Trying to find the link but Bob is the oil guy did a study on this stuff and found that it kills the anti foaming properties in the oil. That along with the potential for starvation if the oil is too heavy, this stuff usually belongs on the snake oil shelf.
That said I've not run it in anything that takes the 20w50 so I can't comment on that, but at least down here in Texas that's the stuff you put in a vehicle with a clapped out motor hoping some sucker will buy it.
