Synthetic Oil

Synthetic oil is a lubricant consisting of chemical compounds that are artificially made (synthesized). Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be synthesized from other raw materials. Synthetic oil is used as a substitute for lubricant refined from petroleum when operating in extremes of temperature, because, in general, it provides superior mechanical and chemical properties to those found in traditional mineral oils. Aircraft jet engines, for example, require the use of synthetic oils, whereas aircraft piston engines do not. Synthetic lubricants are also used in metal stamping to provide environmental and other benefits when compared to conventional petroleum and animal fat based products. These products are also referred to as "non-oil" or "oil free".

Advantages

The technical advantages of synthetic motor oils include:

• Better low- and high-temperature viscosity performance at service temperature extremes
• Better (higher) Viscosity Index (VI)
• Better chemical and shear stability
• Decreased evaporative loss
• Resistance to oxidation, thermal breakdown, and oil sludge problems
• Possibility to extended drain intervals, with the environmental benefit of less used oil waste generated
• Improved fuel economy in certain engine configurations
• Better lubrication during extreme cold weather starts
• Possibly a longer engine life
• Superior protection against "ash" and other deposit formation in engine hot spots (in particular in turbochargers and superchargers) for less oil burnoff and reduced chances of damaging oil passageway clogging.
• Increased horsepower and torque due to less initial drag on engine
• Improved Fuel Economy (FE) - from 1.8% to up to 5% has been documented in fleet tests

Disadvantages

The disadvantages of synthetic motor oils include:

• Substantially more expensive (per volume) than mineral oils.
• Potential decomposition problems in certain chemical environments (predominantly in industrial use.)

http://en.wikipedia.org/wiki/Synthetic_oil