J300_201304 Engine Oil Viscosity Classification

This revision begins the process of extending the SAE Engine Oil Viscosity Classification system to lower high-temperature high-shear-rate (HTHS) viscosities by adding a new high-temperature viscosity grade – SAE 16 (>2.3 mPa·s HTHS) – to SAE J300. In addition, the minimum 100 °C kinematic viscosity (KV100) of the SAE 20 grade is raised from 5.6 mm²/s to 6.9 mm²/s. A formal request for this new grade was presented to the Engine Oil Viscosity Classification Task Force (EOVC) by the International Lubricant Standardization Advisory Committee (ILSAC) on September 21, 2011 as well as on earlier occasions by a number of individual original equipment manufacturers and oil companies. The benefit of establishing a new viscosity grade is to provide a framework for formulating lower HTHS viscosity engine oils in support of the ongoing quest of engine builders to improve fuel economy.

The minimum KV100 of the SAE 20 grade is increased from 5.6 mm²/s to 6.9 mm²/s for two reasons: (1) equipment manufacturers desire to narrow this range to ensure proper operation of hydraulically-actuated engine control devices which are sensitive to kinematic viscosity and (2) the lower portion of the KV100 range is not being utilized and is outside of the formulating range of oils with HTHS viscosity > 2.6 mPa·s. The new minimum value of 6.9 mm²/s was selected to provide the same KV100 range as a fraction of the minimum KV100 of the SAE 20 grade {(9.3-6.9)/6.9 = 0.35} as the current SAE 30 grade {(12.5-9.3)/9.3 = 0.34}. Raising the minimum KV100 is not expected to impact commercial SAE XW-20 lubricants in the marketplace.

The KV100 range of the SAE 16 grade overlaps that of the SAE 20 grade. This represents an historical departure from non-overlapping KV100 ranges in SAE J300. Allowing overlapping of these two grades was done to provide adequate formulating space for the new grade. Assignment of a single high-temperature viscosity grade to an engine oil with KV100 in the overlap region (6.9 – 8.2 mm²/s) is covered in Section 6 of this document.