Different oils are categorized in-groups by the type of base stock they are made from. The base stock is just that. The bulk of the product you see in the bottle minus the additives that is mixed in to make the oil perform certain functions.

Group one oil:

These are the old high paraffin base oils. They are not used for modern engine oils anymore but can still be found in those little bottles of all-purpose household oil you buy at the hardware store for stuff like oiling door hinges.

Group two oils:

This is the standard petroleum base stock that all modem conventional petroleum oils are made from. Quality varies widely depending on where it was "dug up from". Even in "finished" form it can contain various amounts of paraffin (wax), impurities left over from refining and from the ground it came from! Chemically it is a hodge podge of different sized hydrocarbon molecules, not all of which "get along with each other" so to speak. The result of this is a product that produces sludge, varnish and mechanical wear as it ages and breaks down in service.

These oils have steadily been improved over the years as API services requirements have gotten stricter. However as modern engines pump more horsepower from smaller engines with less total oil sump capacity and the level of horsepower/torque transmitted though today's light weight fuel efficient drive trains continues to climb, lubricant manufacturers find that conventional petroleum oils really just cannot be improved any farther. Hence the move we see by automakers to synthetic fluids; both in engines and transmission/differentials. Combine that with the need to improve fuel economy and synthetic lubricants well know ability to do just that and you can see why "factory filled" with synthetic is becoming more and more common.

Group three oils:

Group three oils are petroleum oils that have been hydroisomerized, "hydro-cracked" as it is commonly called. The most stringent level of petroleum oil refining. Much of the paraffin and impurities have been removed and its performance on any number of industry tests is substantially better than it's group two cousins.

Although it is not made from a synthesized, engineered molecule and as such is not a true synthetic oil, it does offer a portion of the benefits you would expect from a true synthetic and in fact is usually sold and marketed as a 100% synthetic product.

In fact the vast majority of synthetic oils on the market are actually made from group three oils because of a lawsuit a few years ago between Mobil and Castrol that totally changed the synthetic oil industry. Because of this lawsuit the buying public has largely been duped into believing that these oils are actually a real synthetic.

Here's what happened. Mobil Inc. makers of Mobil One sued Castrol Inc. makers of Castrol Syntec, accusing them of marketing a hydro cracked petroleum oil as a synthetic-which they were!

Mobil Inc. felt that Castrol Inc. had pursued an unfair market advantage because group three based oils are much less expensive to manufacture than true synthetic oils yet Castrol was marketing Syntec as a 100% synthetic product: Castrol could make it for less, sell it for less and un-fairly under cut all it's competitors in the synthetic oil market with a oil that was not truly a synthetic product.

In the end though, Castrol convinced the court that group a three-based oil has been sufficiently refined that it should be able to be marketed along with true synthetic oils. Basically the court expanded the definition of synthetic to include group three based oils.

Because the synthetic oil market is the fastest growing part of the lubricants industry, manufactures are eager to jump up and grab the profits that having that sexy customer grabbing word synthetic on the bottle bring.

Group three oils have no where near the performance of true custom engineered synthetic oils, especially in tempeture extremes where the men get separated from the boys so to speak!

As was stated before, the vast majority of what is being sold as synthetic is now really group three petroleum based oils-and the public for the most part doesn't know the difference. But now you do!

Group four oils:

Polyalphaolefln and related olefin oligomers and olefin polymers. (Synthetic hydrocarbon) PAO's as they are commonly called are a true man made engineered base oil produced by catalytic reaction with various alpha olefin compounds.

PAO's are widely recognized as providing outstanding performance for many lubricant applications because of its very high viscosity index, a wide operational tempeture range and because it is thermal and shear stable.

PAO's also have low corrosivity and are compatible with mineral oils and the range of materials that engines and other machinery is manufactured from.

The molecular structure of PAO's are easily customized for use in all kinds of applications from automotive to industrial and are widely used in motor oils, gear lubes, high tempeture/extreme pressure greases, Compressor oils and hydraulic fluids.

Group five oils:

This group comprises all synthetic oils other than PAO's. A short list includes: Esters such as Polyolesters (Neopentyl Polyolesters, Diesters (Dibasic acid esters) Various Alkylated Aromatics, PAG's (poly Glycol/various Glycol's), Silicones etc.

This group of synthetics is primarily used for various industrial and aviation applications. Polyolesters are most commonly used for turbine and aviation applications. They are very thermally stable and ideally suited for very high tempeture use. Hence there use in such things as high temp greases, jet engines and gas turbines.

They have a very low coefficient of friction and are sometimes added in small amounts to mineral oils and other synthetic oils to lower the coefficient of friction of the finished product.

Diesters are most commonly used aviation and industrial compressor applications however because of the tremendous anti-scuffmg protection they offer. They are often added in small amounts to PAO based two-cycle oils as this feature is very beneficial to a two-cycle motor oil.

Diesters are shear stable, have good lubricity, detergency and are polar meaning they have an electrical charge that causes them to cling to metal surfaces-a desirable trait for most lubricants. Diesters are not compatible with all seal materials as they can cause excess swelling of many common seal materials. Because of this they are often added in small amounts to automotive PAO based oils to provide positive seal function.

Silicones offer wide tempeture performance and are sometimes used in compressor applications although this use has fallen out of favor in recent years. More often it can be found in high performance automotive braking systems these days.

Why Choose Synthetic Lubricants?

Motor oils are comprised of two parts, the base oil and additive package. The base oil comprises 80-90% of the oil by volume and the additives the remaining 10-20%. There are five groups of base oils stated above: Group I, II, III, IV and V. Groups I to III are refined from crude oil containing tars, asphalts, waxes ,aromatics and other "bad things". These crude oils are "cleaned up", to the extent possible, by hydrocracking and filtering. The group III base oils are the best of this genre. However, they still contain variably-sized molecules and some contaminants that can result in sludge, varnish and other deposits in your engine. Moreover, the quality of group III base oils vary greatly due to differences in the feedstocks and refining methods utilized.

Synthetic oils are group IV (PAOs) and group V (esters) base oils. These synthetic oils are "man-made" synthesized uniform molecular structures that significantly improve the efficiency and effectiveness of these oils relative to their petroleum oil competitors. More specifically, these oils have lower coefficients of friction, thermal (heat) and pour-point (cold weather performance) properties than do petroleum oils. Finally, synthetic oils have no waxes, tars, or other contaminants to sludge or varnish your engine.

While synthetic lubricants are initially more expensive, when you consider their extended oil and engine-life extension capabilities, in addition to their improved performance, then you have only one choice and that choice is synthetic oils.

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