Mobil AP, strange HTHS?

[Shannow]

Originally Posted By: Gokhan

You are still not getting the key puzzle here that no mainstream oil, let alone a full synthetic, has KV100 almost 12 cSt with HTHSV only 3.0 cSt, ACEA A3/B4 or not.


Back in the day, M1 0W40 in Oz had "Energy Conserving" on the package. This was when the 40s had the 2.9HTHS minimum.

When they got the MB and BMW 35,000km certification, M1 0W40 was renowned for thinning in service (oft down into 30KV territory), then thickening up if left in long enough.

I don't see this new oil as much different in intent to that early M1 0W40 behaviour.

 

[Gokhan]

Originally Posted By: Shannow
Originally Posted By: Gokhan

You are still not getting the key puzzle here that no mainstream oil, let alone a full synthetic, has KV100 almost 12 cSt with HTHSV only 3.0 cSt, ACEA A3/B4 or not.

Back in the day, M1 0W40 in Oz had "Energy Conserving" on the package. This was when the 40s had the 2.9HTHS minimum.

When they got the MB and BMW 35,000km certification, M1 0W40 was renowned for thinning in service (oft down into 30KV territory), then thickening up if left in long enough.

I don't see this new oil as much different in intent to that early M1 0W40 behaviour.

You are referring to older HTHSV limits imposed more than 20 years ago. 2.9 cP was only a lower limit, not the actual HTHSV value. All or most 10W-40s were labeled Energy Conserving in the 1990s and it had nothing to do with those HTHSV limits. In contrast 5W-30 and 10W-30 oils were labeled Energy Conserving II. API later removed the Energy Conserving altogether from 10W-40 oils. Are you claiming that Energy Conserving 10W-40s back then had HTHSV less than 3.5 cP? I doubt they had HTHSV values any different than 10W-40s today.

You can't also seriously claim that the top-of-the-line Mobil 1 AP SN/RC has been made to the standards of the 1990s Mobil 1 0W-40 SH/EC and it will first shear in service and then thicken later.

 

[Shannow]

Originally Posted By: Gokhan

You are referring to older HTHSV limits imposed more than 20 years ago. 2.9 cP was only a lower limit, not the actual HTHSV value. All or most 10W-40s were labeled Energy Conserving in the 1990s and it had nothing to do with those HTHSV limits. In contrast 5W-30 and 10W-30 oils were labeled Energy Conserving II. API later removed the Energy Conserving altogether from 10W-40 oils. Are you claiming that Energy Conserving 10W-40s back then had HTHSV less than 3.5 cP? I doubt they had HTHSV values any different than 10W-40s today.

You can't also seriously claim that the top-of-the-line Mobil 1 AP SN/RC has been made to the standards of the 1990s Mobil 1 0W-40 SH/EC and it will first shear in service and then thicken later.


The HTHS limits for the xW40s were 2.9 for a reason (and they wree only upped relatively recently).

Early BITOG, the behaviour of the 0W40 was well known...And where did I make that claim regarding the modern one doing the same ?

You can quote me if you like..

I was stating that the new oil appears to have been designed similarly to that to prevent too much thickening in service (supported by buster's graph)

 

[Gokhan]

The reason I dwelled into this was because I thought the OP's question was less trivial than ACEA-A3/B4 xW-30 oils vs. non-ACEA-A3/B4 xW-30 oils, for which many people here are familiar with the minimum-HTHSV specs of 3.5 cP and 2.9 cP, respectively.

I went ahead and analyzed the viscosimetric properties for Mobil 1 oils and calculated the A_Harman index, which is an indication of how much VII is present and how much they temporarily shear during the high-shear environment of the HTHSV measurement.

The results were somewhat inconclusive because not only M1 AP 5W-30 resulted in a low A_Harman index but also M1 HM 5W-30 did. These two oils are outliers that seem to have a higher percentage or a more shearing type of VII in them. Of course, the numbers reported in datasheets have measurement errors in them and there may even be typos. In any case I am not impressed with the viscosimetric properties of M1 HM 5W-30 and M1 AP 5W-30, assuming the reported numbers are accurate.

And that M1 AP 5W-20 seems to have almost no VII at all for those who don't like VIIs.

Enjoy the numbers!

Code:
Oil Density KV40 KV100 KV150 HTHSV VI DV150 A_Harman index



M1 0W-20 0.841 44.80 8.70 3.91 2.70 177 2.91 0.928

M1 5W-20 0.852 49.80 8.90 3.89 2.75 160 2.93 0.938

M1 5W-30 0.855 61.70 11.00 4.75 3.10 172 3.59 0.862

M1 EP 0W-20 0.839 44.90 8.60 3.85 2.70 173 2.86 0.944

M1 EP 5W-20 0.850 49.60 8.90 3.90 2.75 161 2.93 0.937

M1 EP 5W-30 0.851 59.80 10.60 4.57 3.00 169 3.44 0.872

M1 HM 5W-20 0.856 50.00 8.60 3.72 2.70 150 2.82 0.958

M1 HM 5W-30 0.856 72.00 12.10 5.09 3.10 166 3.86 0.804

M1 AP 0W-20 0.840 45.69 8.70 3.89 2.60 172 2.89 0.899

M1 AP 5W-20 0.850 48.88 8.20 3.53 2.60 141 2.66 0.979

M1 AP 5W-30 0.851 63.33 11.70 5.09 3.00 183 3.83 0.783


I am not going to try to guess the base stocks used in M1. However, MSDSs show varying amounts of PAO, from 5% to 60%, depending on the viscosity and variety. We also know that M1 has been using mainly Visom Group III+ base stocks lately in combination with some PAO and a small amount of ester, and they call the Visom Group III+ base stocks "GTL precursor," meaning it may transition to GTL at some point. Here is the only official information we have on this matter, in case you haven't seen it:

Mobil 1 PAO - Group III+ - GTL transition (PDF link)

 

[Shannow]

Cool, will look into it more later...found this during my lunch break and will tabulate later.Google Books Link High Shear Viscometry Oils

Note the early days they used CST, thus the high numbers.

Use a representative density for 150C (0.75 ish), and see what was on the market...

 

[Gokhan]

 

[1JZ_E46]

Does the A_harmon index actually mean anything? Rooted in science? I am skeptical. Just seems like a random calculation of publicly available numbers but with no real meaning.

 

[Shannow]

Originally Posted By: 1JZ_E46
Does the A_harmon index actually mean anything? Rooted in science? I am skeptical. Just seems like a random calculation of publicly available numbers but with no real meaning.


Yes, it's recieved a bagging on a certain little blog, which has caught on.

Newtonian fluids (without VII) do not change viscosity as the shear rate increases, as there's no VII to flatten out...Multigrades with VII DO change viscosity with shear rate, they get thinner.

So the Harman Index
* uses the KV40 and KV100 to calculate a KV150...in Cst (Kinematic viscosity).
* then multiplies that by density to get the 150 viscosity in Cp (just like the HTHS is measured in).
* then compares the ratio of the HTHS to the Newtonian measure, as a percentage.

So it's rooted in science...

In "seems like a random calculation"...I'm happy to hear how you've come to a different conclusion.

 

[CharlieBauer]

Originally Posted By: Shannow
So the Harman Index
* uses the KV40 and KV100 to calculate a KV150...in Cst (Kinematic viscosity).
* then multiplies that by density to get the 150 viscosity in Cp (just like the HTHS is measured in).
* then compares the ratio of the HTHS to the Newtonian measure, as a percentage.


Has Gokhan performed step 2 correctly in his table?

Originally Posted By: Gokhan
Code:
Oil Density KV40 KV100 KV150 HTHSV VI DV150 A_Harman index



M1 0W-20 0.841 44.80 8.70 3.91 2.70 177 2.91 0.928

M1 5W-20 0.852 49.80 8.90 3.89 2.75 160 2.93 0.938

M1 5W-30 0.855 61.70 11.00 4.75 3.10 172 3.59 0.862

M1 EP 0W-20 0.839 44.90 8.60 3.85 2.70 173 2.86 0.944

M1 EP 5W-20 0.850 49.60 8.90 3.90 2.75 161 2.93 0.937

M1 EP 5W-30 0.851 59.80 10.60 4.57 3.00 169 3.44 0.872

M1 HM 5W-20 0.856 50.00 8.60 3.72 2.70 150 2.82 0.958

M1 HM 5W-30 0.856 72.00 12.10 5.09 3.10 166 3.86 0.804

M1 AP 0W-20 0.840 45.69 8.70 3.89 2.60 172 2.89 0.899

M1 AP 5W-20 0.850 48.88 8.20 3.53 2.60 141 2.66 0.979

M1 AP 5W-30 0.851 63.33 11.70 5.09 3.00 183 3.83 0.783

 

[Gokhan]

Originally Posted By: CharlieBauer
Has Gokhan performed step 2 correctly in his table?

Yes, the density reported is at 15.6 C. I multiplied it by 0.885 to get an estimate at 150 C. (This was prescribed by A_Harman.) I didn't show this in the table but it's there.

 

[CharlieBauer]

Originally Posted By: Gokhan
Originally Posted By: CharlieBauer
Has Gokhan performed step 2 correctly in his table?

Yes, the density reported is at 15.6 C. I multiplied it by 0.885 to get an estimate at 150 C. (This was prescribed by A_Harman.) I didn't show this in the table but it's there.


Thanks.

So the best oil is M1 AP 5w20 and the worst oil is M1 AP 5w30. In fact it's 25% better.

That makes total sense.

Somebody needs to alert Mobil.

 

[Gokhan]

As Shannow described, yes, A_Harman index is very scientific.

A_Harman index = HTHSV/HTLSV (high-temperature, high-shear viscosity divided by high-temperature, low-shear viscosity)

For a monograde oil, A_Harman index = 1 exactly.

For a multigrade oil, it tells you exactly how much the VII temporarily shears in high-shear environment. (Note that this is not to be confused with permanent shear.)

Therefore, it's an indirect indication of the percentage of VII present in the oil and/or the temporary-shear rate of the VII.

Since HTLSV is not reported, first KV150 is estimated using KV40 and KV100. This is then multiplied with the density at 150 C to get DV150 = HTLSV. (KV means kinematic viscosity and DV means dynamic viscosity.) However, first, the density at 150 C also has to be estimated by multiplying the density at 15.6 C by 0.885.

 

[Shannow]

Originally Posted By: Gokhan

Yes, the density reported is at 15.6 C. I multiplied it by 0.885 to get an estimate at 150 C. (This was prescribed by A_Harman.) I didn't show this in the table but it's there.


I use this
https://planetcalc.com/2834/

same diff...

 

[Shannow]

Originally Posted By: Gokhan
As Shannow described, yes, A_Harman index is very scientific.

A_Harman index = HTHSV/HTLSV (high-temperature, high-shear viscosity divided by high-temperature, low-shear viscosity)

For a monograde oil, A_Harman index = 1 exactly.


Yes, and a pictorial representation for the naysayers...again, to demonstrate the science...

This is a typical chart used to describe the "shear stability index"...the vertical lines are the permanent losses at low shear and high shear respectively (note high shear is about 40(ish) percent of the low shear, as the VII molecules are less effective in high shear, and thus their loss is less apparent).

The sloping line (purple) is the representation of change in viscosity with changing shear rate. If it was a monograde, that line would be horizontal (that's flat for the cadre on the blog).

The Harman Index is the ratio of the high shear viscosity to the low shear viscosity...using the only information that we have available...manufacturer's data sheets.

The "random calculation" caper is the conversion of Cst to Cp, something that the people also find difficulty with, as Cp and Cst are only the same number (that was a problem with 101, Haas didn't know the difference) on water, density 1,000 KG/m^3.

 

[1JZ_E46]

Thanks everyone for the A_Harmon index explanation.

 

[1JZ_E46]

Originally Posted By: 1JZ_E46
Thanks everyone for the A_Harmon index explanation.


But does the index really matter from an application standpoint? I understand what it shows, but I don't think it has much in the way of real-world significance. Plus, which I think is the bigger issue, there is a lot of estimation that goes into the calculation, it makes the assumption that all of the data points are calculated the same across multiple manufacturers, and the precision of inputs is all over the map. Remembering back to my physics class days, I don't think you can have 4 significant figures at the end. Maybe two at most. Proper rounding also needs to be done to intermediate calculations. At no point should your calculated value have more sig-figs than the input value. And since HTHS is usually one decimal point, the other side of the fraction, HTLS, needs to also use on decimal point.

 

[CharlieBauer]

Originally Posted By: 1JZ_E46
Plus, which I think is the bigger issue, there is a lot of estimation that goes into the calculation, it makes the assumption that all of the data points are calculated the same across multiple manufacturers


Which kind of rebuts the idea that the numbers being calculated on this website are "scientific".

 

[Shannow]

Originally Posted By: CharlieBauer
Originally Posted By: 1JZ_E46
Plus, which I think is the bigger issue, there is a lot of estimation that goes into the calculation, it makes the assumption that all of the data points are calculated the same across multiple manufacturers


Which kind of rebuts the idea that the numbers being calculated on this website are "scientific".


LOL, so
* it's a meaningless random jumble of numbers...until it's demonstrated that it's not.

* now it's "you are assuming that everyone tests the same"...so it's meanigless.

And clearly shows a lack of understanding of J300...

The little numbers next to the description of the measure are the ASTM tests which apply for those viscosities.

So unless the oil cos are using the STANDARDISED tests for certification, then got to 540RAT to write their data sheets, then it's a fair guess.

Correct on the significant figures, but don't confuse places after the decimal with them.

And yes, if you are comparing the impact on VIIs on the finished product, then looking at the Harman Index for CITGO SAE30 (1), Ravenol 0W16 (0.99) and TGMO (0.85) tells you an awful lot about the temporary shear thinning of an oil...and by inference the possibility of permanent.

Comparing M1 0W30 versus 5W30 not so much.

 

[Gokhan]

Originally Posted By: 1JZ_E46
Remembering back to my physics class days, I don't think you can have 4 significant figures at the end. Maybe two at most. Proper rounding also needs to be done to intermediate calculations. At no point should your calculated value have more sig-figs than the input value. And since HTHS is usually one decimal point, the other side of the fraction, HTLS, needs to also use on decimal point.

Your knowledge on significant figures is rusty. First, you never round off the intermediate results until you reach the final answer. Second, in multiplication and division, the number of significant figures is not the number of decimal figures but the number of all figures.

Therefore, since the lowest significant figures in the calculation, coming from HTHSV, are two or two and a half significant figures, A_Harman index also has two or two and a half significant figures. But then who cares it's 84.1% or 84.4%? 84% is more than enough precision for a quantity like that.

As far as it's usefulness, it tells you about the VII in the oil. It's like many other parameters representing an oil. Physical effects of the VIIs are another discussion.

 

[CharlieBauer]

Has anybody collected the actual KV150 of oils and compared them to the theoretical KV150 that this index is calculated on?

Would not seem to be very scientific to suggest an index has some sort of validity if a theoretical number is the most important part of it's calculation and the validity of the calculation of that theoretical number has not been explored.