List of oils by base-oil-quality index: 0W-20 oils

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Is this BOQI index model really no more than a tautology? Most of us are aware that lower than typical NOACK within a grade along with outstandingly low CCV within that same grade can reasonably be viewed as indications of a higher quality basestock blend, while those oils that brush the limits for both can reasonably be viewed as using a lower quality basestock blend. Is the BOQI model no more than a seemingly meaningful way of restating the obvious? Even if this is true, Gokhan has still done us a great service in finding and aggregating the numbers for a large group of oils in tabular format.
 

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Originally Posted By: fdcg27
Is this BOQI index model really no more than a tautology? Most of us are aware that lower than typical NOACK within a grade along with outstandingly low CCV within that same grade can reasonably be viewed as indications of a higher quality basestock blend, while those oils that brush the limits for both can reasonably be viewed as using a lower quality basestock blend. Is the BOQI model no more than a seemingly meaningful way of restating the obvious? Even if this is true, Gokhan has still done us a great service in finding and aggregating the numbers for a large group of oils in tabular format.
The idea originated from a Chevron/Oronite presentation that was linked in the original BOQI thread. You can read it there -- that thread is linked in the original post here. Basically NOACK is inversely proportional to the CCS within a given API group, and the proportionality constant is in turn proportional to the API group. So, if you multiply NOACK and CCS and then invert, you get the API group. Is this exact? Of course, no. There are various issues, such as VII in finished oil, other additives, and the fact that CCS is a function of temperature. However, it seems to be a useful comparison tool. Nevertheless, it shouldn't be taken as an absolute measure of base-oil quality. There are approximations in it, which may fail in certain cases. NOACK values also have up to about 7% test error, and therefore BOQI also has up to about 7% test error (not including the test error in CCS, which should be a lot smaller). Oil blends also constantly change. Regardless, it's a useful informative tool, and it beats advertising gimmicks.
 

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I've just read ASTM D5800-15a -- latest NOACK standard. From Section 13: The number of significant figures is one place after the decimal point. Therefore, the number of significant figures is two for NOACK less than or equal to 9.9 and three for NOACK greater than or equal to 10.0. From Section 14: The standard error for repeatability (within the same lab in a short period of time) = +/- 3% of the NOACK value The standard error for reproducibility (across different labs) = +/- 9% of the NOACK value So, if the NOACK value reported is 10.0%, it's 10.0% +/- 0.9%. PS: They report the 95% confidence interval in Section 14, which is twice the standard error. In the previous post, I mistakenly said that the reproducibility error was 7%, but it's about 9%.
 

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Coming back to the temperature issue, I rather use 1.75 and 1.73 for DV-35/DV-30 and DV-30/DV-25 as I did, rather than 2.00. Perhaps 2.00 is closer to finished oils and non-Newtonian oils but doing so would give thinner oils too much advantage in the BOQI calculation, and despite liking thin oils, I prefer to use a more conservative estimate (1.75) when comparing across 5W-xx and 0W-xx or 5W-xx and 10W-xx so that we don't end up punishing thicker oils unfairly because of the approximations involved.
 

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Originally Posted By: Gokhan
Coming back to the temperature issue, I rather use 1.75 and 1.73 for DV-35/DV-30 and DV-30/DV-25 as I did, rather than 2.00. Perhaps 2.00 is closer to finished oils and non-Newtonian oils but doing so would give thinner oils too much advantage in the BOQI calculation, and despite liking thin oils, I prefer to use a more conservative estimate (1.75) when comparing across 5W-xx and 0W-xx or 5W-xx and 10W-xx so that we don't end up punishing thicker oils unfairly because of the approximations involved.
The thinner oils generally have less VII in them, so I don't see the reason to "tweak" the calculation to level things out. You could use straight PAO and blend a 0w-20 with a less than spectacular VI but it would probably rank highly on the Index.
 
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When I used the term "tautology" what I meant was that your model merely repeats what we already know. Good NOACK combined with good W end performance indicates a high quality basestock blend. To achieve good numbers on either is easy but to achieve good numbers on both requires a nice slug of PAO or at least a high quality Grp III. Some of the RDS GTL basestocks, which are Grp III, appear to have extraordinary capabilities, but you don't really see this in current SOPUS products which are inferior in both NOACK and W end numbers to M1 in the same grades. I wonder how TGMO 0W-20 would score, if only Toyota would provide the numbers? As a Grp III oil that uses neither Visom nor GTL, probably mid-pack at best.
 

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Originally Posted By: fdcg27
I wonder how TGMO 0W-20 would score, if only Toyota would provide the numbers? As a Grp III oil that uses neither Visom nor GTL, probably mid-pack at best.
My effort in obtaining the TGMO 0W-20 SN technical datasheet resulted in an infinite loop with Toyota telling me to contact ExxonMobil and ExxonMobil telling me to contact Toyota. In fact the ExxonMobil guy I spoke with told me that "You should contact Toyota because they may not be happy about some specs we publish."
 

4WD

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He starts with that but read on ... his whole strange formula does nothing for me - it would say the Delvac 1300 in my 5.3L is useless when in reality I don't think an expensive 20 will protect it better ...
 
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Originally Posted By: 4WD
He starts with that but read on ... his whole strange formula does nothing for me - it would say the Delvac 1300 in my 5.3L is useless when in reality I don't think an expensive 20 will protect it better ...
Well, GM thinks it will protect better or at least as well since they call for it now in the {later models of the} 5.3L. And if want to use Delvac 1300, fine. But it's not less expensive than Mobil 1 AFE when purchased using rebates...
 

4WD

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For what ? 5 years/60k miles ? They worry about CAFE cause like for the last 20 years they make money off light trucks and the little cars "help" meet the new CAFE standards - but can't do it alone. Same with the 5.7 Mopar - will it survive if CAFE is not reined in some ? 20w in that 5.7L - no way without CAFE ...
 
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Originally Posted By: fdcg27
Most of us are aware that lower than typical NOACK within a grade along with outstandingly low CCV within that same grade can reasonably be viewed as indications of a higher quality basestock blend, while those oils that brush the limits for both can reasonably be viewed as using a lower quality basestock blend.
There's nothing wrong with wanting to make a rule of thumb more precise. But, if you want to do that, it had better hold up to mathematical scrutiny even before you get started. Gokahn: With respect to the 9% variability you acknowledged, now, you see how many ties you have in your rankings?
 
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It seems to confirm that for the most part, running any major brand of oil that meets your vehicles specs and needs will perform just fine. Look how many brands have done taxi tests or other types of testing. Marketing?, sure that's most of it. But there are real world results right here on BITOG of users running virtually every brand of oil and achieving many hundreds of thousands of miles on their vehicles with no problems. This "study" has confirmation bias written all over it.
 
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I don't humbug the idea of trying to find which oils have the better base stocks; one is trying to get "more" for one's money, even though that "more" really doesn't amount to anything in the end. Boutiques seem to make their living off that notion. In the end, though, you're right. Running an approved oil is generally going to be perfectly fine. If a model has general, somewhat widespread engine problems (i.e. sludging, premature wear), it's not the oil's fault. It's usually a manufacturing issue or inappropriate OEM intervals or specs. If it's specific, anecdotal problems, we see shoddy maintenance or just bad luck. "Use as directed" works just fine almost always.
 
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Oh I agree. A part of the issue here is the admitted bias by Gokhan that the 0w-20 oils are better than the rest and his using this formula to convince us. It smacks of a fan boy attitude in a way just like some say that Mobil 1 or Pennzoil is the best. That might sound harsh but it is the way I sense it. I have no brand loyalty in that respect but I do reach for brands that have served me well over the 45 years I have been driving and changing oil. Castrol, Havoline and Valvoline are my go to oils. If it weren't for the obvious bias and questions about the numbers etc., I would commend Gokhan on his efforts. There is nothing wrong with trying to find out which oil is better but that is a trait of BITOGers. Most people just put whatever they like or depend on someone else to put the right stuff in without any of this thinking.
 
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Yep. I have no problem using it for the most part when the manufacturer specifies it. However some cases make me wonder. An example would be the Honda 1.5 T-GDI. I would rest easier with a 5w-30. Then again, I should not be questioning the engineers who designed that engine though, its more likely that other factors such as CAFE played a big role in the choice of oil weight.
 

4WD

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Necessity is the mother of invention? Wonder what becomes (more of) a necessity at the 0w20 product line? Of course for the companies to make a profit - and the end user to find economic products to OEM/their specs - the formulation of all product lines can't all be expensive ingredients unless they ask $50/gallon like Redline does (even then, he's not impressed by Redline 10w30) ...
 
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