Synthetic Oils With Lowest VII's ?

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A few years ago, I asked some questions about VII here on BITOG, and was lucky to get some oil formulators answer me. I'll copy and paste below, for those interested.

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Question - SR5: Just say we have three 40 weight oils from the same name brand manufacturer.

The first is a top shelf, full synthetic, 0W-40, MB229.5, BMW LL-01 etc

The second is a middle level, semi-synthetic, 10W-40, A3/B4

The third is a economical to purchase, mineral, 15W-40, SN

What would be the differences in VII's used (type and dose rate)?

Answer - Solarent:

0W40 & 10W40 - odds are something like this would use a Styrenic Polymer but the treat rates would vary depending on the base oil choice. For example the 10W40 could have as low as 6-8% and the 0W40 as high as 18%. These VII's are generally more shear stable (5 SSI) but require more product to get the same level of thickening (polymeric efficiency). These polymers get chosen typically for shear stability, deposit control and dispersency are the main issues. Remember VII is only one part of the entire formula - so the formulator has to balance the VII needs with the rest of the DI package involved.

The 15W40 would most likely contain an OCP. probably something in the 25-35 SSI range. These polymers typically have good efficiency (meaning you get the required thickening at smaller concentrations) but they don't have the same level of shear stability and some would say that higher concentrations contribute to deposits in certain engine tests. OCP's are generally the cheaper of the two, so the final price of the product may reflect that.

There are lots of reasons why a formulator or oil marketer would choose to use different VII/VM packages - sometimes it's a performance requirement, sometimes its for reduced manufacturing complexity, sometimes its price. When you think about all the little details that go on to get to that final formula just right - you can probably see why formulators get annoyed when internet gurus and aftermarket companies thinks it's ok to mix in their own "special ingredients" as a way to improve on the formula - especially when there is no standardized testing involved.




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Joe90_guy:

Okay, from the top...

Olefin Co-Polymers (OCPs) are the most widely used of the VII polymers. They are made from ethylene & propylene which are the two simplest and cheapest olefins you can get hold of. The polymers can be made long or short. The long ones are more polymerically efficient at achieving a simple viscometric balance (KV100 & CCS) but tend to shear under mechanical & thermal stress. These are the so-called high Shear Stability Index (SSI) OCPs beloved by the US. The shorter, less efficient but more shear stable, low SSI OCPs are the norm in Europe.

The Shellvis VII polymers are made from stryene and butadiene. They can also contain extra hydrogen. Like OCPs, they can be made to various SSIs These olefins are more chemically complex and costly than simple ethylene and propylene. As a rough rule of thumb, Shellvis pure rubber is twice the price of pure OCP rubber.

At equal SSI, Shellvis is undeniably more polymerically efficient (ie you need less rubber) than OCP at achieving a simple KV100/CCS. However when you factor in cost, OCP is far more cost efficient. This largely explains why OCP is more widely used.

However life is never so simple. Today's engine oils can also be limited by Noack, HTHS, Bosch KO30 Shear and even viscometrically sensitive engine tests. Often an oil can be 'tight' on several limits simultaneously. However what limits are 'tight', and what limits 'float', will differ from viscosity grade to viscosity grade.

In certain circumstances, Shellvis can match or exceed the cost performance of OCP. This tends to happen more in the top-tier engine oils but often things can be confusing. There are still a lot of formulators that subscribe to the 'it's more expensive so it must be better for top-tier' philosophy.

One area where OCP's tend to trounce Shellvis VIIs is HTHS. At 100C & extreme shear (the conditions used in Bosch shear), the two VIIs are about the same. However when you ramp up to 150C (HTHS temperature), Shellvis starts to fall apart in a way that OCPs don't.

I would describe myself as very much in the OCP camp. I honestly don't like Shellvis. It's not just the high cost; it's the way they encourage 'bad outcomes' (eg low Group III 10W40's) and 'cheat' certain engine tests.
 
My understanding is that OCP is the VII of choice these days, as the star polymers and PMA have a hard time passing the turbocharger-deposit tests, as the former seems to be inherently dirty and the latter requires extremely high solid-polymer treat rates, which in turn increase the deposits.
 
Originally Posted by Gokhan


I wouldn't adjust the density-correction factor or make other changes in the calculation.

I know what is going on here. This particular table is from Infineum, not ExxonMobil. They probably used a different VII with a different polymer concentration in the solvent package. Again we need to remind ourselves that the VII contents reported in these ExxonMobil/Infineum tables are not the actual polymer treat rates but the whole VII package containing the solvent. It wouldn't surprise me if Infineum used a different type of VII in their HDEO guide than what ExxonMobil used in their PCMO guide. I estimate a 5.9% relative VII content for this oil, which actually makes sense because you would expect a fuel-efficient ILSAC GF-5 5W-30 to have more VII than a wear-reducing API CK-4 or ACEA C3 5W-30, the latter two of which have a higher HTHS. So, I think all is good here, and there are no surprises.


IIRC, I pulled both this, and the other table we were using earlier, from the same document, but I'll post it again here as you can see the colour scheme:
[Linked Image]


It's the red table that's from a different Mobil doc. It was matching up to the red table that primarily resulted in the tweaks to the density correction to make the numbers jive, but that same tweak appears to have helped with this product too, per my earlier post.
 
Originally Posted by SR5
A few years ago, I asked some questions about VII here on BITOG, and was lucky to get some oil formulators answer me. I'll copy and paste below, for those interested.

Answer - Solarent

Didn't Solarent do an entire thread about how the sky wouldn't fall with VM usage? Coulda' swore I came across a thread like that from several years ago...
 
Last edited:
Originally Posted by OVERKILL
IIRC, I pulled both this, and the other table we were using earlier, from the same document, but I'll post it again here as you can see the colour scheme:

It's the red table that's from a different Mobil doc. It was matching up to the red table that primarily resulted in the tweaks to the density correction to make the numbers jive, but that same tweak appears to have helped with this product too, per my earlier post.

Red table specifically mentions that they are using the star VII -- Infineum SV VM. My guess then is that they are also using the star VII (Infineum SV VM) in the HDEO formulation, but they are using the OCP VII, which is the preferred VII type, in all the other formulations. This would explain the discrepancy for the solvent-packaged VII content, as OCP VII and star VII are probably dissolved in different concentrations in the Group I base-oil solvent, as the solid molecular structures of the two polymers are entirely different.
 
Originally Posted by Gokhan
Originally Posted by OVERKILL
IIRC, I pulled both this, and the other table we were using earlier, from the same document, but I'll post it again here as you can see the colour scheme:

It's the red table that's from a different Mobil doc. It was matching up to the red table that primarily resulted in the tweaks to the density correction to make the numbers jive, but that same tweak appears to have helped with this product too, per my earlier post.

Red table specifically mentions that they are using the star VII -- Infineum SV VM. My guess then is that they are also using the star VII (Infineum SV VM) in the HDEO formulation, but they are using the OCP VII, which is the preferred VII type, in all the other formulations. This would explain the discrepancy for the solvent-packaged VII content, as OCP VII and star VII are probably dissolved in different concentrations in the Group I base-oil solvent, as the solid molecular structures of the two polymers are entirely different.


If this is the case, and requires a tweak to the density correction to properly account for, I think we need to figure a way to fit that in here somehow. Looks like CF of 0.930 works for the star VII, whilst .905 is more appropriate for OCP. The problem is knowing what's in the project you are trying to calculate VII content for.
 
Originally Posted by OVERKILL
If this is the case, and requires a tweak to the density correction to properly account for, I think we need to figure a way to fit that in here somehow. Looks like CF of 0.930 works for the star VII, whilst .905 is more appropriate for OCP. The problem is knowing what's in the project you are trying to calculate VII content for.

No, the density-correction factor shouldn't be changed unless you know that the actual density-correction factor is different.

Again, the VII content reported in the ExxonMobil/Infineum tables are not for the solid polymer. They are for the solid polymer + Group I base-oil solvent. If the concentration of the solid polymer in the Group I base-oil solvent is different for the star and OCP VIIs reported in those blending-guide tables, that doesn't tell us the actual relative treat rates for the two solid polymers. It's like someone diluting your beer with water (the analogue of solvent) -- you won't know how much alcohol (the analogue of VII) you're drinking by counting the glasses.
 
Originally Posted by Gokhan
Originally Posted by OVERKILL
If this is the case, and requires a tweak to the density correction to properly account for, I think we need to figure a way to fit that in here somehow. Looks like CF of 0.930 works for the star VII, whilst .905 is more appropriate for OCP. The problem is knowing what's in the project you are trying to calculate VII content for.

No, the density-correction factor shouldn't be changed unless you know that the actual density-correction factor is different.

Again, the VII content reported in the ExxonMobil/Infineum tables are not for the solid polymer. They are for the solid polymer + Group I base-oil solvent. If the concentration of the solid polymer in the Group I base-oil solvent is different for the star and OCP VIIs reported in those blending-guide tables, that doesn't tell us the actual relative treat rates for the two solid polymers. It's like someone diluting your beer with water -- you won't know how much alcohol you're drinking by counting the glasses.


I realize that, but we've already deviated from the original DF correction used in the A_Harman calculation. When I look at VII treat, I'd like it to align with real data. If we are using your .905 figure, we are still looking at a diluted (not just the solid polymer) treat % based on how well it correlates to the one blending table. Then, comparing it to the red table (also diluted, using a different VM we assume) we are way off. So neither are implicitly representative of the actual polymer content without its carrier, that's what I'm driving at.

I don't see modifying the CF as perverting the calculation, we are all aware that it's an educated guess and we have to assume things like VII type which we can't possibly know except for examples that show up in these blending guides. The red table is a good resource because of the extra significant figures for HTHS, which we must assume often involves some heavy rounding on many of the typical PDS's. Even with the other blending guide, HTHS has a more pronounced fudge factor.
 
First, the density-correction factor:

A_Harman's density-correction factor = 0.885 was definitely wrong, and we can disregard that entirely.

I believe I checked my density-correction factor = 0.905 against several oils with known temperature coefficients, and it seemed very reasonable.

The density-correction factor listed in the data sheets for various ExxonMobil SpectraSyn and SpectraSyn Plus PAO base stocks range between 0.911 and 0.914. They are a little bigger than my number, but we also need to take into account the DI package etc.
 
Second, I really need to clarify the meaning of the VII content in my calculation.

The primary goal of my spreadsheet is to calculate the dynamic base-oil viscosity at 150 C (BO DV150), not the VII content. The VII content is an intermediate number in the calculation.

After I calibrated the single adjustable constant in the calculation (VII viscosity-boost rate, set to be 10.5) against the data in the Hugh Spikes paper, the root-mean-square error for the dynamic base-oil viscosity at 150 C (BO DV150) for more than a dozen test oils was 6%, which was good.

However, the VII-content column neither refers to the solid polymer treat rate nor the amount of the VII package, which has the solid polymer dissolved in the Group I or Group II base-oil solvent. Note that A_Harman index measures the temporary-shear effect of the VII on the oil, in other words how much the high-shear viscosity (HTHS) is lower than the the low-shear viscosity. Since there are different VII types, such as SIPâ€hydrogenated styrene isoprene, OCPâ€olefin copolymer, PMAâ€polymethacrylate, and SBRâ€hydrogenated styrene butadiene, with subfamilies within each family, such as star SIP, linear diblock SIP, amorphous OCP, dispersant PMA, comb PMA, etc., it is impossible to relate the VII column, which is (1 - A_Harman index)/2, to the actual VII content without knowing the actual VII type, as each VII type has a different temporary-shear rate. However, the VII-content column, which was first invented by A_Harman and not by me, can be used as a measure of the temporary-shear effect of the VII on the oil.

Nevertheless, if two or more oils use the same or a very similar VII type, then the VII column in the spreadsheet can actually be used as a relative measure of the polymer treat rate or VII content.

When the full calculation is done and the dynamic base-oil viscosity at 150 C (BO DV150) is calculated, the VII type is blended in to the calculation, and the result for the base-oil viscosity is somewhat insensitive to the VII type, as the viscosity-boost and temporary-shear properties of VIIs are inversely proportional, and they tend to cancel each other out to some degree when you change the VII type; hence, the root-mean-square error for the base-oil viscosity is only 6% without even knowing the actual VII type.
 
*Excellent information Gokhan ! ... My stash of QSUD 5W30 , M1 5W30 and Castrol EDGE 5W30 will now be used for the older PFI engines in my signature - while my 2017 Sonata GDI engine (after CRC Intake Valve Cleaner) will use VAS 5W30 or PP 5W30 (which I need to buy moving forward). .
Originally Posted by Gokhan
Originally Posted by OVERKILL
Originally Posted by ChrisD46
Castrol EDGE 5W30 (USA) :
cSt K @ 100 degrees C. 10.7
VI 159

Castrol Magnatec 5W30 (USA) :
cSt K @ 100 degrees C. 10.4
VI 170

*So , with the exception of any "magic" added ingredients in the 5W30 Magnatec - the EDGE 5W30 would appear to have the lower VII's between the two formulations ?
Yup, that's likely a correct assumption. The Edge uses a higher VI base and less VII, whilst the Magnatec likely uses a lower VI, less viscous and less expensive base and more VII.

LOL. No!
laugh.gif


Look at the numbers. KV40 and KV100 are practically the same between the two.

It's typical Castrol. They made errors in their product data sheets. The actual VI is 159 and 162 for Castrol Magnatec 5W-30 and Castrol Edge US 5W-30, respectively; so, it's practically the same for both.

Castrol Magnatec 5W-30 and Castrol Edge US 5W-30 seem to be very similar oils if not identical.
 
*VAS 5W20 has a crazy low VII %0.23 !
Originally Posted by Gokhan
Originally Posted by painfx
Originally Posted by Gokhan
Here is the updated VII content (VII column) and base-oil viscosity at 150 C (BO DV150 column) table:

https://docs.google.com/spreadsheets/d/1oIYJP_5lgdt9l-_5n_ftKL5ScaaeY0MErFRothajZos/edit?usp=sharing
So looks like Valvoline has the least VII according to the spreadsheet.

Although on BITOG, majority of the people would say a high PAO based oil such as Mobil 1 EP/AP would be a better oil, and now Valvoline is Grp III/GTL based with lower VII, does this makes Valvoline better?

It's impossible to say. We can't say which oil is better based entirely on the HTHS viscosity, base-oil viscosity at 150 C (BO DV150), and VII content. The quality of the base-oil and additive package used, as well as the type and quality of the VII used, also matter, to say the least.
 
Since we are all talking about Valvoline Advanced Synthetic (North American blend), here is their spec sheet.

[Linked Image]
 
Originally Posted by Gokhan
However, the VII-content column neither refers to the solid polymer treat rate nor the amount of the VII package, which has the solid polymer dissolved in the Group I or Group II base-oil solvent. Note that A_Harman index measures the temporary-shear effect of the VII on the oil, in other words how much the high-shear viscosity (HTHS) is lower than the the low-shear viscosity. Since there are different VII types, such as SIPâ€hydrogenated styrene isoprene, OCPâ€olefin copolymer, PMAâ€polymethacrylate, and SBRâ€hydrogenated styrene butadiene, with subfamilies within each family, such as star SIP, linear diblock SIP, amorphous OCP, dispersant PMA, comb PMA, etc., it is impossible to relate the VII column, which is (1 - A_Harman index)/2, to the actual VII content without knowing the actual VII type, as each VII type has a different temporary-shear rate. However, the VII-content column, which was first invented by A_Harman and not by me, can be used as a measure of the temporary-shear effect of the VII on the oil.

Nevertheless, if two or more oils use the same or a very similar VII type, then the VII column in the spreadsheet can actually be used as a relative measure of the polymer treat rate or VII content..


OK, I think that's a good place to leave this then with respect to the figures being discussed in this thread.
cheers3.gif
 
Originally Posted by OVERKILL
OK, I think that's a good place to leave this then with respect to the figures being discussed in this thread.
cheers3.gif


Yeah, the VII content provided in the spreadsheet is merely a restatement of the A_Harman index. Rating the oils by the VII content in the spreadsheet is the same as rating them by the A_Harman index.

The relation for the A_Harman index is:

A_Harman index = (HTHS (high-shear))/(DV150 (low-shear))

The relation for the VII content is:

VII = (1 - A_Harman index)/s

Here s is the VII temporary-shear rate.

s strongly depends on the VII type. Since we don't know the VII type, we don't know s, and we don't know the actual VII content in terms of the polymer treat rate. Therefore, the VII content provided should be regarded as the "temporary-shear effect" of the VII, which both depends on the VII type and actual polymer treat rate. It's equally, if not more, useful as the polymer treat rate since the performance of the VII varies greatly with the type, and knowing the actual polymer treat rate does not necessarily help.

The relation for the base-oil dynamic viscosity at 150 C is:

BO DV150 (full-shear) = (DV150 (low-shear)) / (1 + (b/s)*(1 - A_Harman index))

Here b is the VII viscosity-boost rate.

b and s both strongly depend on the VII type. However, since b and s are somewhat proportional to each other when you change the VII type, it's possible to set b/s = c as a constant for all VII types and yet still get an accurate estimate (within about 6%) for the base-oil dynamic viscosity at 150 C without knowing the VII type.

The values b = 10.5, s = 2, and c = b/s = 5.25 have been chosen after calibrating the base-oil dynamic viscosity at 150 C to the data in the Hugh Spikes paper, which resulted in a 6% root-mean-square error. For the base-oil dynamic viscosity at 150 C, only the constant c matters.

Note that the base-oil dynamic viscosity at 150 C (BO DV150) includes the effects of both the base oil and detergent - inhibitor (DI) package. At extreme shear rates such as in the valvetrain, timing chain, and parts of the piston rings, the VII goes through full temporary shear through the full alignment of its molecules along the flow, and the only contributions to the viscosity come from the base oil and DI package, with none coming from the VII.
 
Originally Posted by painfx
Those are great numbers. If the SA is lower would be better.


But then you'd be giving up some wear protection and detergents.
 
Originally Posted by ChrisD46
Research may indicate that higher VII's in engine oils can lead to an increase in engine deposits (more critical in GDI and Turbo engines) .
The above said , which oils below have the lower VII's in their oil make up / formula ?

1. Valvoline Advanced Synthetic 5W30
2. Mobil 1 5W30
3. Pennzoil Platinum 5W30
4. Castrol EDGE 5W30
5 .QSUD 5W30

*I picked readily available synthetic oils all with D1 / Gen 2 , SN+ ratings .


VII is only one part of it, the additive's ash content and Noack may be the other. You just can't decide solely on VII.
 
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