand of 20W50 will be a bit different.
This will help. We use this every day.
David
David
That's only one "decoder" he would need. He also needs 1) the KV40 and KV100 of the specific oil he's talking about, and 2) Widman's viscosity vs temperature calculator tool. Then pick the viscosity off the graph at whatever temperature(s), then use J300 to determine which "SAE viscosity grade" it is. At least that's the best I can discern from this convoluted thread.
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OK, so look at J300 like HPL posted, the range for an SAE50 at 100C is 16.3 to 19.5cSt.
Let's use the Widman mixing calc:
https://www.widman.biz/English/Calculators/Mixtures.html
And the Widman operating viscosity calc:
https://www.widman.biz/English/Calculators/Operational.html
Let's start with the 2nd one, you said 140F, which is 60C. That's pretty cold. An oil that's in the SAE 20 range at 100C, between 6.9 and 8.5cSt is up in the SAE 70 range at that temperature.
Just dropping the figure down to get into our target, if I use 4cSt @ 100C, I get 18.7cSt at 60C/140F. There's nothing you can add to 20w-50 that is going to make it that thin unless you are mixing it with diesel or gasoline, that's the bottom of the 0w-8 designation.
So we don't even need to use the mixing calc, because that's not going to help.
Double
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0W-16
36 @ 40C
7 @ 100C
18.36 @ 60C (140F)
16.3 to < 21.9 at 100C (212F) = SAE 50 Grade
Note: All ViscositIes in cSt.
36 @ 40C
7 @ 100C
18.36 @ 60C (140F)
16.3 to < 21.9 at 100C (212F) = SAE 50 Grade
Note: All ViscositIes in cSt.
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Wow, I didn't even come to the conclusion that he was trying to mix viscosity to come up with some frankenbrew ... see how convoluted this all is.
I didn’t either and I’m still not sure that’s the point here.Wow, I didn't even come to the conclusion that he was trying to mix viscosity to come up with some frankenbrew ... see how convoluted this all is.
The grade is the grade no matter what temperature it is at. It will be a 20W-50 if it is -273C or 10,000C. The viscosity at set temperatures is what determines the SAE grade. No grade ever changes to another grade depending on temperature.
Wrong , as temperature climbs it meets the requirements of a higher grade oil. As at what temperature would a 20w-50 oil be at 40 grade as it can't be at 20 ,30,40,50 at the same temperature.
What is so hard about a simple answer to the question ,I'm not trying to invent the wheel. As the temp. climbs the multi grade oil is supposed to meet the requirement of the next grade of oil as not to thin out. I have a condition in a vehicle of the oil running at lower temperatures and i am worried that a multi grade such as 20w-50 won't be the same as a straight 50 weight oil at that temperature.
Well there you go. He solved the problem. Turn out the lights when you leave.
I am not trying to get oil thinner. What I want to know is if the oil only gets to 140 degrees at what grade is the 20w-50 oil at that point . You buy oil in a certain grade not cSt at the parts store.
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