Wondering about the esters used in High Mileage oils...

[G-MAN]

I've been wondering, are the esters used in HM oils "base oil" esters or "additive" esters? In other words, is the ester content of HM oils derived from the base oil blend (a mix of Group V and Group II), or are these esters strictly performance additives that are part of the add pack with the base oil blend being just Group II?

I'm sure a base oil ester could pull double duty and be good for seals as well (which is the case with PAO-based synthetics.) Or the esters in the HM oils could just be additives. Anyone know for sure?

 

[Bror Jace]

G-Man II, I guess I just don't distinguish between an ester which is added in as part of base oil versus one which is considered an additive.

And I bet the esters used in these high-mileage formulas are a fairly common and inexpensive one ... maybe a cheaper dibasic ester?

--- Bror Jace

 

[MolaKule]

The most likely scenario is that the esters are of two sources:

1. Additves - most additive today, including PAMA viscosity modifiers, are esterified, because they can be used for both synth and dino oils. Additives in ester formats are more soluble in all oils and can be better concentrated for large batch mixing.

2. Friction Modifiers - specialty esters of high molecular weight, that are readily soluble in any oil, act as friction Modifiers.

I do distinguish between additive esters and base oil esters.

Most base oil esters are synthesized diesters and synthesized or natural esters comprising 10% to 40% of the PAO/ester base oil combination.

Additive esters might comprize 5% total at the most. The highest percentages of additives are the detergent/dispersants. For dino and synthetic oils having high weight-swing (viscosity range), the viscosity index improvers are nest higest in terms of additive concentration.

 

[Bror Jace]

'Kule, given the modest $2.00 - $2.50 price per quart, I assumed that the ester content of the high mileage oils was of the base oil type. Nothing fancy-shmancy as that would be too expensive.

From what has been said here, I thought the content of these oils varied from about 10-15% ester.

When originally reading G-Man II's question, I had not considered something exotic like a borate-ester or other ester-based fritction modifier.

--- Bror Jace

 

[MolaKule]

TallPaul,

It is related to the latter:

quote:

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...or it is correlated with the ratio of VI-improved viscosity to the non-VI-improved viscosity?

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[MolaKule]

quote:

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high weight-swing (viscosity range),

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Sorry about that. But I used both terms trying to convey the thought of wide viscosity variations.

A better phrase might have been, "wide weight-swing (viscosity index range)."


Kinda like "eminent" and "imminent."

 

[TallPaul]

quote:

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Originally posted by MolaKule:
For dino and synthetic oils having high weight-swing (viscosity range), the viscosity index improvers are nest higest in terms of additive concentration.

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MolaKule: When considering weight-swing (interesting term, never heard it before) is the magnitude of VII additive correlated with the absolute difference in viscosity, or it is correlated with the ratio of VI-improved viscosity to the non-VI-improved viscosity?

For example A 5w30 and 15w40 both have the same apparent spread, though they could differ depending on actual 100C cSt viscosities. But lets say their absolute viscosity ranges are the same. So for the 5w30 we have the base oil at 4 cSt and the VI-improved at 11. For the 15w40 we have the base oil at 6 cSt and the VI-improved at 13. In both cases the absolute viscosity range is 7 cSt, but the ratio of the improved to the unimproved is 2.75 for the 5w30 and only 2.17 for the 15w40. And so by the weighted case the 15w40 would have less VIIs than the 5w40 in my examples.