This is actually an interesting oil.
ACEA C5 oils tend to be low-VI oils, as opposed to Japanese-OEM oils, which tend to be ultra-high-VI oils, as wear protection (thick base oil) is the priority for the former and fuel economy (lower viscosity in a wider range of temperature and a wider range of temporary shear) for the latter.
Therefore, I ran my calculator to have an idea of what is going on.>> Estimated base-oil viscosity @ 150 °C (BO DV150) and VII content of selected oils <<
It went nicely right above the TGMO 0W-20.
It turns out that this oil actually has only a moderate amount of VII content
, and the ultra-high viscosity index (VI) is thanks to the very high VI of the base oil
, which must be a Group III+ or Group III++ etc. base oil, as the MSDS shows an almost entirely Group III(+ etc.) base oil. Moreover, the way the definition of the VI works is that for thinner oils the VII increases the VI a lot more than for thicker oils
. This is because the VII typically multiplies the KV40 and KV100 approximately by the same number. As a result you need less VII to make a 0W-20 with VI = 220 than, say a 5W-30
or less VII to make a 0W-20 than a 5W-30 of the same VI in general. This is another strength of thinner oils.
The base oil is still on the thin side for a 0W-20, but not as thin as what would be expected from the ultra-high VI.
It may probably use a small amount of ester as well, as they mention polar molecules for cleaning.