Group II/II+ vs Group III

[Coastal]

Just looking for some info on Group II and II+ oils vs Group II. I know that there is a VI difference on II and III with III having to be, I believe, 120 or great VI base stock; group II being less than 120 VI. Are the impurity levels, sulfur, ash, etc. the same between the two.

I know that in the Motor Oil 101 section it states that petroleum 10w30 is 10 weight oil with viscosity improvers that cause the oil to act as a 30w at operating temp and that synthetic is 30w with VI that allows it to be thinner at cold temps, but I didn't know if that held true for Group III or if it was specific to Group IV and V

 

[electrolover]

will be watching this thread

 

[demarpaint]

Me too.

 

[Nick R]

 

[Coastal]

Just a disclaimer.... Not trying to start a debate about which one is better. Just legitimately looking for the main differences between the two. I know that the VI of the base stock is a major part of it, but I am curious as to what the requirements (if any) are for impurities are between II and III. FWIW, I've used both and and still do. Just trying to get a little education.

 

[Coastal]

I also read a few documents that I could find on the subject and the only specs I saw stated:

Group II VI 80-120 Saturates >90% Sulfur Group III VI >120 Saturates >90% Sulfur
And that an oil could be considered Group II= if it was 113-120 VI.

Some of the other stuff that I read indicated that GRP III was likely to have lower volatility, but didn't specifically mention that it was required by spec.

 

[chubbs1]

VI is VI no matter what group an oil is in (to start with) how it gets to it's end VI is what is important and the main difference between quality Grp's. 1/II/II+/III/IV/V. VII's are very important I would advise that the most important thing you look for is a good reputation from the field, NOACK, Good VI 140 to 175 and a major brand. You are really answering your own questions and there should be little debate between the two groups (they are what they are it is what is added to increase VI that counts IMO). Look at what the oil is claiming to be semi-syn, syn etc and I look at the spec sheets and see if it has a ridiculous VI (like 200+ for a "blend")
Watch out for the viscosity index, cheap VI's will shear to garbage in no time. You should know the oils I am talking about.

 

[tinmanSC]

Interesting question. We have seen many post (some less interesting than others about I/II/III/VI/V, but I don't recall any data about the II/II+.
*adds thread to watched list*

 

[chevrofreak]

There is also such thing as a III+ which has a VI of 140 or greater. Shell's XHVI base oil falls into this category, and is what is used in Rotella T6.

 

[ltslimjim]

Originally Posted By: chubbs1
VI is VI no matter what group an oil is in (to start with) how it gets to it's end VI is what is important and the main difference between quality Grp's. 1/II/II+/III/IV/V. VII's are very important I would advise that the most important thing you look for is a good reputation from the field, NOACK, Good VI 140 to 175 and a major brand. You are really answering your own questions and there should be little debate between the two groups (they are what they are it is what is added to increase VI that counts IMO). Look at what the oil is claiming to be semi-syn, syn etc and I look at the spec sheets and see if it has a ridiculous VI (like 200+ for a "blend")
Watch out for the viscosity index, cheap VI's will shear to garbage in no time. You should know the oils I am talking about.


Good contribution. +1.

Originally Posted By: chevrofreak
There is also such thing as a III+ which has a VI of 140 or greater. Shell's XHVI base oil falls into this category, and is what is used in Rotella T6.


Partly why I'm using it in my current fill.

 

[Lead Shoes]

dumb question I'm sure, but what does the viscosity index have to do with the group of oil its in?

 

[chevrofreak]

Originally Posted By: Brenden
dumb question I'm sure, but what does the viscosity index have to do with the group of oil its in?


Groups I, II and III are all made from petroleum, so they need to be able to distinguish them. Groups II and III are made using similar processes, but III is more processed and results in a higher viscosity index. II+ is simply on the high end of the VI spectrum for II, and III+ is on the high end for III. Group III+ is usually made from hydroisomerized slack wax and is extremely pure and can be considered a "true" synthetic. Shell's XHVI base stock and Mobil's Visom are examples of this.

http://en.wikipedia.org/wiki/Lubricant#Base_oil_groups

 

[Tom NJ]

More discussion on group differences here:

True synthetic oil

Tom NJ

 

[Coastal]

Originally Posted By: chubbs1
VI is VI no matter what group an oil is in (to start with) how it gets to it's end VI is what is important and the main difference between quality Grp's. 1/II/II+/III/IV/V. VII's are very important I would advise that the most important thing you look for is a good reputation from the field, NOACK, Good VI 140 to 175 and a major brand. You are really answering your own questions and there should be little debate between the two groups (they are what they are it is what is added to increase VI that counts IMO). Look at what the oil is claiming to be semi-syn, syn etc and I look at the spec sheets and see if it has a ridiculous VI (like 200+ for a "blend")
Watch out for the viscosity index, cheap VI's will shear to garbage in no time. You should know the oils I am talking about.


With a good portion of the 5w30 conventionals out there, they are pretty high in VI and not much off the pace of the Group III synthetics in that final VI number. Pennzoil Conventional has a VI of 158 and Ultra has a VI of 169. I would assume that Ultra needs less Viscosity Improvers to reach that VI number, but I would also assume that Pennzoil uses quality Viscosity Improvers to reach their number on Pennzoil conventional, so I'm not really sure what to make of the difference. Kind of a similar situation with Mobil Super 5w30 and Super Synthetic 5w30 with 158/162.

I'm not really sure what brands are using cheap VI's. I would think that products from Havoline and Pennzoil would be using quality viscosity improvers, but don't really know for certain.

 

[Coastal]

Also, I don't recall the exact required content, if any, of synthetic oil that a blend must have to be designated a "synthetic blend." I thought that it might have to be 30%, but it could be lower. I would suspect that some of the conventional oils that we have on the shelf today could potentially have a small amount of GRP III or other to meet the required specs, even though it could be less that what is required to be called a synthetic blend, if their is a requirement. I recall reading a Chevron document that indicated that it would be difficult for most PCMO producers to meet the newer specs with dino without using what they consider unconventional base oils. This was before GF-5/SN, so I'm sure unless there was a major breakthrough since then, we are either seeing combined base stocks or dino's with some "better" base stock being added in order to meet the necessary viscosity index, Noack, Cleanliness Requirements, etc.