Just a question cause I need to be informed. The CCS numbers are low. Would that indicate less VII?
To me the opposite, but I'm just guessing here.
Many modern resource conserving oils, ILSAC & dexos1, seem to be going for the lower end of the winter (W) grade, to perform better on the standard fuel economy tests. So it seems.
One way to do this is to use more thin base stock to lower the CCS numbers, then add more VII to up the KV100 viscosity in compensation. But again, more of a simple guess, in a complex field.
Recall many of the affordable full synthetic oils now days are made on Group III, as PAO is more expensive. But Group III base stock mostly comes as 4, 6 and 8 cSt, meaning a G-III 5W30 with a KV100 of 10 cSt needs VII to make it a 30 grade oil. Now a G-III 5W20 would be a very nice oil, except this seems to be falling out of fashion, with 0W20 being the preferred grade. Back to the same issue.
Here is a typical list of Group III base stock out of Vertex / Penthol Texas.
Viscosity at 100C: 4.24, 5.84, 7.87 cSt.
Viscosity at 40C: 18.92, 30.41, 47.25 cSt.
Viscosity Index: 132, 139, 136 VI.
Flash Point: 230, 238, 270 C.
Pour Point: -25, -23, -21 C.
CCS at -30C: 1168, 3118, 6795 cP. (note all at the same temperature)
Noack: 13.7, 7.5, 2.3 %
So as you lower the CCS you are also dropping the KV100 but raising the Noack volatility. As
@OilUzer said above, low Noack is the figure to look for.
Ref (G-III and G-II for comparison):