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AMSOIL 100% Synthetic normal, and RACING Motor oils, Lubricants.
Lubricant Base Stocks


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Top Quality Base Stocks are the key.

Someday soon, we won't have conventional basestocks to kick around anymore. Superior basestocks and stricter motor oil specifications are squeezing conventional basestocks out of the market. The next passenger car oil performance specification, International Lubricants Specification and Approval Committee (ILSAC) GF-3, looks as though it will have significantly tighter volatility limits than the current ILSAC GF-2 spec has, tighter limits than conventional basestocks can meet on their own.

In fact, Harts Lubricants World (Nov. 1997) writes that demands for greater thermal stability, oxidative stability and lower volatility coupled with higher standards for automatic transmission fluids, "will soon make Group I solvent-refined oils obsolete, unless they are blended with higher quality products or synthetics to correct their limitations."

While synthetic basestocks have been available for decades, and define the quality standard for basestock performance, hydroprocessed oils and their allies are relatively new. It is the appearance of these new, highly processed mineral oils that spells the end of conventional oil, or at least its dominance of the basestock market.

What Is a Conventional Basestock?

The American Petroleum Institute defines five groups of basestocks. Groups I, II and III are mineral oils classified by the amount of saturates and sulfur they contain and by their viscosity indices. Group I basestocks are solvent refined mineral oils. They contain the most saturates and sulfur and have the lowest viscosity indices. They define the bottom tier of lubricant performance. Group I stocks are the least expensive to produce, and they currently account for abut 75 percent of all basestocks. These comprise the bulk of the "conventional" basestocks.

Groups II and III are the High Viscosity Index and Very High Viscosity Index basestocks. They are hydroprocessed mineral oils. The Group III oils contain less saturates and sulfur than the Group II oils and have higher viscosity indices than the Group II oils do. Groups II and III stocks perform better than the Group I basestocks do, particularly in measures of thermal and oxidative stability. Isodewaxing oils also belong to Groups II and III. Isodewaxing rids these mineral oils of a significant portion of their waxes, which improves their cold temperature performance greatly. Groups II and III stocks are more expensive to produce than Group I stocks are, and account for about 20 percent of all basestocks. These are the stocks that are squeezing the Group I "conventional" stocks out of the marketplace.

Group II and III stocks may be "conventional" or "unconventional": these marketing terms have no precise definitions. Generally, unconventional basestocks are mineral oils with unusually high viscosity indices and unusually low volatilities. Group II and III solvent refined mineral basestocks are "conventional.'' However, one producer calls its Group II hydrocracked isodewaxed basestock "unconventional" while another calls its Group II hydrocracked isodewaxed basestock "conventional" - because that producer has a Group III oil for which it reserves the label, "unconventional."

What About Groups IV and V?

Group IV includes polyalphaolefins (PAOs). Group V includes all other basestocks not included in Groups I, II, III and IV. Esters are Group V basestocks.

According to Lubes 'N' Greases (Nov. 1997), if basestocks were arranged in a performance pyramid, the Group I stocks would comprise the base, Groups II and III the middle and Group IV the pinnacle of performance. Group IV stocks, the PAOs, make up about 3 percent of the base oil market. (The Group V basestocks do not figure in the pyramid, presumably, because of the group's diversity, its small market share and wide range of performance.)

Net Effect

The net effect of the changing marketplace is one of increasing lubricant quality. Compared to Group I solvent refined oils, hydroprocessed Group II and III oils offer lower volatility, and when properly additized, greater thermal and oxidative stability and lower pour points. Group IV oils offer superior volatility, thermal stability, oxidative stability and pour point characteristics to those of the Group II and III oils with less reliance on additives.

For consumers, that quality increase will bring oils with lower rates of oil consumption, longer drain capabilities and better performance in high and low temperature operations.

Even with an overall increase of motor oil quality as Group I stocks are phased out of the market, the differences between Group II and III oils and Group IV oils leaves a substantial margin for product differentiation.

"We [PAO manufacturers] design the desired molecular structure in advance, then manufacture to explicit specifications,'' Jim Willis, manager of Mobil Chemical's Beaumont, Texas facility told Lubes 'N' Greases (Nov. 1997). "And you have a base oil which is absolutely consistent from batch to batch and which provides certain performance properties - in low temperature starting and pumping (characteristics that a low pour point alone don't guarantee). Volatility, wear protection, improved fuel economy - that cannot be matched by base oil produced by either process, whether it's solvent refined or hydroprocessed."

The trend toward increasing motor oil quality will not be reversed. In fact, as environmental regulations grow increasingly strict, motor oil quality will have to increase even more. And while Group II and III basestocks provide better performance than Group I basestocks do, they have lower performance ceilings than Group IV stocks do. The future belongs to the Group IV basestocks (AMSOIL Synthetic Oils are Group IV Polyalphaolefins).

To learn more about AMSOIL Synthetic Oils which are produced with Group IV Polyalphaolefin basestocks.

Additives are important, but top quality basestocks are the key to a superior oil. AMSOIL Synthetic Oils give you the best of both worlds.

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