If it performs like a SAE 0 motor oil at the colder temperature, then it will receive the SAE 0W viscosity grade. Basically, as shown by the chart, when the oil is reduced to a colder temperature it is measured for performance factors. Now if you look at the table labeled Winter or “W” Grades, you can get valuable information on how the W or winter grade viscosities are measured. This is why the cSt centistokes numbers more accurately show oil viscosity. An oil that is 9.2 cSt will be nearly the same viscosity as an oil that is 9.3 cSt, yet one is an SAE 20 and the other is an SAE 30. You’ll see the ranges for cSt compared to SAE numbers. The table at the right, SAE Viscosity Chart (High Temp), shows the equivalents for cSt and SAE viscosity numbers. You’ll see these numbers used often for industrial lubricants such as compressor or hydraulic oils. Another system takes more accurate numbers into account known as cSt abbreviated for centistokes. But you have to draw the line somewhere and that’s how the SAE system is designed. Technically speaking these oils will be close to the same viscosity even though one is an SAE 20 and the other an SAE 30. Then another oil is timed to be an SAE 20 on the high side not quite breaking into the SAE 30 numbers. For example, an oil is barely an SAE 30 having a time that puts it on the very low side. Occasionally it is possible for an oil to barely fall into one viscosity range. If an oil flows through faster being thinner/lighter then it will wind up in a low number range such as SAE 10 or SAE 20 for example. Thicker or heavy viscosity oils will take longer to flow through the orifice in the viscometer and end up in higher number ranges such as SAE 50 or SAE 60 for example. Using a table they determine SAE viscosity based on different ranges. See the Tables to the right below for more information.īasically to determine non-winter grade viscosity using a viscometer a measured amount of oil at 100° C is allowed to flow through an orifice and timed. There is a scale for the W, or winter viscosity grades and, depending on which grade is selected, testing is done at different temperatures. Simply put, these tests are done with a different temperature system. Obviously, cold temperature or Wratings are tested differently than regular SAE viscosity ratings. Less dry running means much less engine wear. The quicker the oil flows cold, the less dry running. The advantages of a low W viscosity number is obvious. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. The difference is when the viscosity is tested at a much colder temperature. In other words, a SAE 30 motor oil is the sameviscosity as a 10w-30 or 5W-30 at 210° (100° C). The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Coldertemperature. What does a 5W-30 do that an SAE 30 won’t? "Dynamic Viscosities of (Methyl Acetate or Methanol) with (Ethanol, 1-Propanol, 2-Propanol, 1-Butanol, and 2-Butanol) at 298.15 K"įood Processing Technology: Principles and Practice (3rd ed.OK. The rheological properties of ketchup as a function of different hydrocolloids and temperature The Viscosities of Iodine Pentafluoride and Ditellurium Decafluoride Industrial & EngineeringĮffect of moisture content on the viscosity of honey at different temperatures "Viscosity of Glycerol and Its Aqueous Solutions". Journal of Chemical & Engineering Data. 40 (1): 136–140.įood Processing Technology: Principles and Practice (3rd ed.) "Viscosity and Density of Binary Liquid Mixtures of Hydrocarbons, Esters, Ketones, and Normal Chloroalkanes". Densities and viscosities of binary mixtures of 1-propanol and 2-propanol with acetonitrileĬRC Handbook of Chemistry and Physics, 99th Edition
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