The whole point of HTHS is that it
is the fundamental correlant to film strength in real operation. HTHS viscosity is the primary characteristic that enables hydrodynamic separation and it is at the point of hydrodynamic breakdown that AW additives come into play. For example, from here:
http://books.google.com/books?id=g3v3MXz...ucUIuoavw&hl=en
Quote:
In one test...the engine goes from idle to nearly full throttle 20,000 times within one minute. Wear on the pinion pins of the planetary gears showed differing amounts of wear depending on the HTHS viscosities of the ATFs that all contained the same additive package. The pins rotate between boundary and hydrodynamic lubrication. Greater film strength may permit the pins to spend a greater fraction of their time in the hydrodynamic mode, leading to less wear.
Another quote specifically linking wear resistance to a kinematic/HTHS viscosity ratio similar to the one we're discussing here can be found in this document:
http://www.freepatentsonline.com/y2005/0221998.html
Quote:
The present inventors have performed extensive research in order to realize the aforementioned objective. As a result of this research, it was found that even when the viscosity, especially the HTHS 150° C. viscosity of an engine oil composition is further reduced, e.g., to less than 2.6 mPa.s or less than 2.4 mPa.s, if the ratio of the kinematic viscosity at 100° C. (hereafter referred to as “100° C. kinematic viscosity” or “KV100”) and the HTHS 100° C. viscosity (KV100/HTHS100) is held below a specific level, good abrasion resistance under conditions of high temperature and high shear rate can be guaranteed for the aforementioned sliding parts in the engine.
The subtext in the HTHS/kinematic viscosity debate is that kinematic viscosity can be "cheated" through the use of VII polymers and that HTHS is a far more reliable indicator of real-world viscous (hydrodynamic) performance. Look for example at Table 1 towards the bottom of the second link, above. It shows the expected correlation between base oil viscosity, HTHS, VII content, and wear. The more VII in an oil of a given kinematic viscosity at operating temperature, the lower the viscosity of the base oil and the lower, consequently, the HTHS; and the higher the wear.
As Red Line does not use VIIs in most of their street oils the "cheater effect" those VIIs represent does not exist to begin with, and therefore their correlated HTHS numbers would be higher
even if they used the same base stocks as other oils. Their actual HTHS values are higher still, implying strongly IMO that their base stocks do indeed have superior properties, which should directly correlate to less wear
or the ability to use a lighter grade.
The only way to avoid that logical conclusion in my humble opinion is to question the HTHS numbers themselves, which in the absence of evidence strikes me as an attempt to grasp at straws to maintain the belief that the product is in fact not as good as it and its users claim.
