Originally Posted By: Colt
I have one oil change of Toyota 0w20 SM left and like the fact it has a lot of moly.
I haven't been reading about the difference between the SN and SM.Only that the SN has very little moly.
How is the SN vs the SM?
Which is better?
Well, SN is simply a better, more advanced spec than SM. Asking if SN is better than SM is in some sense not too different than asking if SM is better than SF.
Infineum, coowned by ExxonMobil and Shell, invented, patented, and makes the trinuclear moly. About 50 - 100 ppm of moly from the trinuclear-moly molecules (which have three Mo atoms per molecule) results in the maximum reduction in fuel economy and maximum protection against engine wear. It's a much, much better formulation of moly than it was used in the SM formulation of Toyota 0W-20 (Akeda S-100 moly from Asaki Denka Kogyo K.K. of Japan), which was dumped into the oil in extremely high concentrations (600 ppm or so) with the hope that it would reduce the fuel economy more. 75 ppm of trinuclear moly gives much better performance than poorly formulated moly such as the Akeda S-100 moly. While there is no proof that Toyota 0W-20 uses trinuclear moly, this is what makes sense most, as ExxonMobil ownes Infineum and Toyota would absolutely not settle for anything less than the best fuel economy, as their main marketing strategy is to crate the most fuel-efficient cars.
Is Toyota 0W-20 better than M1 AFE 0W-20? I think so, but of course, you never know. I think, as CATERHAM said, it definitely has higher fuel-efficiency (less friction) than M1 AFE 0W-20 not only because of the really high viscosity index (216) but also the quality friction modifiers and base oil, along with Toyota's pressure to make the most fuel-efficient oil possible.
The base oil used in it would have to be at least Group III+ like in Sustina because of the extremely high viscosity index. Chances are that ExxonMobil threw in at least some Group IV/V in it. Also remember that Toyota specifies 10,000-mile OCI on its new cars with this oil, meaning that the base oils used in Toyota 0W-20 would have to be really high quality in order to withstand oxidation in prolonged OCIs. Group IV certainly withstands the oxidation most, followed by Group III+.