Rethinking the synthetic/VI improver issue

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I know I've posted on this forum with my surmizes that Mobil 1 0w30 and 0w40 may be the grades with the least VI improver added, with the wide viscosity spread coming primarily from the blend of high VI PAOs and esters in the base oil. Tonight, I decided to rethink that position while looking at the Red Line website. Briefly, here's why: Red Line oils use polyol ester basestocks which have naturally high inherent VIs and Red Line states plainly on their website that all their multi-weight grades are achieved without the use of VI improvers. But take a look at the VIs of the finished Red Line oils: they are lower than what you see in other finished synthetic oils of the same weight. Example: Red Line 10w30 has a VI of 137; Mobil 1 10w30 has a VI of 145; Amsoil 10w30 has a VI of 167. So, here's what I'm thinking: For Group IV/Group V synthetics, can the VI of the finished oil be and indicator of how much VI improver was used to obtain the viscosity spread, with a higher number indicating more VI improver and a lower number indicating less? My reasoning is based on the Red Line's VI being lower than both Mobil 1's and Amsoil's. The only Mobil 1 where Mobil states no VI improvers are used is the 20w50 motorcycle oil. The VI is 150. Red Line's 20w50 has a VI of 157. Amsoil's 20w50 has a VI of 160. Red Line's 10w40 has a VI of 159, while Amsoil's 10w40 has a VI of 183. So, once again it appears what we are seeing is that the oils with no VI improvers are the ones with lower VIs. (By comparison, one would assume Amsoil's straight 30wt synthetic would have no VI improvers, yet it has a VI of 124.) If you've followed my reasoning thus far, and applying it to the Mobil 1 line of oils, it would seem then that Mobil 1 10w30 could very well be the prime SuperSyn candidate for having NO VI improvers added. If the Mobil 1 20w50 has no VI improvers, and attains a 30wt spread with a VI of 150, then it seems reasonable to conclude that the 10w30, with a 20wt spread and a VI of 145 would be the other Mobil 1 with no VI improvers, especially in light of looking at the Red Line VI for the same weights. At any rate, I plan to call Mobil's tech line tomorrow and ask them directly which grades of the Mobil 1 have the least (or no) VI improvers.
 
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Good question. So would Mobil's 0w-30, 0w-40 being they have the least amount of VI's, hold there weight better and be less likely to thin out? [Confused]
 
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Isn't the VI simply based upon a change in viscosity over a given temperature change? So if someone developed a VI-improver free lube with a very low cold viscosity (compared to other oils) and an equally high (compared to other lubes) warm viscosity, this oil would have a very high VI. Because of this, i'm wary to follow your reasoning. Shouldn't ANY oil that has the same viscosity / temperature characteristics of a given sample, have the same VI? ferb!
 

G-MAN

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Originally posted by Ferb: Isn't the VI simply based upon a change in viscosity over a given temperature change? So if someone developed a VI-improver free lube with a very low cold viscosity (compared to other oils) and an equally high (compared to other lubes) warm viscosity, this oil would have a very high VI. Because of this, i'm wary to follow your reasoning. Shouldn't ANY oil that has the same viscosity / temperature characteristics of a given sample, have the same VI?
Viscosity index (VI) is a measure of how resistent an oil is to change in viscosity with temp change, with a higher VI oil having more resistence to change than one with a lower VI. My reasoning, therefore, is simply this: A synthetic oil with no VI improvers exhibits less resistence to change in viscosity with temp than one with VI improvers. The data I've referenced seems to bear this out.
 

G-MAN

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Originally posted by Ferb: So if someone developed a VI-improver free lube with a very low cold viscosity (compared to other oils) and an equally high (compared to other lubes) warm viscosity, this oil would have a very high VI.
What you've described is precisely what some of ExxonMobil's SuperSyn PAO base stocks are. They are very high viscosity base oils that have very high VIs. In other words, they are equally thick at both low and high temps, exhibiting very little change in viscosity with temp change.
 

G-MAN

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Originally posted by buster: Good question. So would Mobil's 0w-30, 0w-40 being they have the least amount of VI's, hold there weight better and be less likely to thin out? [Confused]
Actually, what I'm saying (if my reasoing in this thread is sound), is that Mobil 1 10w30 MAY have no VI improver and would therefore be the grade that would hold its weight better over time than the others.
 

Jay

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Good questions G-Man II, and I've put these questions to Mobil 1 before and was told that all of M1's 30-weights have VII's, including 10w-30. I can't remember how long ago it was though. It might have been before the SuperSyn series. I have a stack of questions that are overdue for asking so I'll call tomorrow myself and ask. I'm wondering about Amsoil's series 2000 0w-30. Is it built with the same philosophy as Mobil 1's 0w-30 and 0w-40, that is, using mostly various mixtures of esters to achieve it's 180 VI, or do they use predominantly polymer VIIs to do this?
 

G-MAN

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As an addendum, take a look at Red Line's straight weight racing oils. The 30wt has such a high VI (136) that it qualifies as a 10w30.
 

G-MAN

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Originally posted by Jay: Good questions G-Man II, and I've put these questions to Mobil 1 before and was told that all of M1's 30-weights have VII's, including 10w-30. I can't remember how long ago it was though. It might have been before the SuperSyn series. I have a stack of questions that are overdue for asking so I'll call tomorrow myself and ask. I'm wondering about Amsoil's series 2000 0w-30. Is it built with the same philosophy as Mobil 1's 0w-30 and 0w-40, that is, using mostly various mixtures of esters to achieve it's 180 VI, or do they use predominantly polymer VIIs to do this?
The SAE paper which documents Mobil's various tests of synthetics states that the viscosity spread of the 0w30 and 0w40 is obtained "primarily" from the blend of PAO and esters in the base oil blend. This means they DO use some VI improver, but it's not the "primary" factor in the spread.
 
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This is the first paragraph from the "Redline Synthetic Motor Oils, Technical Information," which was provided to me last month, by mail. There is no specific date on this information. RED LINE SYNTHETIC MOTOR OILS are designed to provide the highest degree of protection and cleanliness for your engine. We use the most stable synthetic components available and formulate our products for wear protection across a wide range of operating conditions. Red Line lubricants contain polyol ester basestocks, the only lubricants which can withstand the tremendous heat of modern jet engines, which makes our motor oil a necessity to properly lubricate a turbocharger or hot-running engine. The synthetic basestocks have a natural multigrade property, which means that large amounts of unstable polymeric thickeners are not required are not required to manufacture our multigrades. Red Line Synthetic Motor Oils will provide better protection than a petroleum oil of the next higher viscosity grade under high shear conditions. (italics added by me)
 

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Originally posted by Bill J.: This is the first paragraph from the "Redline Synthetic Motor Oils, Technical Information," which was provided to me last month, by mail. There is no specific date on this information. RED LINE SYNTHETIC MOTOR OILS are designed to provide the highest degree of protection and cleanliness for your engine. We use the most stable synthetic components available and formulate our products for wear protection across a wide range of operating conditions. Red Line lubricants contain polyol ester basestocks, the only lubricants which can withstand the tremendous heat of modern jet engines, which makes our motor oil a necessity to properly lubricate a turbocharger or hot-running engine. The synthetic basestocks have a natural multigrade property, which means that large amounts of unstable polymeric thickeners are not required are not required to manufacture our multigrades. Red Line Synthetic Motor Oils will provide better protection than a petroleum oil of the next higher viscosity grade under high shear conditions. (italics added by me)
Here is a quote from the Red Line tech info page. Since Red Line Synthetic Oils satisfy the high-temperature and low-temperature flow requirements of a multigrade without the use of unstable thickeners, all viscosity grades are suitable for high temperature and turbo use. (Italics added by me.) I suppose one could read this to mean that Red Line doesn't use "unstable" thickeners, but "stable" ones. I take it to mean, however, that they don't use ANY thickeners, and the relatiely low VIs of their oils would seem to bear that out.
 

mdv

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I'm definitely over my head technically here, but I've noticed a few things with the analysis results. Take Amsoil on one hand, an oil with a very high VI, so the inference seems to be that it will be less stable in grade. On the other hand, take Mobil 1, a lower VI oil, that would seem to be more stable based on this thread. Yet in real life, Amsoil tends to thicken with use while Mobil 1 tends to thin. Since the VI improvers are used to make the oil "act" thicker, wouldn't these oils tend to shear down instead of up? Am I missing something? Sorry to do the Amsoil vs. M1 thing again, but I thought it was the best example sice so much data exists for them.
 

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Originally posted by mdv: I'm definitely over my head technically here, but I've noticed a few things with the analysis results. Take Amsoil on one hand, an oil with a very high VI, so the inference seems to be that it will be less stable in grade. On the other hand, take Mobil 1, a lower VI oil, that would seem to be more stable based on this thread. Yet in real life, Amsoil tends to thicken with use while Mobil 1 tends to thin. Since the VI improvers are used to make the oil "act" thicker, wouldn't these oils tend to shear down instead of up? Am I missing something? Sorry to do the Amsoil vs. M1 thing again, but I thought it was the best example sice so much data exists for them.
The Amsoil results that show thickening seemed to be extended drain results over 10,000 miles. Keep in mind that an oil put through this could have sheared back at an earlier stage and then oxidized to thicken up at the later stage (i.e., just before the oil was finally changed). ALL oils will shear some, even those that don't have VI improvers. Hence, even if Mobil 1 has less VI improvers than other oils (or maybe none in some grades), it's still going to shear some under certain conditions. And since Mobil 1 tends to test out at the lower end of the viscosity range for a given grade, this shearing may seem more pronounced, even though it's not all that drastic.
 

mdv

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Originally posted by G-Man II: Keep in mind that an oil put through this could have sheared back at an earlier stage and then oxidized to thicken up at the later stage (i.e., just before the oil was finally changed).
I forgot about oxidation [Duh!]
 
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G-Man, are you saying that the Viscosity Index (VI) is directly related to the amount of Viscosity Improvers in the oil? I thought a high VI is a good thing? Isn't the higher the number, the more resistant the oil is to viscosity change with temp. or the other way around? Should we be looking at a LOW VI number in an oil? Or does this number mean little as an oil with a larger viscosity spread will naturally have a higher number than one with a lower viscosity spread and so it's nothing new?
 

G-MAN

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Originally posted by Dr. T: G-Man, are you saying that the Viscosity Index (VI) is directly related to the amount of Viscosity Improvers in the oil? I thought a high VI is a good thing? Isn't the higher the number, the more resistant the oil is to viscosity change with temp. or the other way around? Should we be looking at a LOW VI number in an oil? Or does this number mean little as an oil with a larger viscosity spread will naturally have a higher number than one with a lower viscosity spread and so it's nothing new?
One would think that an oil with a higher spread would have a higher VI, but looking at the numbers of the various oils I referenced that obviously isn't the case. Yes, the higher the number the more resistent an oil is to change in viscosity with temp. BUT the point of my original post was to point out that it SEEMS the oils that have the higher numbers MAY be the ones with the most VI improver, with the oils that have little or no VI improver having lower VI numbers.
 

Patman

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Originally posted by novadude: Are modern day VI improvers really that bad? [Confused]
They aren't as bad as before, but still not that good. Only the very expensive oils use VI improvers which are not too harmful.
 

G-MAN

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Originally posted by Patman:
quote:
Originally posted by novadude: Are modern day VI improvers really that bad? [Confused]
They aren't as bad as before, but still not that good. Only the very expensive oils use VI improvers which are not too harmful.

Which oils are those? It would seem that the really expensive oils (like Red Line) are the ones that don't use any VI improver.
 
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