Thanks Jag! Two oils I'm considering in my VW is the new Mobil 1 High Mileage 10w30 and 10w-40. The 30w is an A3 rated oil and I bet it doesn't have many VII's. The 40w looks good as well with an HTHS of 4 and higher flash point compared to the Mobil 1 Turbo Diesel Truck.
Polymeric Viscosity Index Improvers and Deposits
- Thread starter JAG
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Is Shells VI improver better than others? Is Pennzoil more stable than other dinos? A few years back I read Pennzoil was made with "the new Shell VI improver".
Is Havoline Deposit Shield the new shear stable king of dinos?
Old thread with two new additions. From ILSAC GF-5 information:
http://www.gf-5.com/the_story/ingredients/
Quote:
Viscosity modifying additives (VM) control the temperature-viscosity relationship of engine oils. Viscosity modifiers are susceptible to shear degradation in the engine. Viscosity modifiers with good fuel economy and high temperature deposit performance will be needed to meet the requirements of GF-5.
From a Mobil patent: http://www.freepatentsonline.com/6713438.html
Quote:
The use of high molecular weight thickeners and VI improvers in the production of multi-grade lubricants has, however, some serious drawbacks. First, these improvements are more sensitive to oxidation than the basestocks in which they are used, which may result in a progressive loss of viscosity index and thickening power with use and frequently in the formation of unwanted deposits. In addition, these materials tend to be sensitive to high shear rates and stresses as well as to a high degree of temporary shear the result of which is that temporary or permanent viscosity losses, or reduction of film thickness in bearings may occur. Temporary viscosity losses occurring from shear forces are the result of the non-Newtonian viscometrics associated with the solutions of high molecular weight polymers. As the polymer chains align with the shear field under high shear rates, a decrease in viscosity occurs, reducing film thickness and the wear protection associated with the elastohydrodynamic film. By contrast, Newtonian fluids maintain their viscosity regardless of shear rate. From the point of view of lubricant performance at high temperatures and under the influence of a shear rate condition, it would be desirable to maintain Newtonian rheological properties for the lubricant.
http://www.gf-5.com/the_story/ingredients/
Quote:
Viscosity modifying additives (VM) control the temperature-viscosity relationship of engine oils. Viscosity modifiers are susceptible to shear degradation in the engine. Viscosity modifiers with good fuel economy and high temperature deposit performance will be needed to meet the requirements of GF-5.
From a Mobil patent: http://www.freepatentsonline.com/6713438.html
Quote:
The use of high molecular weight thickeners and VI improvers in the production of multi-grade lubricants has, however, some serious drawbacks. First, these improvements are more sensitive to oxidation than the basestocks in which they are used, which may result in a progressive loss of viscosity index and thickening power with use and frequently in the formation of unwanted deposits. In addition, these materials tend to be sensitive to high shear rates and stresses as well as to a high degree of temporary shear the result of which is that temporary or permanent viscosity losses, or reduction of film thickness in bearings may occur. Temporary viscosity losses occurring from shear forces are the result of the non-Newtonian viscometrics associated with the solutions of high molecular weight polymers. As the polymer chains align with the shear field under high shear rates, a decrease in viscosity occurs, reducing film thickness and the wear protection associated with the elastohydrodynamic film. By contrast, Newtonian fluids maintain their viscosity regardless of shear rate. From the point of view of lubricant performance at high temperatures and under the influence of a shear rate condition, it would be desirable to maintain Newtonian rheological properties for the lubricant.
I noticed that the PDS states for Mobil 1 0w-40 that it helps "clean deposits". Some have said this oil has a good ester content. What JAG posted is correct though. With synthetics, you are generally not looking at too much VII's. Obviously the larger the spread, the more VII's. Redline uses none which is nice.
VII's are a double edge sword it seems.
VII's are a double edge sword it seems.
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