Group II and III oils without any "polar content"

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I've thought about this before, and I can't think of any. It must have something to do with the % and type of ester. Pretty much all oils have ZDDP in them, which comes in an ester.
 

moribundman

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 Originally Posted By: chevrofreak
Pretty much all oils have ZDDP in them, which comes in an ester.
Which one don't? I'll give you a hint: it's those oils that work best with A-Rx. Which oils are those?
 

moribundman

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So there are no current engine oils that are suitable for fully taking advantage of A-Rx? Even I find that hard to believe. What oils are people's favorites then when using A-Rx? Let's have a look!
 
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with all the reformulations over the past few years it is hard to know, or keep up. Offering would be at best guesses for the most part.
 

moribundman

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So how do you pick an oil that will make the best of A-Rx, if you just can't possibly know what's in the oil?
 
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There are virtually no polar compounds (sulphur /nitrogen) in a hydroprocessed Group II/III base oil. Although, the different hydrocarbon structure of the molecules in Group II, III, PAO can have differences in polarity. This zddplus.pdf article discusses polarity.
 
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Law of averages maybe? That RaceTrac oil was commenting on in another thread may be a good bet. Who is still using GI carriers for the add packages these days? A good number of the base products in product lineups would I bet. Chevron Supreme blue bottle, Valvoline white bottle, Mystik fleet oils, Supertech oils, these would be a few I might start with.
 

moribundman

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 Originally Posted By: Drivebelt
There are virtually no polar compounds (sulphur /nitrogen) in a hydroprocessed Group II/III base oil. Although, the different hydrocarbon structure of the molecules in Group II, III, PAO can have differences in polarity. This zddplus.pdf article discusses plarity.
If ZDDP is highly polar, how does hydroprocessed Group II/III base oil contain "virtually no polar compounds"?
 

moribundman

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 Originally Posted By: jmac
"Base" oil has no additives yet, including ZDDP.
That's irrelevant, because you do not buy a base oil. You buy a ready-to-use consumer product.
 

JHZR2

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Surface chemistry dictates the nature and energetics (which is the main driver for what goes on) of the interactions between molecules in the liquid phase and the top surface of the solid phase. The surface of the solid may not have the same properties as the bulk metal below it. Depending upon all of these things, and the nature of what is trying to interact will determine what happens. ZDDP may be polar, but self-assemble into structures which remain in solution (just a speculation, not the truth). The polar hydrocarbons may adsorb chemically onto the metallic surface, on the other hand (again, just speculation). Alternately, one molecule type may competitively interact with the surface in a stronger manner than another type. Since nature always wants to go to a low-energy state, one may be preferentially interacting with the surface to a far larger amount by a huge margin. So one polar molecule may be far different in its interaction with the set of surfaces in an engine than another...
 

moribundman

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 Originally Posted By: JHZR2
ZDDP may be polar
I belive the issue was less the polarity of ZDDP itself, but rather the fact that ZDDP comes in an ester:
 Quote:
Pretty much all oils have ZDDP in them, which comes in an ester.
 

JHZR2

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Right, but there may be more to the desired interaction set than the ester component of the zinc compound. If the zinc compound interacts with surface metal atoms, what is the nature of the interaction? Is the sulfur, zinc, phosphorous or hydrocarbon actually adsorbing to the surface? Sulfur can interact with metal surfaces to create a new phase or material with substantially different properties (one of the reasons, for example, that sulfur made a good lubricant in diesel was that it interacted with components in the alloy used in typical injection pumps. This alloy had a completely different character (hardness, melting point, etc.) than the bulk metal, and caused a wear reduction.
 
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