We don't know who's using what in their blends, beyond one or two major components gleaned from Safety Data Sheets
Originally Posted By: OVERKILL
But that's based on the assumption that they are just going to use less VII in the narrower spread.
In most cases of ILSAC 5W vs 10W I've seen it appears to be the case. When comparing published data like density, NOACK and VI, it strongly suggests that many normal 10Ws are indeed straighter, heavier-base blends with less VII dependence than the 5Ws. It's too bad Mobil doesn't share NOACK results, not to suggest they'd be poor quite the contrary. I'd just like to see how each Mobil grade stacks up to each other for insight to how they're built, though admittedly, I'm not very interested in how XOM does things.
Originally Posted By: OVERKILL
M1 5w-30 has 20-30% PAO in it according to the MSDS
M1 10w-30 has 10-20% PAO in it according to the MSDS
One could posit that they simply used more PAO for the 5w-30 to get the low temp performance and both oils may have the same or very similar VII treatments.
Sure thing, so we agree that they achieve VI by increasing PAO use while while not exceeding a limit of VII. Surely blenders must have a limit on the amount of artificial viscosity they'll use in any blend, you know, for stability (and liability) reasons.
Originally Posted By: OVERKILL
Then what about EP or AFE? It isn't like AP is the only product line in which they use PAO, and the AP product portfolio doesn't have any significant ACEA or Euro certifications, so I'm failing to see your point here?
PAO is everywhere. It's an important and staple building block, No argument. Just more of it =/= more robust wear protection and therefore =/= an absolutely better finished product.
About the AP, it's clearly a long drain oil and as such (apparently) shares a blending strategy in common with Euro ACEA and LL oils given it's higher PAO content. Oxidation and viscosity retention are obv. top priorities there. That's why I called it a copycat Euro LL oil, because by all accounts it is- like EP but with a gimmick attached. The dumb thing is that it's targeted to North American consumers who's vehicles don't require OEM spec'ed long-drains and who are unaware of existing manufacturer-certified LL oils. But the "once a year" thing is really simple to understand, easy to remember and apparently more convenient. Personally, if I wanted LL I'll go ACEA or manufacturer spec.
Originally Posted By: OVERKILL
if you shop for a product that is highly certified, you end up with one that is forced to be blended to a higher quality standard, like the 0w-30 we've already talked about.
True that. The said specs yeild much higher quality oil in many very desirable categories indeed, but is PAO's film strength and HDL performance one of them? How would more PAO and/or GrIII contribute to the quality of hydrodynamic lubrication vs more Gr I, II and/or V
Originally Posted By: OVERKILL
An ILSAC 10w-30 is nowhere near that, ergo, they contain a good dose of VII and a lighter base blend,
Lighter base blend than a SAE30, no doubt but most likely a heavier base blend than the 5w30 and less VII. When you consider the data points mentioned above (density, NOACK, VI, KV) on various lines, The 5w20 and 10w30 appear to be the straightest vs the 0Ws and the 5w30. Check Petro-Canada's TDS for eg. with their hydroisomeric based blends, and the data strongly suggests heavier but straighter blends on the narrow spread products.
Originally Posted By: OVERKILL
But given my Mobil examples above, that seems like a rather bold assumption on your part, no? The fact that you are looking at ILSAC 10w-30's means you are almost assuredly looking at products with VII's in them, as a 10w-30 that's blended with straight base oil will tend to have an HTHS much higher than the ILSAC grades, or have you not considered that?
We don't know if we can correlate HTHSV to VII polymer usage. I personally have not seen much data regarding the natural HTHSV of the various base oils and blend ratios, so can't say much to what the HTHSV 150 for the various possible blends of VII-free 10W30 would exactly be. The bulk of HTHSV testing undoubtedly happens on finished products.
I can say one thing for sure: Shame on any chemist and blender who's 10W30 contains more VI polymer than it's identical 5W30 counterpart. (and so I doubt many could be offended by that statement
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Originally Posted By: OVERKILL
I think you are reaching a bit here. AMSOIL's HD 10w-30/SAE 30 for example, has an HTHS of 3.6cP with a KV100 of 11.3cSt.
Hey, I could just forget everything and go grab some Redline Ester-based Motorcycle oil for the most extreme protection and call it a day.
But that's neither practical or economical.
btw I love the characteristics of esters if my handle is any indication. PAO-ester blends are fantastic and synergistic but too much PAO, with only 'additive-levels' of ester content are not so hot IMO.
Originally Posted By: OVERKILL
PAO is used because of its natural ability (no wax) to hit CCS and MRV targets for low temp performance as well as, as you've indicated, oxidative stability.
No doubt and no argument. It's clean, molecularly-tailored, uniform, stable and wax free but it's absolutely not the best lubricating fluid.
Originally Posted By: OVERKILL
You still have to blend it with something else, and that can be a POE, AN or Group III, or a blend of those things, in order to hit your performance target. Nobody has said that a PAO-blend is necessarily polymer-free (though the AMSOIL example above is), simply that you need less of it with a PAO blend because you can be closer to your target visc out the gate as the low temp performance is already far better than with other bases.
Absolutely. Saturated, non-polar bases are good, clean stable 'filler' (IMO), but the real superstar components are the additives used to make dry base oil useful. The solubility improvers, GrV fluids used as SIs and FMs, plus dispersants are the only thing keeping additives and contaminants in solution, the PAO/GrIII isn't doing a darn thing here besides taking up space (which too is an important job!). Quality hydrodynamic lubrication suffers from PAO/GrIII content, and also from VII content. Those two ingredients are absolutely critical for meeting specific viscosmetrics, but are poor hydrodynamic lubricants relative to other base types and compensating additives.
Originally Posted By: OVERKILL
I assume you mean Mobil's MSDS's, as they are the only ones that have been helpful in this regard. What about Redline? AMSOIL? You think they are using a ton of Group III or something else? This is quite the rabbit hole.
The Castrol SDS for the 0w30 A3 showed ~50% PAO. Even your Mobil example at ~65% for their highest spec'ed blends leaves a lot of room and I doubt it's all expensive ester additives, instead probably GrIII, AN and ester etc, but that's just my consumer-grade speculation. (Our whole discussion is consumer-grade
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Originally Posted By: OVERKILL
You thinking like Group II stuff here? Mixing SpectraSyn 10 at 93% and 4 at 7% yields a 9.35 (just on the edge of the 30 weight range) that should be able to satisfy the 5w-xx designation grin but that of course uses your maligned PAO base
Got no problem with GrII. I'd happily run straight GrII blended oils in car engines @ appropriate service intervals, heavy industry has sure relied on them for decades with excellent HDL and wear protection. Also, it's not 'maligning'. PAO is a building block; a tool and I'm just highlighting the fact that it's not a panacea and not without weaknesses. More of it doesn't mean better lubrication.
Fair?
