oil weight for turbo'd car

Aluminum: Pistons, bearings, cases (heads & blocks).
Chromium: Rings, a trace element in steel.
Iron: Cylinders, rotating shafts, the valve train, and any steel part sharing the oil.
Copper: Brass or bronze parts, copper bushings, bearings, oil coolers, also an additive in some gasoline engine oils.
Lead: Bearings.
Tin: Bearings, bronze parts, piston coatings.
Molybdenum: Anti-wear additive, coating on some new rings (washes off as break-in occurs).
Nickel: Trace element in steel.
Manganese: Trace element, additive in gasoline.
Silver: Trace element.
Titanium: Trace element.
Potassium: Antifreeze inhibitor, additive in some oil types.
Boron: Detergent/dispersant additive, antifreeze inhibitors.
Silicon: Airborne dirt, sealers, gaskets, antifreeze inhibitors.
Sodium: Antifreeze inhibitors, additive in some gasoline engine oils.
Calcium: Detergent/dispersant additive.
Magnesium: Detergent/dispersant additive.
Phosphorus: Anti-wear additive.
Zinc: Anti-wear additive.
Barium: Detergent/dispersant additive.
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Molecular consistency:
Organic: Multiple molecular lengths
Synthetic: Molecular configuration uniform.
Why important: Lighter organic molecules tend to evaporate in the heat of the engine environment, eventually losing up to 25% of the volume. The loss of the shorter (and more volatile) length chains alters the original composition of the oil, affects its flow qualities and temperature rating. Synthetic oils are "designer molecules". There are no smaller chains with no tendancy to evaporate under heat (see flash point below).

Flash point:
Synthetic oil burns at almost twice the Ferenheit temperature as traditional oil. It remains consistent under extreme conditions with no degradation, thinning, boiling or evacation from bearing surfaces due to vaporization. Temperatures that would severely degrade traditional oil does not affect the lubrication qualities of synthetic. Jet aircraft engines will not run on standard oil. Synthetic is required. Race cars and other high performance engines used to use caster bean oil for its superior qualities. Synthetic has replace caster bean for high stress environments.

Saturation:
Traditional oils are poly-unsaturated while synthetic oils are fully saturated. Traditional oils will combine with crankcase polutants to form new and unpredictable molecular compounds, severely compromising the viscosity rating of the oil. Synthetic oil, being fully saturated (no open chain molecular sites able to bind with other organic compounds) and are not affected by the presense of pollutants, bypass gasses, fuel dilution, or water.

Consistency:
Traditional oils are treated with viscosity modifiers to produce the traditional variable viscosity ratings (example: 10W40). Synthetic oil is designed to be a particular rating by virtue of its molecular configuration. Usage does not modify its performance whereas traditional oil gradually loses their additives. 10W40 becomes 10W30 over time, for example. Changing the oil every 3000 miles is a must to maintain consistency when using traditional oil. The extended changes recommended, mostly marketing in my opinion, are too long to insure that the oil is maintaining its designed qualities, let alone guarantee the filter is not bypassing. Wait that long and change your oil. Notice how much smoother the engine becomes after the change. Not a good sign.

Engine Cleanliness:
Traditional oil will form compounds with crankcase polution and recipitate deposits to the case of the engine. Synthetic oils cannot combine with crankcase chemistry and thus will not form sludge or other undesirable compounds to clog oil passages or retain dirt inside the engine. Because synthetic oils will suspend dirt and other chemisty, those particles have a greater chance of being removed by the filter.

Cold Weather performance:
Synthetic oil will flow at -60º F. where traditional oil is wax. Starting a synthetic oil equiped engine when it is 0º F. is like starting traditional oil when it is 40º. The engine runs effortlessly verses exhibiting the typical stress when using traditional oil at low temperatures. Cold weather operation before warm up is not nice on engine bearings and cylinder walls when the oil viscosity approaches jello.

Dirt:
Use a 1 micron aircraft quality oil filter and you might never have to change synthetic oil as it doesn't degrade. Traditional oil would stay just as clean, but would be compromised over time by chemical bonding altering its structure (see saturation above).

Expensive car manufacturers are not stupid:
BMW and other premium cars insist that their engines be lubricated with sythetic oil. BMW warns owners to change oil ASAP if anything else is used. Using synthetic oil with regular changes provides the level of protection to the engine that maximizes its life. Certainly, it is more expensive up front, but the benefits will be realized in smoother performance, higher gas mileage, lower oil temperatures, greater resistance to damage if a coolant system failure raises the engine temperature, and ultimately a lower cost of operation. We spend $20,000+ for a car and complain about spending an additional $10 every three months to protect this expensive investment. It doesn't make sense. Quality maintenance is part of the expensive of a car.
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