Group III too thin for anything but 0wXX and 5wXX?

[G-MAN]

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Originally posted by dickwells: Interesting article in new "lubes & Greases" I quote from article titled Rising tide, "group III base oils set to surge" "For starters they are too lightweight for medium and heavy grade motor oils. "You can't even make a 10W-30 or 15W-40 using most currently available Group IIIs, You need a substantial portion of heavier GroupII or Group I in the mix." However, Group IIIs do work well in increasingly popular 5W motor oils and are the only alternative to poly alpholefins on 0W oil." I think a lightbulb just went off.

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This was quoted in another thread, but I thought it deserved its own discussion. If what this article says is ture, it begs the question: What are the Castrol Syntec 10w30, 10w40, and 20w50 grades made with? They are are supposedly Group III oils. Are they Group III, and the esters that are also used heavy enough to get the hi temp vis up where it needs to be for these oils? Hmmm...

 

[RB Shannon]

Here's a quote from Lubes and Greases April 0/3 "The vast majority of the 15w40 and 10w40 heavy duty motor oil in the US is made from Group II now.....In Europe,they are using Group I for 15w,and blends of Group I and Group III for 10w.The EuroIV low sulfer requirements will exclude the use of Group I base oils.What will be used for European 15w and 10w grades in the future?Group III oils are not the answer because these naturally tend to make 5w's-their J300 cold cranks are too low for 15w,and in most cases 10w engine oils" I'm wondering if their not referring to the VI of the base stock going to low to stay in spec and not necessarily being to light to be a SAE 40,but it's neat all the blending that goes on to get a usable base stock,so I would think i'ts unlikly that it's a pure Group III. another interesting note is Mobil's Core 145 Group I+ VI 105, NOACK 15%,and a pour point of -15C,and it infer's that they are working on a Group III+ also

 

[Dr. T]

The jist I get is you can't make 10 or 15 weights with group III's alone. But, if these synth's mixed group II's, it would be have to be called a "blend". In either case, does the article say why? Are these "too" refined to be made thicker? Question for 'cule then becomes....can esters be added to obtain higher viscosities? Or do esters automatically lower the viscosity of an oil ie. give it a lower PP??? ie. Can't a higher molecular weight ester be added or engineered to obtain a desired viscosity range?

 

[Jay]

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"You can't even make a 10W-30 or 15W-40 using most currently available Group IIIs, You need a substantial portion of heavier GroupII or Group I in the mix." However, Group IIIs do work well in increasingly popular 5W motor oils and are the only alternative to poly alpholefins on 0W oil."

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I'm confused by this statement. The author doesn't seem to understand that 5w is a more stringent cold temperature designation than 10W and 15W. It would make much more sense if he said, "You can't make a 0w with group I or II in the mix." That makes sense. The author has it assbackwards. Of course you can make heavier weight oils with group III. Shell's Rotella T Synthetic is one example.

 

[RB Shannon]

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The jist I get is you can't make 10 or 15 weights with group III's alone. But, if these synth's mixed group II's, it would be have to be called a "blend". In either case, does the article say why? Are these "too" refined to be made thicker?

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The word "blend" is probably just marketing,I don't think I've ever seen a requirment for a blend. I don't think they are to refined to be thicker( Group III) but have the ability to go down to the 5W spec easily,lower than the 15w in which their is still a market for. I'm wondering,They can probably blend the various group basestocks as long as they stay within spec of the API catagory. Sulfer Saturates VI Group I >.o3% <90% 80-120 Group II <.03% >90% 80-120 Group III <.03% >90% >120 Group IV ALL PAO's Group V All others not included in Group I-IV