A good way to judge Group 3 by different manufacturers is by it's viscosity index since the higher it is, the less "bad stuff" is in it, like napthenic molecules and some other molecules. I have print outs at home from a few years ago giving the physical properties of Mobil's Group 1, 2, 3, 4 and 5 basestocks but can no longer find the Group 1, 2, and 3 data online to give you the link.
There are so many ingredients that can be used in synthetic motor oils that affect performance that discussing what we think the basestocks are should be just for fun. Here's a case in point. Is it better to have PAO as the sole basestock and have the additives solubized in Group 1 OR have top notch Group 3 as the primary basestock and use Group 5 to both solubize the additives and boost performance in several important areas? Surely the answer to that question with one relative concentration of Group 3 to 5 could be different to the answer for a different relative concentration between Groups 3 and 5. Throw in the different antioxidant types and concentrations and we already have a very complicated mixture. We have not even got to the other additives and different PAOs available and all bets are off already. Then there is the synergy and antagonism that goes on between different ingredients. Only testing will reveal the performance differences.
Note: all synthetics need a fluid added that solubizes the additives. As far as I know, there's no such thing as a motor oil with nothing but Group 3 and/or Group 4 and additives. What's used to solubize the additives can be either performance descreasing or performance increasing, depending on what's used.
There are so many ingredients that can be used in synthetic motor oils that affect performance that discussing what we think the basestocks are should be just for fun. Here's a case in point. Is it better to have PAO as the sole basestock and have the additives solubized in Group 1 OR have top notch Group 3 as the primary basestock and use Group 5 to both solubize the additives and boost performance in several important areas? Surely the answer to that question with one relative concentration of Group 3 to 5 could be different to the answer for a different relative concentration between Groups 3 and 5. Throw in the different antioxidant types and concentrations and we already have a very complicated mixture. We have not even got to the other additives and different PAOs available and all bets are off already. Then there is the synergy and antagonism that goes on between different ingredients. Only testing will reveal the performance differences.
Note: all synthetics need a fluid added that solubizes the additives. As far as I know, there's no such thing as a motor oil with nothing but Group 3 and/or Group 4 and additives. What's used to solubize the additives can be either performance descreasing or performance increasing, depending on what's used.
