Howard-
The group 4/5 means that the oil has both a group 4 (PAO) along with some group 5 (esters) in it. I heave read that the Series 3000 has a heavier add package and therefore goes longer, but I have yet to try personally. It also has a better add package; which means lower OXD, NOX better higher TBN, lower TAN and better soot control.
There Series 3000 has a more expensive, shear stable VI modifier that the 15w-40 does not.
And lastly there Ca and Mg are higher then their 15w-40. Both are good oils. Just look at your application. I will be trying their Series 3000 this spring and comparing it to there 15w-40 which I currently use. I know that the Ca level if over 4,000 ppm!
To find a list go to BITOG and do some seaching. Basically it comes down to you get what you pay for. Don’t except a group 5 to be the same price and performance as a 1 or 2…and so on.
