BOQI II: The effect of HTHSV

[Shannow]

Now for the disclaimer
The above posts have neither
* been personal attacks
* denigrated the OP's qualifications
* nor claimed that any patent holder of Chevron Corp is unqualified

I am calling into question the assertions of the OP, in grabbing a whole bunch of numbers together, jamming them together, using specious logic and lack of science in presenting them as facts, and belittling anyone who dares question his "logic".

Could the above please be included in the mailing list that you guys have running ?

 

[Shannow]

Originally Posted by ZeeOSix

Do you have actual test data from a 24 hr Noack test to validate your calculations out to 24 hrs? That's what I was getting at.

Knowing you as long as I have now...I know how successful you have been at finding that validation...and I know precisely how much data the OP has to support his calculations.

 

[Gokhan]

Originally Posted by ZeeOSix
Do you have actual test data from a 24 hr Noack test to validate your calculations out to 24 hrs? That's what I was getting at.

Yes, here is the actual test data:

Determination of the NOACK evaporation loss of lubricants by TGA

 

[Gokhan]

Originally Posted by Shannow
Now what I find interesting about this thread, and the changes to the BOQI that apparently I prompted.

In the past, I have (quite rightly) criticised the BOQI for a couple of reasons.
* that using M1 Spectrasyn, it gave different "quality indices" for a range of oils blended with exactly the same family of basestocks.
* that using the 100% PURE basestocks, it gave different BOQIs - how could SS4, 6, and 8 all have different numbers if the index worked ???

Firstly Gokhan disclaimed that Mobil data sheet that he is now relying on as an indicative advertisement only, and not reflective of a real lubricant. Now that mashing the numbers together comes up with something...something meaningless, but still something...it's valid.

Secondly, the fact that the index didn't work for the first three members of the spectrasyn range has been ignored....that's important, as the origin of the BOQI was as a BLENDING TOOL...to estimate whether a blend would reach a target spec before breaking out the beakers.

So below is what the BOQI and the BOQI state about Spectrasyn 4, 6, and 8...note the wild variance in "quality" between 3 PAOs of the same process/family.

Your finished oil results are consistent with similar BOQI II values:

Your "neat" (pure) base-stock results would be consistent except for the 4 cSt base stock:

The constants in the BOQI calculations are empirical and chosen to ensure consistency between base stocks of different viscosities. The 4 cSt base stock would be more heavily used in a 0W-xx formulation and therefore it's more appropriate to use the CCS @ - 35 C for that. In general, I would use the CCS value where the base stock is still useable by itself. If you do that, you get BOQI II = 256 for the 4 cSt base stock and the results become consistent.

So, I don't see any problem here. Thanks for the data and calculations by the way!

 

[OilUzer]

Let's look at the big picture and I am trying to be very objective and nothing personal ...

One thing op should keep in mind is how this number (index) is going to help the average user (in this case bitog members) with their oil selection ... all ASSUMING that op has come up with a new, valid and useful piece of information (e.g. like good old Noack, hths, ccs, etc).

The old index (boqi) is utilizing 2 existing parameters: 1/(ccs*noack)
The new index (boqi ii) is including yet another existing (hths) parameter: boqi*hths

So the information (if any) is already there! Multiplying 2 existing parameters doesn't generate any additional info that wasn't there to begin with!!!

 

[Gokhan]

Originally Posted by OilUzer
So the information (if any) is already there! Multiplying 2 existing parameters doesn't generate any additional info that wasn't there to begin with!!!

You're missing the big picture.

CCS and HTHSV (oil thickness) are inversely correlated with Noack. Looking at them separately doesn't help you determine the base-oil type.

As an analog, to find the density of a material, you divide its mass by its volume. The resultant information is unique and can tell you what material it is. However, if you look at the mass and volume separately, you will be clueless.

 

[OilUzer]

I should've known by now that you have answers for everything! lol

Btw, I can divide in my head and don't need a calculator

 

[edhackett]

Originally Posted by Gokhan
Originally Posted by ZeeOSix
Do you have actual test data from a 24 hr Noack test to validate your calculations out to 24 hrs? That's what I was getting at.

Yes, here is the actual test data:

Determination of the NOACK evaporation loss of lubricants by TGA


Zee0Six, don't forget to multiply by the ad hoc correction factor of 41.14285714 so that 35 minutes equals 24 hours.

Ed

 

[Garak]

Originally Posted by JHZR2
Time in the NOACK test appears to me to be arbitrary.

This is what I've been saying all along.

When it comes to any index, in a more general term, the real problem we have here is a self-fulfilling prophecy, not to mention a great deal of mathematical uncertainty. Data sheets specifically have the disclaimer that they list typical values and do not constitute a specification. I don't see any uncertainty values, but we can make a rough enough guess with significant figures. Then, how do we test the result, as in verify the index?

 

[Garak]

Originally Posted by Shannow
Firstly Gokhan disclaimed that Mobil data sheet that he is now relying on as an indicative advertisement only, and not reflective of a real lubricant. Now that mashing the numbers together comes up with something...something meaningless, but still something...it's valid.

Unfortunately for the index, that same thing can be claimed for every data sheet out there. We have nothing that can be stated here to be predictive, since while there is a nugget of a testable hypothesis here, the number of people on the board who are in the position to actually test it with finished lubes can be counted on one hand and of those, those who actually want to do so seems to considerably lower. So, we're playing paper games, with paper specifications, and relying on MSDS numbers on occasion as some sort of verification here.

Aside from all the valid points made about where the index is failing in some of the examples brought up, we are stuck with something terribly untestable for the vast majority of us, and rather difficult to get a reasonable sample size even if we could. Me staring at pour point and flash point, and maybe glancing at Noack, and HTHS to think about the pour point, gives me enough hints about base stock. Of course, for the most part, CCS and HTHS can be guessed reasonably accurately by looking at SAE grade along with application (i.e. an ILSAC 5w-30 versus an A3/B4 5w-30).

 

[Solarent]

So I've read through both threads and I'm still not sure what it is that we are looking at here.
We are taking test results - that while influenced by base oil selection, are not connected in any way to base oil quality as a method for ranking base oil quality? That makes ZERO sense to me.

A simple review of the Base Oil Interchange Guidelines for finished lubricants as well as the work on using the Single Technology Matrix by additive companies to identify equivalent performance of finished oils in ACTUAL ENGINE TEST DATA identify the key factors that should be considered for ranking base oils in finished fluids:

1- BOV - this is the base oil viscosity which is the mixture of base oils selected to make the final blend. This is grade dependent and Viscosity Modifier Neutral. When comparing base oils, you have to compare the same BOV - because different mixtures have a wide impact on things like CCS and NOACK - which is I think why attempt to use these on a finished fluid is foolish.

2- Saturates content of the base oils used - there is no way you will get this information but is CRITICAL to ranking base oil quality. The impact of saturates is a critical attribute for using STM - which in effect ranks base oil quality by allowing equivalents to be defined.

3- Volatility is important - but this isn't measured with Noack which is a pretty arbitrary test. D2887 is used at 700 degrees as the main method as far as I am aware.

4- Sulfur content - sometimes this comes into play. It is less critical to BOI than the other factors.

You can't rate any of those 4 key factors using CCS vs Noack vs HTHS or any combination thereof.
Also note - the STM and BOI performance is well documented for Group II and II+ base oils, however for Group III rankings it is less well defined. I can assure you that CCS vs Noack has nothing to do with base oil quality.

I can confirm based on looking at many formulas and the impact of these factors on the finished characteristics of the oil that the difference between cuts of very similar base oils (ie Group III 4cSt combined with Group III 6 cSt vs Group III 4cSt combined with Group III 8 cSt that are are made using the same feedstocks and process at the same refinery) has a huge impact on both CCS and Noack but has zero impact on the quality and ability of that oil to perform it's necessary function.