For further details on the SAE J300’s significance, read “SAE J300: A Critical Standard”
The January 2015 revision of the Engine Oil Viscosity Classification Standard SAE J300 establishes two new high temperature viscosity grades: SAE 12 and SAE 8. These new grades reflect the continued industry push for lower viscosity engine oils to achieve higher fuel economy. They establish specifications to standardize new lower viscosity lubricants in the global marketplace.
SAE standardization sets a globally recognized definition of viscosity, with input from all major stakeholders, including OEMs, oil marketers and additives companies. SAE 12 and SAE 8 are critical additions to J300 as OEMs continue to develop new hardware that takes advantage of lower viscosity lubricants. SAE standardization establishes a recognizable and reliable framework for viscosity and labeling.
Parameters of SAE 12 and SAE 8
SAE 12 and SAE 8 are defined two high temperature viscosity measurements: kinematic viscosity at 100°C (KV100) and high temperature/high shear rate viscosity (HTHS), both of which are equally important to both passenger car and heavy duty diesel applications. While all high temperature viscosity grades have a minimum HTHS viscosity as defined in SAE J300, the potential for increased engine wear is greatest for ULV lubricants. HTHS is a measure of lubricant viscosity in an engine’s bearings during operation, where typical temperatures are 150°C and shear rates are 1 million reciprocal seconds. SAE 12 and SAE 8 set minimum HTHS viscosities at 2.0 and 1.7 mPa·s (cP), respectively, further establishing a critical framework in support of OEMs’ ongoing fuel economy pursuits. Important to note is that while the J300 standard formalizes these viscosity grades for use in both heavy duty diesel and passenger car applications, what qualifies as lower viscosity lubricants—including SAE 12 and SAE 8—are so far only applicable for passenger car hardware.
Another important component to the updated standard is the definition of minimum and maximum kinematic viscosity at 100°C (KV100) measurements for the new grades. Modern engines often utilize engine oils as hydraulic fluids, including hydraulically actuated fuel injectors and valve timing hardware. In order for these devices to work efficiently, the kinematic viscosity of lubricants must be controlled within a narrow window. The KV100 ranges of SAE 12 and SAE 8 overlap, offering adequate formulation space within the grades.
A Future of Efficiency
It doesn’t end here—there is a continued push toward lower and lower viscosities as OEMs continue to seek greater gains in fuel economy and efficiency. The J300 standard will remain flexible, reflective of market needs, and will continue to ensure the right oil for the right application—a consideration that is perhaps now more critical than ever.
