Someone help me understand this...

[302Xplorer]

Why does, when it comes to Reg. M1, 10w-30 seem to be thinner than the 5w-30? I could be missing the point all together, so please help me out here Here are the respective data sheets: Mobil 1 10W-30 SAE Grade 10W-30 Viscosity, ASTM D 445 cSt @ 40º C 62 cSt @ 100º C 10.0 Viscosity Index, ASTM D 2270 147 Sulfated Ash, wt%, ASTM D 874 1.0 HTHS Viscosity, mPa·s @ 150ºC ASTM D 4683 3.14 Pour Point, ºC, ASTM D 97 -45 Flash Point, ºC, ASTM D 92 224 Density @15º C kg/l, ASTM D 4052 0.86 Mobil 1 5W-30 SAE Grade 5W-30 Viscosity, ASTM D 445 cSt @ 40º C 64.8 cSt @ 100º C 11.3 Viscosity Index, ASTM D 2270 169 Sulfated Ash, wt%, ASTM D 874 1.0 HTHS Viscosity, mPa·s @ 150ºC ASTM D 4683 3.09 Pour Point, ºC, ASTM D 97 -54 Flash Point, ºC, ASTM D 92 230 Density @15º C kg/l, ASTM D 4052 0.80

 

[GMorg]

M1 10W30 seems thinner because it is thinner. The exception is that 10W30 will solidify at a higher temperature. So at -45 C, 10W30 is thicker than 5W30. This is one of the reasons that I think that the "10W30 summer 5W30 winter" suggestion is sometimes flawed. HTHS is also different with 10W30 being higher.

 

[JAG]

Yep you read that correctly and the stupid viscosity grade classifications allow it. A good engineer or scientist could come up with a much more meaningful way to classify different oils. But tradition dies hard.

 

[427Z06]

Odds are the 10W-30 has less VIIs.

 

[GMorg]

Odds are neither has traditional VIIs.

 

[427Z06]

68% SHF-61/63, 15% SuperSyn2150, 7.65% Synesstic5, 9.35% Synesstic12 will get you very close to the 10w30. Can't see how you would get to the 5w30 without some VII unless they use some other trick us amateurs blenders aren't aware of. Even the HTHS numbers lend support to my conjecture.

 

[rpn453]

An SAE 30 oil can have a kinematic viscosity at 100 deg. C of 9.3 to 12.5 cSt. The "W" rating is separate from this rating.

 

[GMorg]

427Z06, I have no first hand knowledge about VII in the M1 line, but based on discussions here, it is my understanding that M1 5w30 has no VII. And, M1 is the oil which we are discussing. Below is a supporting quote from 'MolaKule' and a link to the thread in which the quote is found. It is one of several that can be found here. MolaKule wrote: "Mobil is the only company that can produce PAO basestocks up to 100 cSt and higher (at 100 C). So they have the ability to mix-and-match to arrive at any viscosity they need without VII's." Quote from (page 2): http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=001359;p=2#000026

 

[302Xplorer]

So am I cheating my car that calls for a 10w-30 by running the m1 10w-30? The 3800's are said to like an oil that is a little thick, should I just run the 5w-30. I wonder what the point is of enginering a 10w-30 to be thinner than your brand's 5w-30.

 

[GMorg]

I would bet that many oils are out there because the blender thinks that someone will buy them. I am still trying to figure out why Mobil has at least 4 different 5w-30s. But then again, I really think that it is marketing.

 

[427Z06]

quote:

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Originally posted by GMorg: I have no first hand knowledge about VII in the M1 line, but based on discussions here, it is my understanding that M1 5w30 has no VII. And, M1 is the oil which we are discussing. Below is a supporting quote from 'MolaKule' and a link to the thread in which the quote is found. It is one of several that can be found here.

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Yes, I remember that thread. However, I believe that EM now uses ANs in place of Ester basestocks in most of it's current formulations. I recall Terry or MolaKule griping about this more than once. Also, note that MolaKule didn't point out any specific grades, he just stated they had the ability to do so if they wanted to. Finally, I may be totally wrong on this but given the cost cutting corporate culture we live in, the performance and specs of the current products, at least my logic is somewhat sound. Maybe with a little luck we can get one of the resident chemist/tribologist to chime in.

 

[JAG]

GMorg, I think there is a misunderstanding. What Molekule was saying is that Mobil has very high viscosity basestocks available to them so they can make a motor oil with a high viscosity without using VI improvers, which of course increase viscosity (not just the viscosity index). He wasn't saying that they can make motor oils of very high viscosity index without VI improvers. Without them, the VI of the motor oil is some kind of weighted average of the VI of the basestocks and additive carrier. Most PAO generally has a VI>140. I am sure that Mobil COULD make a 5W-30 motor with a VI of 169 without VI improvers, but I don't think they did in the one above for the reasons 427Z06 gave, and because the density of the 5W-30 is lower (plastic-type VI improvers lower the density I presume), and because doing so would make it harder to pass the fuel economy requirements.

 

[427Z06]

Right-on, brother JAG.

 

[GMorg]

I still know that I do NOT know, but: Member 6905 wrote: "The current Mobil 1 5W-30 is reputed to include no VI improvers. Its high VI is a result of the blending of PAO with alkylated napthalene, as well as SuperSyn (HVI PAO). It's known to be very shear stable as a result, and stays in viscosity very well." from the following thread (page 1): http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=010839#000017 In addition, the suggestion is that the high viscosity PAO what makes this all possible.

 

[427Z06]

quote:

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Originally posted by GMorg: I still know that I do NOT know, but: Member 6905 wrote: "The current Mobil 1 5W-30 is reputed to include no VI improvers. Its high VI is a result of the blending of PAO with alkylated napthalene, as well as SuperSyn (HVI PAO). It's known to be very shear stable as a result, and stays in viscosity very well."

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That's exactly what I did above. I blended PAO, AN and SuperSyn (HVI PAO). Assuming no VII, the best I could do after much juggling of percentages and base oils was to match the 10w30 specs.

 

[rpn453]

quote:

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Originally posted by 302Xplorer: So am I cheating my car that calls for a 10w-30 by running the m1 10w-30? The 3800's are said to like an oil that is a little thick, should I just run the 5w-30.

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I believe your engine will do fine with either. I think they spec'd 10W-30 for that engine back when 5W-30s weren't as good as they are now. If you really want to go thicker, you could go with a 40.

 

[GMorg]

JAG/427Z06, I don't know where this fits in the discussion, but the density of M1 T/SUV 5w30 is the same as M1 10w30 and yet is has the same VI as regular M1 5w30 (and very similar viscosity profile). Is there a hint of what's different between regular and T/SUV M1?

 

[JAG]

Perhaps less VIIs, less AN (which has low VI), and more of the high VI basestocks? That's just a hasty guess. What the HTHS of the T/SUV? That may give a clue since VIIs raise VI considerably but don't raise the HTHS as much (% wise).

 

[GMorg]

JAG, It's the same, HTHS = 3.09. I am beginning to wonder if the density is a typo.

 

[JAG]

Hmmm, I dunno then. That's odd. Maybe 427 has an idea.