A_Harman index - base oils

[Gokhan]

Originally Posted by Shannow
LOL, just sitting here watching your posts change in real time...with not a single edit line or reason is priceless...

Still no answer to my question, which I repeated three times (and without an edit).

 

[4WD]

You realize Plus is the low vis product line ?

 

[Gokhan]

Originally Posted by 4WD
You realize Plus is the low vis product line ?

Yes, but so is the vanilla SpectraSyn...

https://www.exxonmobilchemical.com/...=20&pageNumber=2&selectedFacets=

 

[OVERKILL]

Originally Posted by Gokhan


(3) I proved that the HTHSV in the SpectraSyn datasheet is not correct. You can go through my proof. It's simple science and not an issue of trust or belief.


No, you've claimed it because you don't like the numbers. Let's try to keep this real, shall we?

 

[Gokhan]

Originally Posted by OVERKILL
No, you've claimed it because you don't like the numbers. Let's try to keep this real, shall we?

It's actually a proof. If the whole concept of the viscosity index has any meaning, a base oil with a higher KV100 and higher VI will have a higher KV150 than a base oil with a lower KV100 and lower VI. The higher-VI base oil is also a more premium version of the lower-VI one; so, we shouldn't expect anything fishy. We also ruled out temporary shear because these are both premium low-viscosity base oils.

Do you have any reason why this can't be the case?

 

[4WD]

That's 2015 and I should have said "was" ... Think it's SS and SSE now ...

 

[OVERKILL]

Originally Posted by Gokhan
Are you claiming that an improved-quality PAO base stock that is thicker at 100 C and has a higher viscosity index will have a lower viscosity at 150 C than an inferior PAO base stock that is thinner at 100 C and has a lower viscosity index?


Why is "regular" SpectraSyn "inferior"? It simply has a lower VI. It's main claim to fame is low volatility when combined with improved low temperature performance as per Mobil. This is obvious when you look at the rest of the data like KV -40, CCS, MRV:

SpectraSyn 6:
KV -40: 7,800cSt
KV 40: 31cSt
KV 100: 5.8cSt

CCS: 2,260cP
MRV: 7,310cP
HTHS : 2.08cP

SpectraSyn Plus 6:
KV -40: 7,400cSt
KV 40: 30.3cSt
KV 100: 5.9cSt

CCS: 2,247cP
MRV: 6,243cP
HTHS: 1.86cP


And this behaviour is the similar when you look at the 4cSt products:

SpectraSyn 4:
KV -40: 2,900cSt
KV 40: 19cSt
KV 100: 4.1cSt

CCS: 910cP
MRV: HTHS: 1.46cP

SpectraSyn Plus 4:
KV -40: 2,430cSt
KV 40: 17.2cSt
KV 100: 3.9cSt

CCS: 733cP
MRV: 2,023cP
HTHS: 1.24cP


For both ~4cSt @ 100C bases the HTHS of the higher VI "Plus" product is lower than the lower VI "regular" product, the same as with the 6cSt products. So, rather than assume that Mobil's data sheets are faulty, which seems ridiculous, I think the obvious answer here is that the higher VI PAO base oils in the "Plus" family respond different under the HTHS test than the "regular" PAO bases.

If you like, I'd be more than willing to reach out to Mobil and ask them.

 

[OVERKILL]

Originally Posted by Gokhan
Originally Posted by OVERKILL
No, you've claimed it because you don't like the numbers. Let's try to keep this real, shall we?

It's actually a proof. If the whole concept of the viscosity index has any meaning, a base oil with a higher KV100 and higher VI will have a higher KV150 than a base oil with a lower KV100 and lower VI. The higher-VI base oil is also a more premium version of the lower-VI one; so, we shouldn't expect anything fishy. We also ruled out temporary shear because these are both premium low-viscosity base oils.

Do you have any reason why this can't be the case?


It's not a proof. We don't have measured KV150 for starters, we have HTHS which imposes a shear characteristic to the measure. Molakule has stated that visc calcs aren't accurate, so we can't use KV40 and KV100 to accurately determine what KV150 is either. I think we are seeing more evidence that "all bases aren't the same" as per my original posit, and ties into why the A_Harman index for these bases seems "off".

I think the logical next step here is to reach out to XOM for more information.

 

[Gokhan]

Originally Posted by OVERKILL
Why is "regular" SpectraSyn "inferior"? It simply has a lower VI. It's main claim to fame is low volatility when combined with improved low temperature performance as per Mobil.

I didn't say "inferior" to the Plus. I said the Plus version is more premium. As far as I remember, the Plus uses a better catalyst that gives less branching.

Also, remember that my BOQI measures the base-oil quality by 1/(Noack x CCS); so, the Plus has a higher BOQI, as expected from less branching of the molecules.

 

[Shannow]

Originally Posted by Gokhan
I didn't say "inferior" to the Plus. I said the Plus version is more premium.


really ????

Now we are talking BOQI...do all of the SS plus oils give the same BOQI ?

 

[Gokhan]

Originally Posted by OVERKILL
Molakule has stated that visc calcs aren't accurate, so we can't use KV40 and KV100 to accurately determine what KV150 is either. I think we are seeing more evidence that "all bases aren't the same" as per my original posit, and ties into why the A_Harman index for these bases seems "off".

I think the logical next step here is to reach out to XOM for more information.

Go ahead and see if they have KV150. That would certainly resolve the issue. HTHSV is harder to measure because it's harder to keep the temperature at 150 C when the oil is under high shear. Again, there is no way the Plus, which is more premium, would be less shear-stable than the vanilla, and both should be very shear-stable (~ 99.9%) to begin with.

Regarding the ASTM D341 two-point viscosity extrapolation you and MolaKule are questioning, I don't buy that it would be off 10 - 20% as we are seeing here. 150 C is not that far off from 100 C. (In Kelvin absolute temperature units, 150 C is 13% higher than 100 C, which is in turn 19% higher than 40 C.) Again, it also makes no sense that it would work differently for different viscosities. I also don't expect grossly different behavior for the vanilla and Plus because their molecular structures are fairly similar except for the amount of branching.

 

[Shannow]

Originally Posted by Gokhan
Originally Posted by OVERKILL
Molakule has stated that visc calcs aren't accurate, so we can't use KV40 and KV100 to accurately determine what KV150 is either. I think we are seeing more evidence that "all bases aren't the same" as per my original posit, and ties into why the A_Harman index for these bases seems "off".

I think the logical next step here is to reach out to XOM for more information.

Go ahead and see if they have KV150. That would certainly resolve the issue. HTHSV is harder to measure because it's harder to keep the temperature at 150 C when the oil is under high shear.


But the off the shelf machines are offering 0.02C temperature control, and the ASTM tests are offering repeatability of less than 2.5%.

You keep referencing the notorious difficulty of measuring HTHS, and the temperature control "issues" as reason for Mobil publishing incompetent data...but the ASTM tests, and the off the shelf equipment simply don't demonstrate that as the causal link to their data sheets being falacious.

 

[Gokhan]

Originally Posted by Shannow
You keep referencing the notorious difficulty of measuring HTHS, and the temperature control "issues" as reason for Mobil publishing incompetent data...but the ASTM tests, and the off the shelf equipment simply don't demonstrate that as the causal link to their data sheets being falacious.

We don't know what machine, who, and what conditions were involved in the HTHSV measurement. Unless you have a scientific argument like mine based on ASTM D341 (my question you never answered), it's all speculation on your side.

 

[Shannow]

Originally Posted by Gokhan
Originally Posted by Shannow
You keep referencing the notorious difficulty of measuring HTHS, and the temperature control "issues" as reason for Mobil publishing incompetent data...but the ASTM tests, and the off the shelf equipment simply don't demonstrate that as the causal link to their data sheets being falacious.

We don't know what machine, who, and how was involved in the HTHSV measurement. Unless you have a scientific argument like mine based on ASTM D341 (my question you never answered), it's all speculation on your side.


I asked a bunch of questions regarding your various speculative concepts...none answered.

There's an ASTM standard for HTHS (well multiple)...it offers 2.3% repeatability and 3.6% reproducability...min to max about the mean measurement.
You claim that HTHS is notoriously difficult to obtain results...it's an ASTM standard, not some random lab with a goon spinning dials.
You claim that temperature control is the biggest single issue...the off the shelf test machines, that AUTOMATICALLY can process a dozen tests an hour are negating that claim, with 0.02C control at 150C.

So now "nobody knows the machine, who and how " validates YOUR speculation that Mobil are incompetent ???

 

[Gokhan]

Originally Posted by Shannow
I asked a bunch of questions regarding your various speculative concepts...none answered.

There's an ASTM standard for HTHS (well multiple)...it offers 2.3% repeatability and 3.6% reproducability...min to max about the mean measurement.
You claim that HTHS is notoriously difficult to obtain results...it's an ASTM standard, not some random lab with a goon spinning dials.
You claim that temperature control is the biggest single issue...the off the shelf test machines, that AUTOMATICALLY can process a dozen tests an hour are negating that claim, with 0.02C control at 150C.

So now "nobody knows the machine, who and how " validates YOUR speculation that Mobil are incompetent ???

I don't care what the expected repeatability etc. is. I am not arguing against this or you either. You still haven't learned that I don't like the silly bickering you constantly engage in. In fact, I hate it. That's why I appear not to answer you. You and I have different characters. That's not my style to be argumentative for silly ego. I don't have an ego issue like you do.

I made myself 100% clear. Based on my observation and the explained reason I have stated multiple times already, which you never responded, I suspect an error in the HTHSV value. Why do you still keep engaging me? You claim to want scientific discussion but you haven't said a single scientific thing in this thread. If you don't agree based on your repeatability or whatever argument, say so and leave it there, and don't waste my time and your time, as we both have better things to do. It's not that hard to agree to disagree. OK?

 

[Gokhan]

Originally Posted by OVERKILL
I think we are seeing more evidence that "all bases aren't the same" as per my original posit, and ties into why the A_Harman index for these bases seems "off".

I think the logical next step here is to reach out to XOM for more information.

Again, SpectraSyn and SpectraSyn Plus are practically the same base stock and it makes no sense for the concept of the viscosity index to appear upside down when you compare their reported HTHSV values. That's why I suggested that the reported HTHSV values are grossly inaccurate.

Yes, if you can get the KV150 (not the HTHSV) values for SpectraSyn 6 cSt and SpectraSyn Plus 6 cSt from Exxon Mobil, that would put an end to this mystery.

That's my two cents.

 

[ofelas]

Gokhan & Overkill - though you both seem to disagree on several points above, I find it refreshing that you both engage each other in a restrained manner, without resorting to personal attacks - makes it far easier for a base stock acolyte, for lack of a better term, to keep up my interest in this thread/discussion

 

[Shannow]

Originally Posted by Gokhan
We don't know what machine, who, and what conditions were involved in the HTHSV measurement. Unless you have a scientific argument like mine based on ASTM D341 (my question you never answered), it's all speculation on your side.


HTHS is a DIRECT measurement of an ACTUAL lubricant quality.

You are asking me to comment on your POV, by pointing at D341...an inferred value, which then requires a calculated density (which you've amply shown over the last few days contains it's own errors) to get to where you want it to be.

I've offered that the repeatability and reproducability of the actual DIRECT MEASUREMENT of the property in question is less than the problem that you are claiming.

yet you keep asking for commentary on a calculated value to divide by another calculated value to support your own calculated value twice removed...from any direct measurement.

While throwing up that we don't know the serial number of the machine used by Mobil reinforces your POV.

So in your lab...do you prefer for the purposes of grading students actual measured values, over extrapolations and inferences...and which then takes preference over common sense and gut feel ?

 

[Gokhan]

Originally Posted by Shannow
You are asking me to comment on your POV, by pointing at D341...an inferred value, which then requires a calculated density (which you've amply shown over the last few days contains it's own errors) to get to where you want it to be.

I've offered that the repeatability and reproducability of the actual DIRECT MEASUREMENT of the property in question is less than the problem that you are claiming.

yet you keep asking for commentary on a calculated value to divide by another calculated value to support your own calculated value twice removed...from any direct measurement.

While throwing up that we don't know the serial number of the machine used by Mobil reinforces your POV.

So in your lab...do you prefer for the purposes of grading students actual measured values, over extrapolations and inferences...and which then takes preference over common sense and gut feel ?

This is not a civil discussion. As I said before, let's agree to disagree. Please?

 

[Gokhan]

Originally Posted by Gokhan
Originally Posted by OVERKILL
I think we are seeing more evidence that "all bases aren't the same" as per my original posit, and ties into why the A_Harman index for these bases seems "off".

I think the logical next step here is to reach out to XOM for more information.

Again, SpectraSyn and SpectraSyn Plus are practically the same base stock and it makes no sense for the concept of the viscosity index to appear upside down when you compare their reported HTHSV values. That's why I suggested that the reported HTHSV values are grossly inaccurate.

Yes, if you can get the KV150 (not the HTHSV) values for SpectraSyn 6 cSt and SpectraSyn Plus 6 cSt from Exxon Mobil, that would put an end to this mystery.

That's my two cents.

Now, here is an interesting check I did.

Assuming that the SpectraSyn Plus 6 cSt is shear-stable and the reported HTHSV value is correct, using the operational-viscosity calculator backwards, you get KV40 = 42.50 cSt for the reported KV100 = 5.9 cSt, KV150 = 2.46 cSt, and HTHSV = 0.827*0.913*2.46 = 1.86 cP. This KV40 corresponds to a viscosity index of 72. Its actual reported viscosity index is 143, which is twice that.

It's hard to believe that the ASTM D341 operational-viscosity calculator would be that far off for such typical base stocks.