With all the hoopla about high VI being the holy grail of engine oils i found this interesting.
When one poster claims TGMO to be the best because it has higher VI than say Mobil 1 or PP/PU it seems he may be ignoring the effects of the base stock.
Quote:
Viscosity Index/Improver Additives
Viscosity Index (VI) is the term used to rate a base oil or an oil products ability to resist thickening and thinning with temperature change. These VI improvers are typically thin straight polymers, or polymers that “unwind” and straighten out at higher temperatures. This helps to maintain a more consistent viscosity of a wider range of temperatures. But, typical VI improving additives are far more fragile than the base oil and are easily sheared in half under a variety of operating conditions. HD diesel applications use VI improvers that are more durable. And, higher grade base stocks have less need for VI improvers. Some top tier synthetic oil products meet SAE 5W-30 ratings without any VI improvers.
http://www.diagnosticnews.com/oil-additives-supplements/
When one poster claims TGMO to be the best because it has higher VI than say Mobil 1 or PP/PU it seems he may be ignoring the effects of the base stock.
Quote:
Viscosity Index/Improver Additives
Viscosity Index (VI) is the term used to rate a base oil or an oil products ability to resist thickening and thinning with temperature change. These VI improvers are typically thin straight polymers, or polymers that “unwind” and straighten out at higher temperatures. This helps to maintain a more consistent viscosity of a wider range of temperatures. But, typical VI improving additives are far more fragile than the base oil and are easily sheared in half under a variety of operating conditions. HD diesel applications use VI improvers that are more durable. And, higher grade base stocks have less need for VI improvers. Some top tier synthetic oil products meet SAE 5W-30 ratings without any VI improvers.
http://www.diagnosticnews.com/oil-additives-supplements/