The only conventional oil that has group III added that I know of would be some 5w-20 motor oils that meet the ford or Honda specs and some 5w-30 PCMO. I read on this forum that Pennzoil 5w-20 is about 70% group III and 30% group II+ (not counting the additives) Chevron refers to the practice of adding group III oil to a group I or II or II+ as adding corrective stock. If you add some group III to some group I, II or II+ the viscosity index of the base oil will be raised and the NOACK rating of the oil will be lowered (improved). Also you will need fewer additives to be added to the oil. In some cases it can be cheaper to use a better base oil and fewer additives for a 5w-20 or 5w-30 motor oil than using a group I base oil. The oil would also most likely give better performance even with fewer additives. Any oil that is 100% group III would most likely be sold as a 100% synthetic so they could sell it for a much higher price.
The problem with blends is they carry the higher prices because they have the word "synthetic" on the bottle. I've found by researching you can usually find dinos that are as good or better than the blends, such as Chevron Supreme, and now from what I'm hearing the Pennzoil, for a much lower price. I guess if I wanted a blend, I'd just add a quart of M-1 to my dino at every oil change.
[ March 20, 2003, 09:57 PM: Message edited by: bottgers ]
Every 5w-20 has to pass a double length (160 hr) Sequence IIIF test in order to meet the Ford specs. So I'd say in general those are going to be better most petroleum oils.
I'd also look for oils that meet both SL and CF specifications - this means they have higher detergency than an oil that just meets the gas engine spec.
quote:Originally posted by bottgers:
I guess if I wanted a blend, I'd just add a quart of M-1 to my dino at every oil change.
I used to do this too, but will not again. Here's why...
M1 is a PAO based oil that was meant to work with a certain percentage of ester and amounts of additives (the high calcium comes to mind). With all the dino and different doses of additives that are possible, you are doing oil testing.
Please show us the UOA so we can see how it turns out.