Someone correct me if I'm wrong, but I've read on here that GC doesn't contain VI's (viscosity improvers). It supposedly has the multi-viscosity naturally. I've been under the impression that the more VI's in an oil (typically the higher the "spread" in numbers), the less shear stable it is. So if the above assumptions are correct, then GC would be extremely shear resistant, and thus an excellent oil for higher rpm's (where shear occurs).
I am currently 600 miles in to my first OCI with GC in my '97 Maxima. Will get a UOA at 3000, and go from there. But so far, I am liking this oil for its "smoothness" at idle, and quieting down my engine (as compared to Mobil 1 5w30). And living in Louisiana with 100+*F weather typical in summer, I'll have no concern about GC's ability to handle the heat.
What do you consider "cruising" speed? For comparisons, my '97 Maxima is at 2400 rpm at 70 mph on flat interstate.
I would like some of the experts to chime in on my assumptions in the first paragraph. Information is power.
Dave