viscosity matters
What Is Viscosity ?
Viscosity is a physical property of a fluid defined as its resistance to flow and is highly dependent upon temperature . Lubricant viscosity is closely related to its ability to reduce friction . Usually the lowest viscosity lubricant that still forces two moving surfaces apart from one another is desired . If a lubricant is too thick , having a consistency like honey , it requires a large amount of energy to pump or move . If it is too thin , the surfaces will rub , friction will increase , and wear will result .
It is well known that the viscosity of oil increases ( gets thicker ) as temperatures decrease and decreases ( gets thinner ) as temperatures increase . The most common method for measuring the viscosity of lubricants is the Kinematic Method and is performed by timing a known volume of oil as it flows through a calibrated capillary tube under gravity .
What Is Viscosity Index ?
The Viscosity Index ( VI ) of an oil relates to the change in viscosity for a given change in temperature . VI is calculated using the viscosities at 40 ° C and 100 ° C . A high VI lubricant will have a smaller change in viscosity with a given change in temperature than one with a low VI .
A viscosity index improver ( VII ) is a polymer that is used to decrease the viscosity-temperature dependence of lubricants . VIIs allow for lighter base oils to be used as they make the oil “ thicker ” at higher temperatures to prevent metal surfaces from rubbing together . Meanwhile , the oil remains “ thinner ” at lower temperatures , allowing for easier cranking and pumpability throughout the engine .
Multi-Viscosity Oils
Lubricants containing a VII are labeled as multigrades or multi-viscosity oils . An example is an SAE 15W-40 where the “ 15W ” represents the winter grade performance and the “ 40 ” represents the high temperature performance .
One differentiating characteristic of a high-quality engine lubricant is its ability to “ stay-in-grade ” during its useful life . Soot particles can conglomerate and thicken oil over time . High-quality lubricants contain advanced detergency and dispersancy chemistry to prevent soot particles from binding together . A lubricant can also thin ( lose viscosity ) and allow excessive wear if its VII fails . This is commonly referred to as “ shearing ,” as in the shearing of long chain molecules . It can result in temporary or permanent viscosity loss .
Why FS SUPREX GOLD ® ESP Outperforms
FS Suprex Gold ESP Premium HDEO utilizes a unique soot-dispersing technology that diffuses soot to reduce oil thickening . It also uses the latest VII chemistry to offer exceptional shear stability and stay-ingrade viscosity well beyond provisions of the API CK-4 performance category . Both characteristics are important for long-lasting protection and extended drain intervals .
For more information regarding suprex gold esp or other highquality fs lubricants , see your fs lubricant sales specialist today .