Understanding Differences in Synthetics

[buster]

Link

Quote:
"How does a Group III engine oil compare to a Group IV oil in its cleaning ability?


Quote:
However, from an academic point of view, I would expect the cleaning ability of a Group III and a PAO to be similar (generally poor).


Btw, for all the PAO purists, Group III's have better solvency than PAO's and Shell has stated this many times. Some of their racing oisl were actually Group III based for F1. Blends are the best.

 

[Quattro Pete]

Originally Posted By: buster
Btw, for all the PAO purists, Group III's have better solvency than PAO's and Shell has stated this many times.

Yup. This is a well known fact. That's why it's not possible to have a 100% PAO oil. You need something else (either mineral oil or ester) to be used as additive carrier.

 

[MolaKule]

Quote:
...However, from an academic point of view, I would expect the cleaning ability of a Group III and a PAO to be similar (generally poor). Again, academically, I would expect less risk of seal issues, etc., when switching from a Group III oil (as opposed to a Group I oil) to a PAO, as the Group III oil and PAO are chemically similar.

Ester synthetics have a higher degree of solvency than Group II, III or PAO base oils. This means they will dissolve additives and deposits more readily and may cause some seals to swell slightly. They also can remove some paints. These characteristics (other than paint removal) can be beneficial, so some oil formulators will add small amounts of ester base oils into their synthetic (Group III and PAO) formulations to improve these properties.


I have been trying to tell people for many years that it is the performance of the complete formulation that matters.

This is what happens when people try to fixate on one component of a fully formulated oil without understanding the interaction of fully formulated chemistry package(s).

What we (formulators) attempt to do is to develop a base oil mix that will play well with the additives and perform to specification.

The cleaning ability of the fully formulated package is primarily dependent upon the detergent and dispersant chemistries with the base oils playing a secondary role.

 

[MolaKule]

Tom has some good info on synthetic lubes:

Esters in Synthetics

Synthethics Overview

 

[Tom NJ]

Originally Posted By: MolaKule

I have been trying to tell people for many years that it is the performance of the complete formulation that matters.

This is what happens when people try to fixate on one component of a fully formulated oil without understanding the interaction of fully formulated chemistry package(s).

What we (formulators) attempt to do is to develop a base oil mix that will play well with the additives and perform to specification.

The cleaning ability of the fully formulated package is primarily dependent upon the detergent and dispersant chemistries with the base oils playing a secondary role.


+1 !!!

Tom NJ

 

[buster]

Originally Posted By: MolaKule
Quote:
...However, from an academic point of view, I would expect the cleaning ability of a Group III and a PAO to be similar (generally poor). Again, academically, I would expect less risk of seal issues, etc., when switching from a Group III oil (as opposed to a Group I oil) to a PAO, as the Group III oil and PAO are chemically similar.

Ester synthetics have a higher degree of solvency than Group II, III or PAO base oils. This means they will dissolve additives and deposits more readily and may cause some seals to swell slightly. They also can remove some paints. These characteristics (other than paint removal) can be beneficial, so some oil formulators will add small amounts of ester base oils into their synthetic (Group III and PAO) formulations to improve these properties.


I have been trying to tell people for many years that it is the performance of the complete formulation that matters.

This is what happens when people try to fixate on one component of a fully formulated oil without understanding the interaction of fully formulated chemistry package(s).

What we (formulators) attempt to do is to develop a base oil mix that will play well with the additives and perform to specification.

The cleaning ability of the fully formulated package is primarily dependent upon the detergent and dispersant chemistries with the base oils playing a secondary role.


+1

 

[ARCOgraphite]

If any wants it, I think I have a ~10YO paper from ELF talking about the performance formulation of synthetic oil for F1; IIRC in specific racing appllications the best performer was found to be a blend after time and many "failures" in situ - but know the "mineral oil" mix in fix can be as varied as the stars itself and can be "vintage" dependent.
Remember when non-additised SA lubes had to do the jobs of the veritable chem kit we run today? Oil field geology, paraffin vs naphthenes, Tower Cuts, Polar heads, blah blah, ya know?