Non linearity in mixing VIIs

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http://www.iasj.net/iasj?func=fulltext&aId=81553
Quote:
Influence of Some Additives on the Efficiency of Viscosity Index Improver for Base Lubricating Oils Prof. Dr. Talib Bahjat Kashmoula Tiba Naif Jasim E-mail: [email protected] Chemical Engineering Department, Collage of Engineering, Alnahrain University, Baghdad, Iraq ABSTRACT The effects of three different additives formulations namely Lubrizol 21001, HiTEC 8722B and HiTEC 340 on the efficiency of VII namely OCP of three base lubricating oils namely 40 stock and 60 stock and 150 stock at four temperatures 40, 60, 80 and 100oC were investigated. The efficiency of OCP is decreased when blended with 4 and 8 wt% of Lubrizol 21001 for all the three base oil types. But it is increased when adding 4 wt% and 8 wt% of H-8722B in 40 stock. While for 60 stock and 150 stock the OCP efficiency decreased by adding 4 and 8 wt% of H-8722B. In the other hand, it is decreased with a high percentage by adding 4 and 8 wt% of H-340 for 60 stock and 150 stock and for 40 stock it is increased by adding 4 wt% of H-340 and decreased with insignificant percentage when adding 8 wt%. Finally, a number of VI correlations have been obtained depending on the results predicted in this study. These correlations represent the functional relationships between the VI and the concentration of OCP for three types of base lubricating oil and for each type of additives.
Somewhat interesting, when read in conjunction with JAG's find a while ago that OCP are much more shear stable than some of the others http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1171968
 
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The weakness of the paper echos the weakness of the VI specification temperature spread. Who cares what one lubricant does better than the next between 40C and 100C? I stopped looking at VI a long time ago when I discovered that a high VI number usually hurt HTHS in engine oils. For me at least, VI is not a selling point.
 

Shannow

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I still look at VI when checking out what's out there. I just discount the unicorn end VIs as too much of a compromise on the functional aspects of an oil. 10% VII versus a couple of percent is a big difference.
 
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10W3.6 VI exists somewhere between those two important specs. (10W30) 5W3.4 ; The quest for a higher VI hurt HTHS in this case. (5W30) VI will likely drop with SAE XW16 engine oils to maintain HTHS. I've decided that if I need a 0Wxx, I'm staying indoors anyway.
 

MolaKule

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If one uses the right mix of base oil viscosity types or one of the non-VII polymers in the mix one won't need a methylacrylate or OCP VII polymer.
 
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3,379
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BC, Canada
I think so, but it would be interesting to plot heart rate vs body temperature. Maybe you are on to something here. Instead of working out, walking, swimming etc, save your time and energy and shiver those pounds away.
 
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