Originally Posted by wolf_06
The tendency for thin oils like 0w20, 0w16, 0w12 and 0w8 (which I dont think is even on the market) is more common now.
My Mazda 3 specs for 0w20.
Most 0w20 viscosity is around 8.6 at 100 degrees.
Is there any thinner 0w20? closer to a 0w16? Im curious about it.
Thanks!
While it might sound contrary to common sense, for a given HTHS, the higher the KV100, the thinner the oil is. Therefore, for a given HTHS, if you're looking for a thicker oil, choose the oil with the lowest KV100.
Why? This is because for a given HTHS, the higher the KV100, the more the VII content is, which means the thinner the base oil is. As a result the viscosity index will be higher and the HTHS at lower temperatures (lower than 150 °C) will be lower. Moreover, there will be more VII shear, and the HTHS will be lower at higher shear rates (higher than 1,000,000 1/second), like in the valvetrain.
Again, if you want a "thick" 0W-20, look for one with the lowest KV100 and highest HTHS, not for one with a high KV100.
An example is TGMO 0W-20. While it has KV100 ~ 9 cSt, it's the thinnest 0W-20 out there due to its very high VII content. The high VII content raises the KV100, but what matters is the dynamic viscosity under shear, which will be lower under more conditions thanks to the high VII content.