Originally Posted By: Quattro Pete
The reason you don't see synthetic SAE30 oils is that by their nature, synthetics have much higher viscosity index, and as such can easily meet the 10w test, and if they can, then they have to be classified as such.
No, if they are Newtonian, they can label as a straight weight...they can dual label it as a multigrade too if it meets the specs.
If they are non-newtonian, i.e. have polymer, then they must label it as the lowest "w" that it meets.
http://paservice.it/wp-content/uploads/2013/06/J300_201304.pdf
Quote:
Most oils will meet the viscosity requirements of at least one of the W grades. Nevertheless, consistent with historic practice, any Newtonian oil may be labeled as a single-grade oil (either with or without a W). Oils which are formulated with polymeric viscosity index improvers for the purpose of making them multiviscosity-grade products are non-Newtonian and must be labeled with the appropriate multiviscosity grade (both W and high-temperature grade). Since each W grade is defined on the basis of maximum cranking and pumping viscosities as well as minimum kinematic viscosities at 100 °C, it is possible for an oil to satisfy the requirements of more than one W grade. In labeling either a W grade or a
multiviscosity grade oil, only the lowest W grade satisfied may be referred to on the label. Thus, an oil meeting the requirements for SAE grades 10W, 15W, 20W, 25W, and 30 must be referred to as an SAE 10W-30 grade only.
As to the Amsoil offering, it's maybe applicable if there's no wet clutch requirement.