Guess that we are not going to get any more facts and data
Originally Posted By: CATERHAM
Another example. Mobil obviously didn't designed their 0W-30 and 0W-50 race oils to be able to pump at -40 degrees. The 0W rating is just a result of using light high VI base oils to get a high VI finished oil which is what they want.
I'm not sure what Mobil were doing when they designed the 0W50...looks more like an oil for bragging rights on the VI than a proper race oil.
Seriously, a "50" with an HTHS of 3.8, which is really entry level 40 grade HTHS,and attainable with some schmick 30s.
Looks like they have purposely designed in temporary shear to get the VI unicorn effect, with nothing to back it.
From
here
Originally Posted By: CATERHAM
No at the top of my list are a low KV40 value for it's HTHSV, a high AW additive level and reasonable shear stability.
M1 racing 0W50
HTHS 3.8
KV40 100cst.
M1 0W40
HTHS 3.8
KV40 75 cst
Mobil X3000 5W40
HTHS 3.7 (as you've previously noted, 3.7 COULD be 3.7499999999, versus 3.8 of 3.75)
KV40 83cst.
Making a unicorn 40 weight that is really a mediocre 40 weight is a strange target.