Can Straight-grade motor oils contain VII's?

[Drivebelt]

I've noticed that a fair amount of people are under the impression that straight grade motor oils (or single grade as they are referred to in many product sheets) contain no VII's (viscosity-index-improvers). In another thread, I pointed out that I saw no reason why a straight-grade motor oil cannot have VII's in it.

A straight grade SAE 30, 40, 50 only has to fall within the viscosity range for that particular grade. For a 30 weight that would be 9.3 - 12.5 cSt at 100C. There are 2 ways to get there. One can blend a oil in that range with no VII's, or, one can use a lighter viscosity oil (like a 7.0 cSt) and use some VII's to get it within the range. Straight-grade simply means that the oil meets the viscosity for that grade and the company is not claiming any multi-grade properties -- it doesn’t necessarily mean that the oil has no VII's.

I gave an example of a single-grade Petro-Canada product, HD 30.pdf, which has a VI of 123. This product is either a Group II or a Group II/I blend. Since the VI of the base oils used in this product are ~ 100 (or marginally over that) I suggested that P-C's HD 30 is using some VII's.

It may be typically that straight-grades don't use VII's, but I don't see that as a technical requirement.

Agree, disagree?

 

[G-MAN]

You are absolutely correct. There is nothing that prevents them from blending a "straight" grade with some VI improvers. The key indicator is the VI of the finished oil. Absent some other explanation, I would say once you start seeing a VI of >115 on a straight 30, then there is a strong likelihood that the inherent VI of the dominant base oil used is getting a boost from somewhere. The issue then becomes, from where?

In the case of the Duron, they could be tossing in a little bit of VHVI Group III to lower the pour point.

In the case of the Valvoline 30 with its VI of 113, I think this is made from Group I+ and the esters used in the additive pack are kicking the VI up a bit.

 

[Drivebelt]

Ok, good.

I was thinking that maybe "single-grade" had become a marketing term like synthetic. And it was expected that these oils have no VII's.

Those Group I based straight grades with VI's around 107 had me wondering too. On Esso's (Canadian) site, the single grade HD 40 and 50 have a VI of 93 -- right where the VI of their Group I solvent refined base oils fall.

But when I checked many other SAE 30, 40 grades, they have quite a bit higher VI's. I'm still curious, as to how those Group I based single grades are getting the VI up to ~ 106 when the GI base oils are a good 10 points lower or more.

 

[G-MAN]

Maybe Bruce (our resident blender) will chime in hear with a few pearls of wisdom.

 

[wileyE]

Pour point depressants and possibly some other additives could extend the VI without vii's?

 

[wileyE]

also basestocks of different groups and visc could be blended to make the straight weight?

 

[G-MAN]

Yes and yes.

I think advanced additive technology used to meet the SM specs are why we see the higher VI on SM rated straight grades. You'll note that the straight grades with the lower VIs still carry API SL and SJ ratings.

 

[XS650]

The 1993 version of SAE J300...

"oils which are formulated with polymeric viscosity index improvers for the purpose of making them multi-viscosity grade products are non-Newtonian products and must be labeled with the appropriate multi viscosity grade....

After eading all of J300 It looks clear that if the oils don't contain polymeric VI improvers, they don't need to be labeled multi-grade, no matter what the VI.

There is also verbiage in J300 that says a multi-vis oil must be labeled with the lowest W grade it meets.
For instance, if an oil meets 5w30, you can't call it a 10w30.

 

[wileyE]

Probably wouldn't even be straight grade "labeled" oils on the shelf if there weren't still owners manuals that call for them? I mean if they were labeled for what they are we'd probably have a lot of 25w30, 30w40 and goofy grades to obsess over, LOL.

 

[G-MAN]

Quote:

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"oils which are formulated with polymeric viscosity index improvers for the purpose of making them multi-viscosity grade products are non-Newtonian products and must be labeled with the appropriate multi viscosity grade....

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That quote right there shows why the HT/HS vis of a straight grade is the product of the HT, while for the multi-grade it's the product of both HT and HS.

 

[Merkava_4]

I don't think I'd want a straight grade oil with viscosity index improvers in it; that kind of defeats the whole purpose of buying a straight grade oil in the first place, which is having an oil that gets all its viscosity from the base oil.

 

[XS650]

Quote:

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Probably wouldn't even be straight grade "labeled" oils on the shelf if there weren't still owners manuals that call for them? I mean if they were labeled for what they are we'd probably have a lot of 25w30, 30w40 and goofy grades to obsess over, LOL.

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Do you remember the old 20W-20 grade.

My edition of J300 also commented that most straight grade oils met some multi-vis combo. 20W-20 shouldn't be too hard with modern base stocks.

 

[G-MAN]

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Probably wouldn't even be straight grade "labeled" oils on the shelf if there weren't still owners manuals that call for them? I mean if they were labeled for what they are we'd probably have a lot of 25w30, 30w40 and goofy grades to obsess over, LOL.

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Do you remember the old 20W-20 grade.

My edition of J300 also commented that most straight grade oils met some multi-vis combo. 20W-20 shouldn't be too hard with modern base stocks.

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Any 20W could be labeled as a 20w20, though not every SAE 20 could be labeled as a 20w20.

I'd be willing to bet that if the SM rated Valvoline 20W (VI of 125) and 30 (VI of 113) were tested for cold cranking and cold pumping the 20W would meet the specs for a 10w20 and the 30 would meet the specs for a 20w30.

 

[XS650]

You would have to find someone else to bet against.

 

[Craig in Canada]

Quote:

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You are absolutely correct. There is nothing that prevents them from blending a "straight" grade with some VI improvers. The key indicator is the VI of the finished oil. Absent some other explanation, I would say once you start seeing a VI of >115 on a straight 30, then there is a strong likelihood that the inherent VI of the dominant base oil used is getting a boost from somewhere. The issue then becomes, from where?

In the case of the Duron, they could be tossing in a little bit of VHVI Group III to lower the pour point.

In the case of the Valvoline 30 with its VI of 113, I think this is made from Group I+ and the esters used in the additive pack are kicking the VI up a bit.

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I see where you're going, but I'm not sure you can generalize like that. A VII-free single-weight oil could be blended from any group of base stock and still contain no VIIs. The VI would be all over the place, even possibly exceeding 115, but still no VIIs would be present.

I would be interested in approximate VI figures for VII-free base stocks of each grade.

I think this thread may have originated from some Amsoil ASE threads in the other boards. ASE is AFAIK a group IV, I'd love to know whether its VI of 146 means that VIIs are used despite lots of words implying that they don't without coming right out and guaranteeing it. Of course, even if VIIs are used, some are better than others. GC seems very shear stable, while M1 0W40 doesn't have that same reputation.

Craig.

 

[bruce381]

Sraight wts can have VII in them
Kinda a waste but is OK

Additives such as dispersants and PPD will riase the VI without a VII

 

[Max_Wander]

passionate blenders are like fine chefs, there are no rules, do what tastes good... err performs the best

 

[TallPaul]

Can PAO and/or ester be considered a VII when added to a lower group base oil?

That kind of VII I would have no complaints about.

 

[bruce381]

""Can PAO and/or ester be considered a VII when added to a lower group base oil?"'

No I would call them adjusters for PP or soulbility only
VI kick IMHO is to small.
bruce

 

[Dad2leia]

Bruce381, what level can the VI go to without suspecting VII being added other than the PP adjusters and dispersant items?