Sorry Sorry, looks like I am a little late.... Silkolene has newer 10W-50 weight Pro-4 Plus out. It's a full 100% Ester Synthetic which is what you want by all accounts. It's The Ester Base Stock that is important...
Lubricant Characteristics
Engine oils have changed considerably over the last ten years. A major advance is greater availability of new, more highly refined base-stocks that significantly enhance lubricant performance under more demanding operating requirements. The American Petroleum Institute (API) identified five base oil categories (Table 1) that are used with the API Base Oil Interchange Guidelines to help assure that engine oil performance is not affected adversely when one basestock is substituted for another in a finished oil formulation.
Historically, refiners made basestock by solvent refining and dewaxing selected crude oil fractions (Group I). With the development of hydrotreating and hydrocracking technology, refiners introduced highly refined, low aromatics, low wax basestocks with improved oxidation stability in large volume (Group II).
More recently, higher viscosity index basestocks made by high severity hydrocracking of petroleum fractions have become available (Group III). Group III stocks differ from Group II products in the structure of the lube oil molecules that impart the higher viscosity index. Group III basestocks are limited to lower viscosities, typically, 4 to 7 cSt at 100°C.
API identified polyalphaolefins (PAOs) as a special class of basestock. PAOs are made by a chemical process and have the characteristics of uniform composition, very high oxidation stability, high viscosity index and no waxy molecules. By adjusting the manufacturing process, PAOs can be made in a wide range of viscosities, commonly from 4 cSt to 100 cSt at 100°C. For many years, PAOs and esters (Group V) were the only available premium basestocks for engine lubricants operating under extreme temperature and conditions.
Most synthetic engine oils made with PAO now contain a small amount of ester to give the basestock the same solvency power as typical mineral oils. This helps to assure that the synthetic lubricant will have the same seal swell characteristics as conventional oils.
Table 2 lists some typical properties of Group I through Group IV basestocks with similar viscosities at 100°C.
Click here to see Tables 2 and 3
Critical base oil properties improve from Group I to Group IV. Also, less viscosity index improver (polymer) is required in multigrade engine oils with the higher VI basestocks. This leads to improved shear stability (Stay-In-Grade) and fewer deposits from polymer degradation.
Basestocks that have been severely hydrogenated to remove almost all aromatics (Group II and III) and chemically manufactured, 100 percent paraffinic PAOs (Group IV) have an added advantage in boosting the performance of dispersants in the additive package of fully formulated oils to hold soot in finely divided suspension in the oil. Soot forms in engine lubricating oil when fuel is not completely burned. If the soot is not properly dispersed, viscosity increase due to soot thickening can shorten the useful life of the oil. Also, soot particles can clump together and form deposits in critical parts of the engine. 1
The main barrier to using better performing Group III and Group IV basestocks is cost, Table 3. Group IV (PAO) basestocks used in conjunction with esters (Group V) are more expensive than other basestocks derived from crude oil. The decision to use engine oils made with PAO/ester blends has to be based on a cost/benefit analysis to justify the higher price of the lubricant against the anticipated benefits.
Definition of Synthetic Lubricants - Buyer Beware
For many years, PAOs and other chemically synthesized basestocks were the only lubricant products that could be advertised as synthetic. The National Advertising Division of the Better Business Bureau broadened the definition of synthetic lubricants to include products made with Group III basestocks in a 1999 ruling. This created confusion in the marketplace as to what the customer was actually buying when he specified “synthetic motor oil.†2
Some lubricant marketers also promote semisynthetic engine oils that are a blend of synthetic basestock and conventional mineral oils. Semisynthetic engine oils could have as little as 10 to 20 percent synthetic in the formulation. These products can be purchased at a lower cost than full synthetics. Performance features, especially with respect to low temperature flow, high temperature evaporative loss and oxidation stability, are generally inferior to full synthetics, although they may be perfectly adequate for many applications. There is no requirement for oil marketers to specify the amount of synthetic basestock in finished semisynthetic oil, or to state whether the synthetic component is a Group III or Group IV base oil.
The point here is to be sure that the performance features are understood when purchasing a synthetic engine oil. Ask the oil marketer for product data sheets, test results, especially data that shows lubricant performance under stressed conditions, and field test reports in equipment that is relevant for your operations.
So, like anything else you are going to get what you pay for, I've wrestled with this in my head for awhile, and yes, a Liter of FULL ESTER Silkolene will run you about $12. But in My mind I am comforted by knowing that I have the absolute shiznit in my crankcase. I'll run the cheaper stuff in the Infiniti, but not the Busa, I work it far to hard to cut any corners...
Some more information:
This is sort of a
Maxima Propaganda page but the First Two Pages have relevant information...
Anyhoo, Point is you get what you pay for if you do your Home work....
