120 VI, a nice, neat divisible number to appease our fingers and toes. Given that arbitrary possibility, and putting on our tin foil hats, how close to that number do you think was determined scientifically vs. economically after the Mobil, Castrol ruling? Maybe that number was 10 points lower scientifically but concessions were made to protect Mobil’s investment? Who knows? What I do know is the process that ruled in Castrol’s favour by NAD is much the same for GRPII oils.

So that brings me to my next question, do you think oil manufacturers are chasing their tail a bit to meet the Synthetic price point and losing some flexibility in blending? Meeting the SN-GF5 spec, especially the Seq. IIIG, seems to dampen any major advantage GRPIII oils claim to have. That to me is what matters, not some marketing mumbo jumbo.

Your thoughts. Tangents welcome.

Disclaimer: I'm not an oil expert, more an oil embryo working on my featherweight status.

Viscosity index is simply a value based on the results of a logarithmic expression where the fluid's viscosity is measured at two temperature end points, and has nothing to do with the Castrol/Mobil fiasco.



There is no loss of flexibility in blending as I have a number of fluids I and others can use as "correction" fluids.

Except for the Beautique Oils, most synthetic OTS oils are primarily group III with added Group IV and V correction fluids.

Mathematics don't care but the marketing departments sure do. What's your opinion on GRPIII oils labelled as synthetic? Would you advise a > GRPIII for my vehicle?

Thanks.

We have all seen more than 2 or 4 UOA's on here do you detect anything that would suggest Grp III oils to be less protective or less durable than synthetics like Mobil 1?

Mobil I like most others is mainly Group III + oil blenders are showing less specs to hide what base oils are used. that law change IMO really STINKS!!!!

We have all seen more than 2 or 4 UOA's on here do you detect anything that would suggest Grp III oils to be less protective or less durable than synthetics like Mobil 1?

I'm not saying they're not, what I'm arguing is where that dividing line should be. There's benefits and disadvantages of GRP II's & III's. GRP II's have better solubility, EHD lubrication, PVC, traction co-efficient while higher groups have better thermal and oxidation resistance. I understand that motor oil is a complete formulation with different base oils and the additive package but if your adding something that you lost to make spec how much better is it for a particular application.

As many people know, my opinion is that Group III is a highly refined, highly processed mineral oil that does not meet the strict definition of what I consider a synthesized lubricant.

However, a Group III base oil has good performance wrt to resisting oxidation and thermal degradation, just slightly below PAO.

When correction oils are added to a majority Group III oil, such as PAO with AN or esters, there is no reason to worry about the solubility of additives.

In fact, so many additive chemistries are in ester form these days the problem of additive solubility is non sequitur.

I don't think any oil company or blender, who has good quality control, is short changing anyone.

I think the old logic on Grp III from yester year is completely different than the quality of today's Grp III's

If it wasn't you would see all sorts of engines dying prematurely and we aren't. Most people are oblivious to differences that exist.

We are just the "Tuners" of the world and demand the best. For me that's Grp-4 or higher.

Oil "Tuners".
Yeah, thats a pretty good description of BITOG

All base oils are essentially made 'to a price point'. I can't see what's wrong with that as the same logic applies to almost any other manufactured good you can think of.

You could in theory make a better Group I base oil by solvent extracting out more aromatics and removing more n-paraffins but this comes at the expense of making less finished base oil from a given amount of feed stock. A balance needs to be struck between quality and overall cost.

Exactly the same logic applies to Group II & Group III base oil production. The hydrocracking/catalytic dewaxing process by which you make these base oils is essentially the same. The only difference is the degree of process severity and that process severity comes at a significant cost because these technologies are destructive as well as reconstructive. The harder you hit the raw Vacuum Gas Oil feedstock, the more low value by-products you create (gas, naphtha, kerosene & diesel) and of course you produce less finished base oil. Groups II & III simply reflect two different balance points which have been struck.

It's interesting that once you eliminate relatively oxidatively unstable Group I from the engine oil equation (as is the case in the US), you end up with a range of base oils whose resistance to oxidation exceeds their needs in real life usage (US OCIs are still very low in comparison to the rest of the world). At this point you don't really need to fret much about sludge, varnish, viscosity increase, etc. You sort of reach a point where the only true differentiating points between finished oils, as you move up the base oil scale (from Group II to Group III to GTL to PAO), are Noack and a bit less VII.

I know a lot of noise is generated on the subject of 'proper' synthetic PAO versus 'Castrol cheating' Group III but to be honest, given that PAO costs three to four times as much as Group III, it's economically hard to justify its use given that the benefits are so marginal.

Beat me to it, M1, there's nothing wrong with it but it is Group 3+, skip the Roman numerals. At least most if not all of it is, in present formulation, which is what matters. Exactly right.



Observation: The very vast minority of the population. Not limited to, though We discuss things like how to get every single drop of oil from an engine, pan, filter, lines etc when minutiae such as this make not one iota of difference. Still, though, it's fun, and informative.

And what ruling was that? Please show what was decided and dictated AT LAW to constitute a ruling?

Sounds like you're trying to propagate wife's tales about group IIi without objective assessment.

You and benjy are both wrong.
Some M1 grades are known to contain majority Grp IV basestocks as evidenced by their published SDS documents.

Somewhere sometime here I'd read that pao in itself is not a good lubricant. That an entirely pao oil would be a bad thing? That pao's primary purpose is to lower the pour point. Is this fact or myth?

It was way before my time but I seem to recall the original Mobil 1 oil was all PAO and it was something of a disaster because PAO, on its own, causes seals to shrink and engines to develop leaks. This was fixed by always adding 10 to 15% Ester base oil (esters cause seals to swell and counteracts the shrinking caused by neat PAO). Other than that, I can't think why PAO would be a bad lubricant.

There was a time when if you wanted to make say a European 0WXX oil, then you were more or less committed to using PAO plus a splosh of Ester. This was because many of the first generation of Group III's (which were basically fuel hydrocracker bottoms) lacked the cold flow properties to make the CCS viscocity you needed for 0WXX oils. Since then, Group III processing (not forgetting GTL) has improved to the extent such that they've encroached into a lot of the 0WXX territory that used to be the exclusive preserve of PAO.