Originally Posted By: oil_film_movies
Originally Posted By: Gokhan
(2) High moly (> 600 ppm) isn't for meeting any specs but for fuel economy.
Not true. High moly supports an AW cold tribofilm before ZDDP takes over under high heat and pressure. FM effects max out at under 100 ppm. This is why most oils don't go over 100 ppm of moly, since those smaller amounts max out the FM benefits at those low levels. (Mazda oil bottles state this directly on the label, and I read some technical articles years ago that said it.)
So why does Japanese oil use so much moly? They are concerned about the thinner (low HTHS) oils spending too much time in mixed and boundary lubrication regimes, and offer the extra moly to boost AW performance where pressures are too low to form ZDDP layers. Keep in mind Toyota has an eye on GF6 goals, with thinner and thinner oils that need better mixed-boundary performance. Other oil makers accomplish this with mostly esters sliming the surface, but lots of moly does it too, so they chose moly. (Think something similar to Castrol Magnatec's ester approach, but more of it as oil thins out even more in the future.)
Idemitsu 5W-30: 1,000 ppm moly (link)
So much with the conjecture that the high moly is to make up for the low HTHSV.
Nevertheless, thick-oil-is-good-and-thin-oil-is-bad guys will never stop making such conjectures.
Originally Posted By: Gokhan
(2) High moly (> 600 ppm) isn't for meeting any specs but for fuel economy.
Not true. High moly supports an AW cold tribofilm before ZDDP takes over under high heat and pressure. FM effects max out at under 100 ppm. This is why most oils don't go over 100 ppm of moly, since those smaller amounts max out the FM benefits at those low levels. (Mazda oil bottles state this directly on the label, and I read some technical articles years ago that said it.)
So why does Japanese oil use so much moly? They are concerned about the thinner (low HTHS) oils spending too much time in mixed and boundary lubrication regimes, and offer the extra moly to boost AW performance where pressures are too low to form ZDDP layers. Keep in mind Toyota has an eye on GF6 goals, with thinner and thinner oils that need better mixed-boundary performance. Other oil makers accomplish this with mostly esters sliming the surface, but lots of moly does it too, so they chose moly. (Think something similar to Castrol Magnatec's ester approach, but more of it as oil thins out even more in the future.)
Idemitsu 5W-30: 1,000 ppm moly (link)
So much with the conjecture that the high moly is to make up for the low HTHSV.
Nevertheless, thick-oil-is-good-and-thin-oil-is-bad guys will never stop making such conjectures.