Originally Posted by kschachn
And as SonofJoe pointed out on here not all VII are the same. Some are of higher quality than others and are more shear resistant. He also stated that higher quality ones are more resistant to permanent viscosity loss.
I have read similar outside of BITOG. That a VII with a low shear stability index - "SSI" (the lower the number the better) is of premium quality (and expensive). Without knowing the base oil(s) viscosity it's impossible to know the quality and how much they're contributing to the finished lubes VI. Unless I'm missing something, and it's quite possible that I am, I just don't see how you can glean much about the lubes VII's from either a VOA or UOA.
Maybe you could make some loose and broad assumptions by noticing permanent shear from the UOA?🤔...dunno..but still, can you definitively attribute that shearing to the quality of the VM or is/was it a result of something else??
And as SonofJoe pointed out on here not all VII are the same. Some are of higher quality than others and are more shear resistant. He also stated that higher quality ones are more resistant to permanent viscosity loss.
I have read similar outside of BITOG. That a VII with a low shear stability index - "SSI" (the lower the number the better) is of premium quality (and expensive). Without knowing the base oil(s) viscosity it's impossible to know the quality and how much they're contributing to the finished lubes VI. Unless I'm missing something, and it's quite possible that I am, I just don't see how you can glean much about the lubes VII's from either a VOA or UOA.
Maybe you could make some loose and broad assumptions by noticing permanent shear from the UOA?🤔...dunno..but still, can you definitively attribute that shearing to the quality of the VM or is/was it a result of something else??
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