Algorithm for rating oils...

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Jun 20, 2004
..from the Motor Oil Bible. VI + Flashpoint(F)+ 20(HT/HS)+ 2(TBN)- Pour point(F)- 3(NOAK)= Oil Rating (higher = better) There are ratings for mostly SL/SJ oils on the site to spring 2003 in the appendix. If this has been discussed before I couldn't find it in a search. Opinions and comments? Advantage to have a higher VI#?
Interesting. Nice if you can get the data, but I have one major objection, the VI term. A high viscosity index is good in a oil like Redline where there are no VIIs, but a high VI in a 10w40 conventional represents a lot of viscosity index improvers, which is not so good. Perhaps the term should be base oil group instead of VI.
TP, Are not VII and FM's used in todays conventional and synthetic oils sometimes similar to the esters you applaud? I think formulaters are utilizing additives that can perform more than one function and in many cases these adds are boosting the VI of the oils, acting as friction modifiers and providing boundary protection. At least that is what I have picked up in many of the writings here and elsewhere.
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