List of oils by base-oil-quality index: a ranking

[Gokhan]

Originally Posted By: BrocLuno
Since the DV-30 may not apply to 0W and 5W 40's, what index would you devise for them? They are of more interest to me than the 20's and 30's you list here.

It applies to 5W-40 and 5W-50 as well.

Shell Rotella T6 5W-40 is in the list. It got BOQI = 26.0, which is a very poor score for a full synthetic. No other full synthetic scored nearly that low.

Feel free to calculate BOQI for 0W-xx oils using the formula I provided but with DV-35 instead of DV-30. The only caveat is that you can't compare them to BOQI for 5W-xx oils calculated with DV-30. Likewise you can calculate BOQI for 10W-xx oils using DV-25 and so on.

 

[OVERKILL]

Originally Posted By: Gokhan
Originally Posted By: BrocLuno
Since the DV-30 may not apply to 0W and 5W 40's, what index would you devise for them? They are of more interest to me than the 20's and 30's you list here.

It applies to 5W-40 and 5W-50 as well.

Shell Rotella T6 5W-40 is in the list. It got BOQI = 26.0, which is a very poor score for a full synthetic. No other full synthetic scored nearly that low.

Feel free to calculate BOQI for 0W-xx oils using the formula I provided but with DV-35 instead of DV-30. The only caveat is that you can't compare them to BOQI for 5W-xx oils calculated with DV-30. Likewise you can calculate BOQI for 10W-xx oils using DV-25 and so on.


You could likely safely cut the CCS figure in half for a 0W-xx to get your 5w CCS.

 

[Gokhan]

Originally Posted By: 4WD
On the serious side - I was looking at my BMI numbers -
Man, it's been too hard to shed pounds/kg - so I'm going to try to grow taller ...

That's a good analogy to the BOQI!

 

[Puckrobber]

I'm always learning something new here on the BITOG! Granted, my high school & college educations didn't teach me anything about NOACK or VII's. But, it's nice to have a numbered list, and graphs, laid out in layman's terms, to learn about various oils.

Looking at this list has made me re-think my choice of 5w-30 oils for the H3. Might start looking deeper at the Quaker State and/or Pennzoil products. They seem to be very well made.

 

[chemman]

Thank you for the additional information! I learned some more about lubricants today!!!

 

[dnewton3]

It's a very interesting topic, and makes one ponder the implications.

But I don't see that it matters for most folks, most of the time. I don't care about the nuances of what goes in the bottle. I care about the results. What does wear data tell us? For normal applications, I don't see that high-end expensive lubes (that which would score highly in this BOQ list) do any better job of reducing wear or cleaning or cooling in a normal OCI in a healthy engine system, versus lower alternatives. If you go OUTSIDE normal those conditions (really long OCIs, previous neglect, cooling/fuel/air systems malfunctioning, etc), then maybe it matters.

I've run some really inexpensive oils in UOA testing, but they were always API certified. And they do every bit as well as expensive lubes, even when pushed further than most folks would believe. For example the W/M ST lubes scored low on your list, but I've run them in successive LONG OCIs (dino 5w-30 out to 15k miles in a soccer-mom mini-van application) and yet the UOA wear data was not just "OK", but excellent. Even when pulling the valve cover, there was no undue sludge or varnish. So, the low BOQI score you give belies the performance it really provides. Also, you advise to avoid those which score lower than 22.0, but Motorcraft semi-syn 5-30 comes in a 21.9 ... This is a lube that traditionally turns in very good UOA data.

I agree that lubes which are highly rated on this BOQ list may have more POTENTIAL to perform better IF really extreme conditions would warrant. But most of the time, they are products that possess excess capacity that will NEVER be utilized. Even "normal" products have more capacity than most folks use. Having more of an unused capability is just waste. It's a measure of "better" than never materializes into usefulness.

The lubes at the top of the list have a BOQI approximately 3x higher than those near the bottom. If I were to use a lube with BOQI at 75, versus a lube with BOQI at 25, am I going to be able to see a tangible difference of 3x less wear, or 3x cleaner head surfaces, or 3x better fuel economy, or 3x easier starting in cold weather ... I think you see where I'm going with this. The scale has no real value. The BOQI scale provides an ability to rate lubes on a list, but that scale has no value in terms of real world function. PU does not provide 3x less wear than ST dino oil in a 10k mile OCI. PYB is 3x better than Chevron Supreme, Motorcraft or Valvoline White bottle oil? I'm sorry, but macro statistics wear-data just does not support such a claim.

I don't see any correlation between your list and real world product performance in the crankcase.

 

[Virtus_Probi]

If one is willing to trust their self-reported numbers, Amsoil 5W30 SS also does quite well...roughly 71.1 based upon my read of a chart of their results on 2012 oil in 2013 tests.

Maybe not a lot more useful than the result for Pennzoil Ultra that was discontinued not long after that testing, given that Amsoil says they are going to reformulate their line to perform better in LSPI testing. But, it should be easier to stock up on SS now than try to find Ultra that has been sitting around for a few years.

 

[Gokhan]

Originally Posted By: Virtus_Probi
If one is willing to trust their self-reported numbers, Amsoil 5W30 SS also does quite well...roughly 71.1 based upon my read of a chart of their results on 2012 oil in 2013 tests.

Maybe not a lot more useful than the result for Pennzoil Ultra that was discontinued not long after that testing, given that Amsoil says they are going to reformulate their line to perform better in LSPI testing. But, it should be easier to stock up on SS now than try to find Ultra that has been sitting around for a few years.

From the current Amsoil technical datasheet on its Web site, I get the following BOQI values:

BOQI Oil

79.2 Amsoil Signature Series 5W-20
67.4 Amsoil Signature Series 5W-30
53.5 Amsoil Signature Series 5W-50

I would take Amsoil's NOACK values with a grain of salt though.

It's interesting that (based on Amsoil's own numbers) Amsoil Signature Series 5W-30 exactly ties the all-time champion discontinued Pennzoil Ultra 5W-30.

 

[Gokhan]

Correction:

It's interesting that (based on Amsoil's own numbers) Amsoil Signature Series 5W-30 5W-20 exactly ties the all-time champion discontinued Pennzoil Ultra 5W-30.

 

[Gokhan]

Originally Posted By: Gokhan
Originally Posted By: chemman
I am going to defer to Molakule for a more detailed explanation, but I do not see how inverse cP divided by % NOACK (the units of the equation) can be an indicator of base oil quality.

This is a very good question! I didn't put the answer to it in the original post because I wanted to keep it brief.

My base-oil quality index (BOQI) was inspired by the following presentation:

Global perspective on lubricant specifications and how it affects base-oil quality (link)
John Rosenbaum, Chevron Global Base Oils

If you look at the two key figures of the presentation, the curves for the NOACK vs. CCS viscosity of a given base oil are approximately in the form:

(NOACK) x (CCS viscosity) = constant

In other words, they are inversely related to each other for a given base oil.

Moreover, the "constant" here is inversely proportional to the base-oil quality given by the API Group numbers (I, II, III, IV, GTL, etc.). Smaller the constant is, higher the API Group or higher the quality of the base oil is. Therefore, the inverse of the constant directly gives the base-oil quality. Therefore, I define the base-oil-quality index (BOQI) as follows:

BOQI = 2,000,000/(NOACK x CCS viscosity)

Here 2,000,000 cP was chosen to make the BOQI approximately between 10 and 100.

As I mentioned in the original post, it's crucial to compare the BOQI using the CCS viscosity at the same temperature for all oils, 5W-xx oils being reported at -30 °C for example. This makes it hard to compare a 5W-xx oil to, say, a 0W-30 oil because chances are very high that you won't find the CCS viscosity for them reported at the same temperature.

One caveat that I didn't mention in my original post: Viscosity-index improvers (VIIs) in the finished oil may somewhat alter the CCS-viscosity numbers for a base oil but for comparison purposes this doesn't seem to be an issue.

Note that NOACK is not really dimensionless but has the units of inverse time, as it represents the evaporation rate (as in percent mass loss per unit time). However, when it's expressed, the time period in which it's measured (1 hr = 3,600 s) is omitted (or set to "1") for simplicity. So, the BOQI has actually the units of not inverse dynamic viscosity but inverse pressure. It's therefore an intrinsic physical property of the base oil. Perhaps this pressure can be thought of as a tiny pressure, which is about 1 - 2 nanoatmosphere for a typical base oil, caused by the defects in the base oil, and the smaller the pressure is, less the number of defects in the base oil is and higher the quality of the base oil is.

 

[Shannow]

So how come this index gives different outcomes for the basestocks in the two charts that were used to define it ?

edit...different temps..:doh: for me

 

[pbm]

When we talk about "the discontinued Pennzoil Ultra 5w30", I assume we're talking about the original version before the reformulation? Does anybody know on what date (of manufacture) that change happened since PU 5w30 is still available? I have several qts. of older (although still SN rated) PU and didn't realize just how 'special' it is.

PS: I agree with dnewton3 that most of us will never utilize the potential of these oils, if in fact it exists. In other words, I doubt that 2 identical vehicles, one run on PU or QSUD with 10K OCIs....the other run on VSP for 10K OCIs would show much difference in engine wear after 100K or even 200K.

 

[BobFout]

On the topic of Rotella T6 5w-40, it's the only 5w-40 HDEO tested. You are comparing grapefruit and grapes. Do you have the same calculations for Delo, Delvac and other HDEO 5w-40? Where are the 15w-40 HDEOs for comparison?

Are there any other 5w-40, Euro-types, to include?

No one should expect sub-par performance from RT6 5w-40, as it meets stringent industry and manufacturer standards ... different standards compared to PCMOs.

Rotella and Delo are similarly priced. Should we expect poor performance from Delo too?

 

[Wick]

The baseline sample measurements for AMSOIL ALM 5W-20 Signature Series engine oil are as follows –

3612 ppm Calcuim
162 ppm – Molybdenum
229 ppm – Boron
14 ppm – Magnesium
708 ppm – Phosphorus
770 ppm – Zinc

8.6 cSt – Viscosity
11.9 mg KOH/g – Base Number
48 abs/cm – Oxidation
5 abs/0.1 mm – Nitration

found out their sulfated ash levels are 1.5 % by weight , thats real high compared to others

I received those number right from Mr Bender who is the master blender at Amsoil

 

[jorton]

#4 is from a recent test(2016) so one can conclude current sopus still excell.

 

[Pablo]

Originally Posted By: Gokhan

67.4 Amsoil Signature Series 5W-30


I would take Amsoil's NOACK values with a grain of salt though.



Why?

7.5 v. 7.6

http://www.amsoil.com/lit/databulletins/g2880.pdf

http://www.pqiamerica.com/ATF Feb 2012/2012 April results/Amsoil.htm

and 3954 v. 3398

OR 67 v. 77

 

[Wick]

Pablo, one thing about Amsoil, they will change their formulas and never tell you, according to their latest blog they are going to reformulate for lower Saps numbers, I have be a long time user and preferred customer, for that money I can do much better

 

[BobFout]

Originally Posted By: Wick
Pablo, one thing about Amsoil, they will change their formulas and never tell you, according to their latest blog they are going to reformulate for lower Saps numbers, I have be a long time user and preferred customer, for that money I can do much better


Does any lubricant manufacturer communicate this [formulation changes] to the end consumer?

 

[fdcg27]

Dave, you make your usual and always compelling point that it really doesn't matter in any way that can be measured.
However, if Gohkan's thinking is correct and his simple formula really does indicate base oil quality, which I'm not entirely convinced of, then why not purchase the better quality product than one of lower quality offered for the same or more coin?
Can't do any harm, might do some good and I, like most people, try to get the best value I can for any amount spent.

 

[BrocLuno]

Well, one of the drivers of this is NOACK. That is partial evaporation of the base oil as percentage over time. So quality is determined by less evaporation. And that may be a laudable goal in hot running engines. But in engines with oil coolers and large sumps, the loss from NOACK never even comes close to the losses from seepage and blow-by, in my experience.

Or, saying this another way, as the light fractions boil off, the oil should get thicker. That is a good thing if you are trying to counter shear effects

I think that is, in part, what makes HDEO's so successful in 20,000 mile OCI's in big rigs. Things stay balanced and the engine runs well and long