JB,
I think the difference in oils is the addative package that is put into
the oils. I work for ExxonMobil and we make the "Next Generation" of oils
to be used to meet the 2006 EPA guidelines, but I won't claim to know a lot
about oils, but I have done some looking around.
As somebody said a few posts back, " most oils are made by adding a additive
package to a "base" stock". This base stock can be the same for Shell,
Exxon, Quacker State or whoever, it just has to meet or exceed a set of
parameters. The specific oil company will then add their special "additive"
package which includes detergents, friction fighters, zinc (ZDP) or
whatever. There are a million different formulas made up of thousands of
additives. Because of this, some might actually be better than others. Or
some can be better for specific applications than others, due to the
specific level of additive.
The problem is in getting the manufacturers to tell you what is in the
addative packages. Last year I contacted several oil companys inquiring the
levels of zinc or ZDP in their oils. Some would tell me the amount, others
would not.
Here is a link to a oil comparasion, it was for motorcycles but some good
info included.....
http://www.ibmwr.org/otech/oilreport.html
Here is another, sorry it is more geared toward motorcycle oils.....
http://www.xs11.com/stories/mcnoil94.htm
Hope this was helpful,
Regards, Tom
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