Fuel Economy and Synthetics

By Tom Schaefer

"The largest effect motor oils have on fuel economy is through viscosity, followed by friction modification. Lower viscosity oils can save a few percent in fuel consumption when measured by industry standard engine tests, regardless of whether the base oil is synthetic or mineral. Friction modifiers will kick in a little more, but the combined effect is rarely more than 3% compared to 10W-30s or 40s.

Synthetics can play a role in fuel economy in three ways:

1. Synthetics are generally less volatile and have higher VIs than mineral oils, so you can make thinner oils without sacrificing oil consumption, catalyst damage, and HTHS viscosity. In other words, you can make better low viscosity motor oils from synthetic base oils than from mineral base oils.

2. Synthetics are generally more oxidatively stable than mineral oils, so the oil can retain its lower viscosity longer. This means the favorable effect from lower viscosity may last longer and therefore save more fuel over time.

3. Some synthetics utilize polar base oils that can lower friction and improve lubricity. This makes them behave like a friction modifier, although they may compete to some extent with friction modifier additives and therefore not add much.

As for measuring the fuel efficiency, only carefully controlled engines tests such as those used for GF-4 certification are sensitive and repeatable enough to see the small contribution oils provide. The average consumer has far too many variables to reliably measure or even see oil related fuel savings, such as city/highway mix, road conditions, tire pressure, driving style, engine condition, fuel brand and dispensing accuracy, sensor condition, temperature, wind, humidity, etc. I plotted my MPG for 13 years on the same car and same gas, and the results varied from 16 to 29 MPG, with 95% of the data being +-15% from the mean. Imagine trying to see a 2% improvement in a plot that swings that wildly. I have to giggle when I hear people report a 5 or 10% improvement after one tank of gas. Such testimonials are worthless.

Bottom line, you will never know exactly how much gas you are saving from your motor oil, nonetheless the contribution from synthetics, but you can be sure that lower viscosity oils will save some fuel and a good synthetic a little more." - Work Cited: Tom Schaefer

Synthetic Lubricants

By Tom Schaefer


For most products, the word “Synthetic” is often a negative term, implying cheap, imitation, or artificial - just not up to the “real thing”. In the world of lubrication, however, just the opposite is true. Synthetic lubricants by virtually all measures are distinctly superior to their petroleum counterparts. And while they may be more expensive to buy, their cost saving performance benefits make them less expensive to use. In this market, Synthetic clearly means Premium.


Some definitions

Defining the term “synthetic lubricant” is becoming more controversial these days, but in general it refers to a lubricant or grease whose basestock has been manufactured by chemical synthesis or organic reaction, as opposed to being extracted or refined from naturally occurring oils. In many respects synthetics represent a different approach altogether from conventional petroleum based oils in that their molecular structures are custom designed and tailored to meet specific performance targets. To appreciate this concept better, we need to understand something about the composition of lubricants and how they work.

Most lubricants consist of a basestock and various additives selected to improve or supplement the basestocks’ performance. The basestock is the primary component, usually 70 to 99% of the finished oil or grease, and its properties play a vital role. To a great degree the structure and stability of the basestock dictate the flow characteristics of the oil and the temperature range in which it can operate, as well as many other vital properties such as volatility, lubricity, and cleanliness. Additives enhance these properties or impart new ones, such as improving stability at both high and low temperatures, modifying the flow properties, and reducing wear, friction, rust and corrosion. The basestocks and additives work together and must be carefully selected and balanced to allow the finished oil to do its intended job, which includes protecting moving parts from wear, removing heat and dirt, preventing rust and corrosion, and improving energy efficiency. Since the basestock is the dominate component with the most important role, one obvious way to make a better oil is to start with a better basestock. That is exactly what synthetic oils endeavor to accomplish.

Conventional petroleum basestocks or mineral oils begin with crude oil, a mixture of literally hundreds of different molecules derived from the decomposition of prehistoric plant and animal life. The lighter more volatile components of crude oil are stripped away to make gasoline and other fuels, and the heaviest components are used in asphalt and tar. It’s the middle cuts that have the right thickness or viscosity for lubricants, but first they must be cleaned up; undesirable components such as waxes, unsaturated hydrocarbons, and nitrogen and sulfur compounds must be removed. Modern processing techniques do a pretty good job of removing these undesirable components, good enough for well over 90% of the world’s lubricant applications, but they cannot remove all of the bad actors. And it’s these residual “weak links” that limit the capabilities of mineral oils, usually by triggering breakdown reactions at high temperatures or freezing up when cold. These inherent weaknesses limit the temperature range in which mineral oils can be used and shorten the useful life of the finished lubricant.


Synthetic basestocks, on the other hand, start from relatively pure and simple chemical building blocks which are then reacted together or synthesized into new, larger molecules. The resulting synthetic basestock consists only of the pre-selected molecules and has no undesirable weak links that inhibit performance. This ability to pre-select or design specific ideal molecules tailored for a given job, and then create those molecules and only those molecules, opens a whole new world for making superior basestocks for lubricants. In fact, the entire formulation approach is different: instead of trying to clean up a naturally occurring chemical soup to acceptable levels with a constant eye on cost, the synthetic molecular engineer is able to focus on optimum performance in a specific application with the knowledge that he can build the necessary molecules to achieve it. Since synthetics cost considerably more than petroleum based basestocks, they are generally reserved for problem applications where conventional oils fail, or where the efficiency benefits of synthetics recoup the initial cost.

A bit of history

The use of synthetic basestocks to solve lubrication problems is not new. Various synthetics were developed and used extensively during the second world war to prevent the oil from freezing in the army tanks during winter combat. After the war, synthetics were found to be essential for the new jet engines which ran too hot for mineral oils, causing them to burn off rapidly and leave deposits. These jet engines also had to be able to restart at high altitudes where temperatures were often -50°F, so the oil had to be pumpable at very low temperatures as well as surviving the searing temperatures within the engine. Indeed the modern jet engine would not exist today if not for the simultaneous development of synthetic basestock technology in the 1950s, and today virtually every jet engine in the world operates exclusively on synthetic lubricants.

During the 1960s and 70s, synthetics moved steadily into severe industrial applications where they solved high temperature deposit problems with air compressors and oven conveyor chains, and low temperature flow problems in arctic climates. New synthetic chemistries emerged to meet and match every problem industrial users could create, and there were many! Gradually these expensive high-tech synthetic lubricants were entering the mainstream and taken seriously as they proved their ability to save money through reduced downtime, less maintenance costs, extended equipment life, lower energy consumption, and higher productivity. Focus shifted to the total cost of lubrication, not just the cost of the lubricant, and synthetics were often the winners.

Synthetic automobile motor oils were introduced in the early 1970s with such fantastic performance claims that they initially turned the auto manufacturers and oil companies against the new unproven products. While most claims were directionally valid, the level of improvements were often exaggerated to the point of fostering a “snake oil” reputation. Over the ensuing years, the true benefits of synthetic motor oils were identified and quantified to industry satisfaction and include better high temperature stability, improved low temperature flow characteristics, lower volatility, increased fuel efficiency, and extended life capability. Today car manufacturers and oil companies alike readily acknowledge the superior performance of synthetic motor and gear oils, especially in fleet or severe duty usage. For the average car owner, however, driving conditions are mild enough for conventional mineral oils to work satisfactorily, which raises the question of whether synthetic benefits are really needed for passenger cars and worth the higher price tag. In most cases the combined improvements will repay the higher initial cost, especially in severe duty applications, but since these improvements are not readily perceived by the driver, market penetration remains only a few percent after more than thirty-five years of active marketing. Synthetic motor oil usage will likely accelerate in future years as engine builders exploit the benefits in new engine design and ratchet up oil performance through tighter specifications.

In summary

Today the use of synthetic lubricants is accepted, widespread, and rapidly growing as their capability and cost efficiency benefits become better known worldwide. Jet aircraft use synthetic oils in the engines, hydraulic systems, instruments and landing gears; compressors use synthetics in the crankcase and cylinders; refrigeration systems use synthetics with the new environmentally friendly refrigerants; truck fleets use synthetics in the engine, transmission, and gear box; and the list goes on and on. Wherever a problem exists with mineral oils or a potential for improved cost efficiency uncovered, there is a synthetic lubricant ready and able to step in and lower the cost of total lubrication.

ESTERS IN SYNTHETIC LUBRICANTS

By Tom Schaefer

In the simplest terms, esters can be defined as the reaction products of acids and alcohols. Thousands of different kinds of esters are commercially produced for a broad range of applications. Within the realm of synthetic lubrication, a relatively small but still substantial family of esters have been found to be very useful in severe environment applications. This paper shall provide a general overview of the more common esters used in synthetic lubricants and discuss their important benefits and utilities.

Esters have been used successfully in lubrication for more than 60 years and are the preferred stock in many severe applications where their benefits solve problems or bring value. For example, esters have been used exclusively in jet engine lubricants worldwide for over 50 years due to their unique combination of low temperature flowability with clean high temperature operation. Esters are also the preferred stock in the new synthetic refrigeration lubricants used with CFC replacement refrigerants. Here the combination of branching and polarity make the esters miscible with the HFC refrigerants and improves both low and high temperature performance characteristics. In automotive applications, the first qualified synthetic crankcase motor oils were based entirely on ester formulations and these products were quite successful when properly formulated. Esters have given way to PAOs in this application due to PAOs lower cost and their formulating similarities to mineral oil. Nevertheless, esters are often used in combination with PAOs in full synthetic motor oils in order to balance the effect on seals, solubilize additives, reduce volatility, and improve energy efficiency through higher lubricity. The percentage of ester used can vary anywhere from 5 to 25% depending upon the desired properties and the type of ester employed.

The new frontier for esters is the industrial marketplace where the number of products, applications, and operating conditions is enormous. In many cases, the very same equipment which operates satisfactorily on mineral oil in one plant could benefit greatly from the use of an ester lubricant in another plant where the equipment is operated under more severe conditions. This is a marketplace where old problems or new challenges can arise at any time or any location. The high performance properties and custom design versatility of esters is ideally suited to solve these problems. Ester lubricants have already captured certain niches in the industrial market such as reciprocating air compressors and high temperature industrial oven chain lubricants. When one focuses on temperature extremes and their telltale signs such as smoking and deposits, the potential applications for the problem solving ester lubricants are
virtually endless.


Ester Chemistry

In many ways esters are very similar to the more commonly known and used synthetic hydrocarbons or PAOs. Like PAOs, esters are synthesized from relatively pure and simple starting materials to produce predetermined molecular structures designed specifically for high performance lubrication. Both types of synthetic basestocks are primarily branched hydrocarbons which are thermally stable, have high viscosity indices, and lack the undesirable and unstable impurities found in conventional petroleum based oils. The primary structural difference between esters and PAOs is the presence of multiple ester linkages (COOR) in esters which impart polarity to the molecules. This polarity affects the way esters behave as lubricants in the following ways:

1) Volatility: The polarity of the ester molecules causes them to be attracted to one another and this intermolecular attraction requires more energy (heat) for the esters to transfer from a liquid to a gaseous state. Therefore, at a given molecular weight or viscosity, the esters will exhibit a lower vapor pressure which translates into a higher flash point and a lower rate of evaporation for the lubricant. Generally speaking, the more ester linkages in a specific ester, the higher its flash point and the lower its volatility.

2) Lubricity: Polarity also causes the ester molecules to be attracted to positively charged metal surfaces. As a result, the molecules tend to line up on the metal surface creating a film which requires additional energy (load) to wipe them off. The result is a stronger film which translates into higher lubricity and lower energy consumption in lubricant applications.

3) Detergency/Dispersency: The polar nature of esters also makes them good solvents and dispersants. This allows the esters to solubilize or disperse oil degradation by-products which might otherwise be deposited as varnish or sludge, and translates into cleaner operation and improved additive solubility in the final lubricant.

4) Biodegradability: While stable against oxidative and thermal breakdown, the ester linkage provides a vulnerable site for microbes to begin their work of biodegrading the ester molecule. This translates into very high biodegradability rates for ester lubricants and allows more environmentally friendly products to be formulated.

Another important difference between esters and PAOs is the incredible versatility in the design of ester molecules due to the high number of commercially available acids and alcohols from which to choose. For example, if one is seeking a 6 cSt synthetic basestock, the choices available with PAOs are a straight cut 6 cSt or a “dumbbell” blend of a lighter and heavier PAO. In either case, the properties of the resulting basestock are essentially the same. With esters, literally dozens of 6 cSt products can be designed each with a different chemical structure selected for the specific desired property. This allows the “ester engineer” to custom design the structure of the ester molecules to an optimized set of properties determined by the end customer or application. The performance properties that can be varied in ester design include viscosity, viscosity index, volatility, high temperature coking tendencies, biodegradability, lubricity, hydrolytic stability, additive solubility, and seal compatibility.

As with any product, there are also downsides to esters. The most common concern when formulating with ester basestocks is compatibility with the elastomer material used in the seals. All esters will tend to swell and soften most elastomer seals however, the degree to which they do so can be controlled through proper selection. When seal swell is desirable, such as in balancing the seal shrinkage and hardening characteristics of PAOs, more polar esters should be used such as those with lower molecular weight and/or higher number of ester linkages. When used as the exclusive basestock, the ester should be designed for compatibility with seals or the seals should be changed to those types which are more compatible with esters.

Another potential disadvantage with esters is their ability to react with water or hydrolyze under certain conditions. Generally this hydrolysis reaction requires the presence of water and heat with a relatively strong acid or base to catalyze the reaction. Since esters are usually used in very high temperature applications, high amounts of water are usually not present and hydrolysis is rarely a problem in actual use. Where the application environment may lead to hydrolysis, the ester structure can be altered to greatly improve its hydrolytic stability and additives can be selected to minimize any effects.

The following is a discussion of the structures and features of the more common ester families used in synthetic lubrication.

Diesters

Diesters were the original ester structures introduced to synthetic lubricants during the second World War. These products are made by reacting monohydric alcohols with dibasic acids creating a molecule which may be linear, branched, or aromatic and with two ester groups. Diesters which are often abbreviated DBE (dibasic acid esters) are named after the type of dibasic acid used and are often abbreviated with letters. For example, a diester made by reacting isodecyl alcohol with adipic acid would be known as an “adipate” type diester and would be abbreviated “DIDA” (Diisodecyl Adipate).

Adipates are the most widely used diesters due to their low relative cost and good balance of properties. They generally range from about 2.3 to 5.3 cSt at 100°C and exhibit pour points below -60°C. The viscosity indices of adipates usually run from about 130 to 150 and their oxidative stability, like most of the diesters, are comparable to PAOs. The primary difference between adipate diesters and PAOs is the presence of two ester linkages and the associated polarity benefits outlined previously. The most common use of adipate diesters is in combination with PAOs in numerous applications such as screw compressor oils, gear and transmission oils, automotive crankcase oils, and hydraulic fluids. Adipates are also used as the sole basestock where biodegradability is desired or high temperature cleanliness is critical such as in textile lubricants and oven chain oils.

Azelates, sebacates, and dodecanedioates are similar to adipates except that in each case the carbon chain length (backbone) of the dibasic acid is longer. This “backbone stretching” significantly increases viscosity index and improves the lubricity characteristics of the ester while retaining all the desirable properties of the adipates. The only downside to these types of diesters is price which tends to run about 50 - 100+% higher than adipates at the wholesale level. This group of linear DBEs are mainly used in older military specifications and where the lubricity factor becomes an important parameter.

Phthalates are aromatic diesters and this ring structure greatly reduces the viscosity index (usually well below 100) and eliminates most of the biodegradability benefit. In all other respects, phthalates behave similar to other diesters and are about 20 - 30% lower in cost. Phthalates are used extensively in air compressor lubricants (especially the reciprocating type) where low viscosity index is the norm and low cost clean operation is desirable.

Dimer acid is made by combining two oleic acids which creates a large branched dibasic acid from which interesting diesters are made. Dimerates exhibit high viscosity and high viscosity indices while retaining excellent low temperature flow. Compared to adipates, dimerates are higher in price (30 - 40%), have marginal biodegradability, and are not as clean in high temperature operations. Their lubricity is good and they are often used in synthetic gear oils and 2-cycle oils.

The alcohols used to make diesters will also affect the properties of the finished esters and thus are important factors in the design process. The alcohols may be reacted alone or blended with other alcohols to form coesters with their own unique properties. The first three alcohols in the table above all contain eight carbons, and when reacted with adipic acid, all create a dioctyl adipate. However, the properties are entirely different. The n-octyl adipate would have the highest viscosity and the highest viscosity index (about 50% higher then the 2-ethylhexyl adipate) but would exhibit a relatively high freeze point making their use in low temperature applications virtually impossible. By branching the octyl alcohol, the other two DOAs exhibit no freeze point tendencies and have pour points well below -60°C. The isooctyl adipate offers the best balance of properties combining a high viscosity index with a wide temperature range. The 2-ethylhexyl adipate has a VI about 45 units lower and a somewhat higher volatility. These examples demonstrate the importance of combining the right alcohols with the right acids when designing diester structures and allows the ester engineer a great deal of flexibility in his work.

Polyol esters

The term “polyol esters” is short for neopentyl polyol esters which are made by reacting monobasic acids with polyhedric alcohols having a neopentyl structure. The unique feature of the structure of polyol ester molecules is the fact that there are no hydrogens on the beta-carbon. Since this “beta-hydrogen” is the first site of thermal attack on diesters, eliminating this site substantially elevates the thermal stability of polyol esters and allows them to be used at much higher temperatures. In addition, polyol esters usually have more ester groups than the diesters and this added polarity further reduces volatility and enhances the lubricity characteristics while retaining all the other desirable properties inherent with diesters. This makes polyol esters ideally suited for the higher temperature applications where the performance of diesters and PAOs begin to fade.

Like diesters, many different acids and alcohols are available for manufacturing polyol esters and indeed an even greater number of permutations are possible due to the multiple ester linkages. Unlike diesters, polyol esters (POEs) are named after the alcohol instead of the acid and the acids are often represented by their carbon chain length. For example, a polyol ester made by reacting a mixture of nC8 and nC10 fatty acids with trimethylolpropane would be referred to as a “TMP” ester and represented as TMP C8C10.

Each of the alcohols shown above have no beta-hydrogens and differ primarily in the number of hydroxyl groups they contain for reaction with the fatty acids. The difference in ester properties as they relate to the alcohols are primarily those related to molecular weight such as viscosity, pour point, flash point, and volatility. The versatility in designing these fluids is primarily related to the selection and mix of the acids esterified onto the alcohols.

The normal or linear acids all contribute similar performance properties with the physicals being influenced by their carbon chain length or molecular weight. For example, lighter acids such as valeric may be desirable for reducing low temperature viscosity on the higher alcohols, or the same purpose can be achieved by esterifying longer acids onto the shorter alcohols. While the properties of the normal acids are mainly related to the chain length, there are some more subtle differences among them which can allow the formulator to vary such properties as thermal stability and lubricity.

Branched acids add a new dimension since the length, location, and number of branches all impact the performance of the final ester. For example, a branch incorporated near the acid group may help to hinder hydrolysis while multiple branches may be useful for building viscosity, improving low temperature flow, and enhancing thermal stability and cleanliness. The versatility of this family is best understood when one considers that multiple acids are usually co-esterified with the polyol alcohol allowing the ester engineer to control multiple properties in a single ester. Indeed single acids are rarely used in polyol esters because of the enchanced properties that can be obtained through co-esterification.

Polyol esters can extend the high temperature operating range of a lubricant by as much as 50 - 100°C due to their superior stability and low volatility. They are also renowned for their film strength and increased lubricity which is useful in reducing energy consumption in many applications. The only downside of polyol esters compared to diesters is their higher price tag, generally 20 - 70+% higher on a wholesale basis.

The major application for polyol esters is jet engine lubricants where they have been used exclusively for more than 40 years. In this application, the oil is expected to flow at -65°C, pump readily at -40°C, and withstand sump temperature over 200°C with drain intervals measured in years. Only polyol esters have been found to satisfy this demanding application and incorporating even small amounts of diesters or PAOs will cause the lubricant to fail vital specifications.

Polyol esters are also the ester of choice for blending with PAOs in passenger car motor oils. This change from lower cost diesters to polyols was driven primarily by the need for reduced fuel consumption and lower volatility in modern specifications. They are sometimes used in 2-cycle oils as well for the same reasons.

In industrial markets polyol esters are used extensively in synthetic refrigeration lubricants due to their miscibility with non-chlorine refrigerants. They are also widely used in very high temperature operations such as industrial oven chains, tenter frames, stationary turbine engines, high temperature grease, fire resistant transformer coolants, fire resistant hydraulic fluids, and textile lubricants.

In general, polyol esters represent the highest performance level available for high temperature applications at a reasonable price. Although they cost more than many other types of synthetics, the benefits often combine to make this chemistry the most cost effective in severe environment applications. The primary benefits include extended life, higher temperature operation, reduced maintenance and downtime, lower energy consumption, reduced smoke and disposal, and biodegradability.


Other esters

While diesters and polyol esters represent the most widely used ester families in synthetic lubrication, two other families are worth mentioning. These are monoesters and trimellitates.

Monoesters are made by reacting monohydric alcohols with monobasic fatty acids creating a molecule with a single ester linkage and linear or branched alkyl groups. These products are generally very low in viscosity (usually under 2 cSt at 100°C) and exhibit extremely low pour points and high VIs. The presence of the ester linkage imparts polarity which helps to offset the high volatility expected with such small molecules. Hence, when compared to a hydrocarbon of equal molecular weight, a monoester will have a significantly higher flash point giving it a broader temperature range in use. Monoesters are used primarily for extremely cold applications such as in Arctic hydraulic oils and deep sea drilling. They can also be used in formulating automotive aftermarket additives to improve cold starting.

Trimellitates are aromatic triesters which are similar to the phthalates described under diesters but with a third ester linkage. By taking on three alcohols, the trimellitates are significantly more viscous then the linear adipates or phthalates. Viscosities range from about 9 to 20 cSt at 100°C. Like phthalates, trimellitates have a low viscosity index and poor biodegradability with a price range between adipates and polyols. Trimellitates are generally used where high viscosity is needed as in gear lubricants, chain lubricants, and grease.

Summary

Esters are a broad and diverse family of synthetic lubricant basestocks which can be custom designed to meet specific physical and performance properties. The inherent polarity of esters improves their performance in lubrication by reducing volatility, increasing lubricity, providing cleaner operation, and making the products biodegradable. A wide range of available raw materials allow an ester designer the ability to optimize a product over a wide range of variables in order to maximize the performance and value to the client. They may be used alone in very high temperature applications for optimum performance or blended with PAOs or other synthetic basestocks where their complementary properties improve the balance of the finished lubricant. Esters have been used in synthetic lubricants for more than 60 years and continue to grow as the drive for efficiency make operating environments more severe. Because of the complexity involved in the designing, selecting, and blending of an ester basestock, the choice of the optimum ester should be left to a qualified ester engineer who can better balance the desired properties.

Base Oils & Lubricant Performance

By Anthony Garner

Introduction

The purpose of this thread is to open up productive conversation into the various kinds of base oils used in motor oil finished products. We will also look at how automotive lubricants are marketed as well as theory into lubricant heat control and friction reduction. This thread is not intended to be the final word, but rather an ongoing discussion where all are encouraged to contribute. Please provide links and or cited sources whenever possible.


Motor Oil Base Stocks

Base Stock: A motor oil base stock is usually refined from petroleum or a selected synthetic material. It is the main foundational component of the oil into which additives are blended to create a finished lubricant. Currently, the American Petroleum Institute (API) divides motor oil base stocks up into five separate group categories listed below.

Theory: Conventional Motor Oil

"Conventional lubricants are refined from crude oil. Refining is a process of physically separating light from heavy oil fractions. Crude oil is a natural substance. It contains millions of different kinds of molecules. Many are similar in weight but dissimilar in structure. Because refining separates products by weight, it groups molecules of similar weight and dissimilar structure, so refined lubricants contain a wide assortment of molecules.

However, not all of those molecules are beneficial to the lubrication process. Some of the molecules found in refined lubricants are detrimental to the lubricated system or to the lubricant itself. For example, paraffin, a common refined lubricant component, causes refined lubricants to thicken and flow poorly in cold temperatures. Some refined lubricant molecules also may contain sulfur, nitrogen, and oxygen, which act as contaminants and invite the formation of sludge and other by-products of lubricant breakdown." - Amsoil, Inc.

Theory: Synthetic Motor Oil

"Synthetic lubricants are not refined. They are chemically engineered from pure chemicals.

Pure – Because they are derived from pure chemicals. Synthetic lubricants contain no contaminants or molecules that “don’t pull their own weight.”

Uniform – Because synthetics contain only smooth lubricating molecules, they slip easily across one another. On the other hand, the potpourri of jagged, irregular and odd-shaped molecules of refined lubricants don’t slip quite so easily. The case with which lubricant molecules slip over one another affects the lube’s ability to reduce friction, which in turn, affects wear control, heat control and fuel efficiency.

Heat Control – Because uniformly smooth synthetic lubricant molecules slip easily over one another, they are superior friction-reducers to conventional lubricants. (Technically, because they slip more easily over one another, synthetics are said to have a lower “coefficient of friction” than conventional lubricants.) The less friction in a system, the less heat in it, too. Friction and heat are two major contributors to component failure and wear. By controlling friction and heat more effectively, synthetics significantly reduce the incidence of component failure and significantly reduce the rate of component wear." Amsoil, Inc.

The “Synthetic” Controversy

The topic of base oils and their perspective level of performance is generally a controversial topic among motor oil enthusiasts and on up through oil industry experts. Even defining what “synthetic” means results in controversy. Evidence of this can be seen by the conflicting comments made by oil industry experts after the much famed 1999 National Advertising Division (NAD) cases which defined the way synthetic lubricants would be labeled in the United States. In short, the result of the case ruled in favor of Castrol North America Inc. against the claim made by Mobil Oil Corp., that Castrol was not truthful in their advertising. The NAD ruling ultimately changed the way synthetic lubricants would be marketed in the United States setting the stage for what are known as group III lubricants to be labeled as synthetic. See the full two part article, A Defining Moment For Synthetics. Many would agree that the implication of the ruling blurs the lines of what a true synthetic lubricant really is and the levels of performance potential among the various base oil categories. In addition, some argue that this ultimately gives oil industry marketing the upper hand and leaves consumers at a disadvantage. A trip the local auto parts store reveals a dizzying array of synthetic motor oil choices. Terms like Full Synthetic, 100% Synthetic, Semi-Synthetic, Synthetic Blend and Synthetic Plus all grace the covers of motor oil bottles. Without further research, this often leaves one to wonder which version of synthetic motor oil best suites their specific application. Research into synthetic motor oils may also lead one to decide that top tier synthetic lubricants are not the best value for their dollar, while others may draw the conclusion that they will use nothing but top tier synthetics. The reality is that when considering such variables as driving habits, climate conditions, and equipment design, some motor oils fit some applications better than others, having their own proprietary blend of base oils and additives which make for a unique finished product.

For comparison, we will use three different motor oils as examples to help illustrate how motor oils are formulated using the various base stocks, how they are marketed, their associated cost, and discuss the perceived levels of performance each lubricant has.

Lubricant #1: Conventional Motor Oil

Chevron Supreme SAE 5W-30 API (SM)
Base stock – API Group II
Retail price per quart $2.99

Base Stock Origin: Refined from crude oil.

Today, conventional motor oils are formulated with Group II base stocks.

Other examples of Group II motor oils include but are not limited to Pennzoil (Yellow Bottle), Castrol GTX, Quaker State Peak Performance, Valvoline Conventional, Schaeffer Supreme 7000 Synthetic Plus, Brad Penn, and Shell Rotella T.

Note A: Advancements in oil technology like those pioneered by the Chevron Corporation have greatly improved the quality of conventional motor oils and have given way to group III synthetic motor oils. Read more on group II and III oil technologies at Chevron U.S.A Inc. and Shell Oil Company. Some have argued that this type of technology has closed the gap in performance between conventional motor oil and top tier synthetic lubricants.

Note B: Retail pricing provided by CSK Auto, Inc., and Amsoil, Inc., as of 10/18/09

Lubricant #2: Full Synthetic Motor Oil

Pennzoil Platinum SAE 5W-30
Base stock - API Group III
Retail price per quart $6.99

Base Stock Origin: Refined from crude oil.

Group III oils are refined from crude oil and are commonly marketed as “Full Synthetic” motor oil.

Other examples of Group III motor oils include Castrol Syntec, Amsoil Extended Life Synthetic Motor Oil, Schaeffer Supreme 9000 Full Synthetic, Shell Rotella T Synthetic, and Royal Purple High Performance Motor Oil.

Refer to notes A and B

Lubricant #3: 100% Synthetic Motor Oil

AMSOIL 100% Synthetic SAE 5W-30 Motor Oil
Base stock - API Group IV/V
Retail price per quart $8.75

Base Stock Origin: Pure chemicals derived from Crude Oil or Natural Gas.

Other examples of Group IV/V motor oils include Red Line, Royal Purple eXtreme Performance (XPR) Racing Oil, and Mobil 1.

Refer to note B.

100% Synthetic motor oils are often referred to as Top Tier Synthetics or Polyalpholefin (PAO) group IV based lubricants. Although PAO Group IV base stocks are not refined from crude oil like Group II and III oils are, there can still be some basis in crude oil. Ethylene is a colorless gas that is commonly derived from crude oil or natural gas. In addition to being a building block for Group IV synthetic base stocks, other products made from the ethylene family can also include plastics and rubber. Group V Ester oils are commonly used as additives in PAO based synthetic motor oils to improve various aspects of the finished product. See also Esters In Synthetic Lubricants. Finally, while many companies utilize PAOs in their finished products either as the main base stock or as an additive, there are only four companies currently in the United States that produce PAOs. According to the October 29, 2008 edition of Lube Report, producers of PAOs in the US include Chevron Phillips Chemical, ExxonMobil Chemical, Ineos Oligomers, and Chemtura. See also, Synthetic Lubricants.


Debate: Friction and Heat

Another area of debate among the oil industry experts is how the various base stocks perform with respect to coefficient of friction and heat reduction. For some, the conclusion has been made that with the advancements in base stock technology, there is little or no difference with respect to coefficient of friction and heat reduction between Group II/Group III and Group IV oils. However, this argument does not hold true for others. Some experts have indicated that PAO oils, or PAO oils blended with Ester oils both offer friction reducing abilities. Further, the purported added benefits of using a motor oil with friction reducing abilities include increased horsepower , higher rpm range, improved fuel economy, and lengthened engine component life. Provided below is responses from oil industry experts Tom Schaefer, formerly of the Hatco Corporation, and Ed Kellerman, manager of Oil Analyzers Inc., a subsidiary of Amsoil, Inc. Also provided is a related experience from an automotive Internet forum member.

Below, Ed Kellerman and Tom Schaefer comment about base oil characteristics with regards to Group IV Synthetic motor oils and friction reduction when compared to modern day Group II conventional motor oils.

"If we are talking just straight base stock, with no other additives, then group IV basestocks reduce friction far greater than groups II or III. You are correct: it’s a function of even molecular structure vs. molecules of all different shapes and sizes. The base stock argument, however, is for the most part irrelevant, in that there is so much more to a finished engine oil than just the base stock. It is possible to take a lesser base stock and improve anti-frictional characteristics by using high quality additives such as viscosity index improvers, anti-wear additives, friction modifiers, etc... Conversely, you can have a super high quality group IV base stock that if formulated with inferior additives and not formulated correctly, may not offer higher performance than a properly formulated group III finished engine oil. This is what makes the basestock argument irrelevant when it comes to the performance of a finished oil. AMSOIL engine oils are made from the finest base stocks and additives and there is no way any finished group II or III engine oil could come close." - Ed Kellerman

"A good group IV formulation will run cooler. This is not as important, however, as the fact that a group IV are far more resistant to thermal breakdown in high heat conditions, thereby offering far superior protection compared to groups II and III.

An oil's effect on engine temperature is a function of viscosity, coefficient of friction, and heat transfer properties. I don't doubt that these properties are similar among group I - IV hydrocarbons as they are all in the same chemical family, that is, there would be some differences based on such factors as aromatic content and molecular weight distribution, but the differences should be relatively small. Between different chemical families, however, the differences can be significant. Esters, for example, have significantly lower coefficients of friction and better heat transfer rates than most hydrocarbons, and much lower engine oil temperatures were frequently reported from the original all ester formulations back in the 1970s.

Since modern synthetic oils today are based almost entirely on hydrocarbon base oils, I wouldn't expect to see much difference in engine temperatures when viscosities are equal, especially since friction modifier additives are more potent than the base oils. That being said, those formulations with larger quantities of esters or ANs may indeed show some lowering of friction and temperatures." - Tom Schaefer

An automotive Internet forum member describes his experiences with lower engine operating temperatures when comparing conventional and synthetic motor oils.

"I work on an off-road race truck and we run oil temp gauges and found the following: During a fifteen minute race our oil temps would get up to 300+ if using any non synthetic oils. Mobil 1 dropped the oil temps by about twenty degrees to 280 and switching to Amsoil we dropped it to about 250-260 .......this is not representative of everyday usage but keep in mind that the water temp stays always in between 180-200 at all times no matter which oil.....so all in all it is kind of an accepted opinion that Mobil 1 is the cheapest and least effective of the synthetics but all of the higher end oils.......Amsoil, Royal Purple, etc. work better under extreme conditions. I guess it all depends on what your uses are. I just have my own opinions formed because of the info stated above." - LS1.com, Liquifire

Kellerman and Schaefer’s statements show slightly differing views with respect to the coefficient of friction of oil base stocks in their own right. However, both men seem to agree that a properly formulated lubricant with a quality additive package will provide improved anti-friction capabilities when compared to other lubricants using lower-grade additives. The exact rate to which friction reduction occurs between dissimilar finished lubricants is currently unknown. Further, a request was made for any relevant test data or studies on this subject, but none have been provided or located as of this writing. Mr. Kellerman did offer to review any information that would indicate no difference in friction reducing performance between GroupII/GroupIII and Group IV oils.

Further Discussion

While using cost effective Group II/III refined crude oil lubricants in mild-to-mid range performance applications can provide satisfactory results, other more demanding applications may gain additional benefits from utilizing Group IV based oils. Some example include, cooler engine operating temperatures, increased power and rpm ranges through friction reduction, lengthened oil change intervals, and better volatility and cold flow properties. Hopefully, after reading this post, one will come away with greater understanding and appreciation of what goes into producing a balanced lubricant, why some are cost effective, and why costly alternatives may offer a degree of increased performance potential.


For more information about AMSOIL synthetic lubricants and performance filtration products contact Anthony Garner at Competition Synthetics. Anthony is an Amsoil T-1 Certified Independent Dealer. E-mail Anthony at compsyn@live.com, or visit http://competitionsynthetics.com

What's In Your Motor Oil

By Tom Schaefer

To a formulator, a motor oil is a complex blend of 10-15 ingredients carefully balanced and tested to meet the industry specifications and market claims. To a blender it can be as simple as mixing three liquids together and filling it into bottles. And to the consumer it is, for the most part, a mysterious golden fluid with confusing numbers and letters that all make the same claims about being the best product possible for your car. In reality, it is all of these things.

While some oil producers blend many individual components to make their motor oils, most oils are made by simply blending three fluids; a DI package, a VI improver, and a base oil. These fluids, however, are the complex products of extensive research and technology. Following is a brief summary of each:

DI Package

An acronym for Detergent Inhibitor package, this thick dark fluid is a concentrated cocktail containing most of the performance additives needed to formulate an oil. DI packs are generally made by additive companies, the largest of which are Lubrizol (independent), Oronite (a Chevron Texaco company), and Infineum (ExxonMobil/Shell joint venture). These companies have extensive R&D facilities with numerous engine test stands for developing and qualifying motor oil formulations against various global standards. The development and testing costs are so high that they are beyond the reach of many oil blenders and marketers, so the work is usually left to these experts to concoct the formulation and give it to their customers. Naturally the approvals (SM, CF etc.) are only valid if one follows the formula, which requires that you use their DI pack in approved base oils. Some majors develop their own proprietary additive systems and buy the components instead of the complete package.

The DI pack for an SM/CF passenger car motor oil is jam packed full of goodies as follows:

Dispersants: These are chemicals that can disperse and suspend solid particles formed in the combustion of fuel that might otherwise be deposited in your engine as sludge. Consisting mainly of polyamine chemistry, these molecules have “polar heads” that attach to acidic molecules and solids such as soot, and a hydrocarbon tail that keeps it all in suspension until removed by the filter or oil change. Think of them as pollywogs who surround a particle – the fat heads bite the particle and the tails keeps them swimming. Dispersants are the largest component in the DI pack, especially in diesel formulations where there are a lot more soot particles to deal with.

Detergents: Also polar in nature, these “organometalic” products made from organic chemicals and metals are responsible for neutralizing acids formed during the combustion process, and cleaning the engine from high temperature deposits by removing and preventing the adherence of deposit precursors. Some detergents are “overbased”, that is, forced to contain more metal atoms than they really want to, and are best at neutralizing acid by-products. Others are “neutral” detergents which are somewhat more effective at the cleaning process. The most common metal atoms used are Calcium (Ca), Magnesium (Mg), and Sodium (Na), and these are all measurable in the UOA and VOA analysis. The organic portions are usually sulfonates, phenates, and salicylates.

Friction Modifiers: Often esters or partial esters, these additives are very polar, thus attaching to metal surfaces to improve lubricity. FMs are used to improve fuel economy, as opposed to reducing wear, and are additive to the effects of lower viscosity.

Seal Conditioners: Also often esters, seal conditioners are potent additives used in small dosages and designed to keep seals pliable. These are especially important for highly paraffinic base oils such as Group IIIs or PAOs due to the tendency of these base oils to shrink and harden seals.

Zinc Dialkyldithiophosphate: Affectionately known as “ZDDP”, this miracle multi-purpose chemical and has been the chief anti-wear (AW), extreme pressure (EP), and anti-oxidant (AO) additive for decades. It is so effective and low cost that it is virtually irreplaceable, which is why it survives all efforts to remove phosphorus (P) from oils to protect the catalyst. With modern oils putting caps on the maximum P allowed, other additives are now being used to supplement this old standard, such as Molybdenum anti-wear compounds and ashless anti-oxidants. There are different types of ZDDPs including primaries, secondaries, and aryls, each with its own strengths & weaknesses, and the mix is balanced to the type of service the oil will see.

Anti-Oxidants: These sacrificial molecules react preferentially with oxygen to protect the other components from the degrading effects of oxidation. While oxygen is 21% of the air we breath, most people don’t realize that in its pure form it is so reactive it is considered a flammable gas! Even diluted in air, it is everywhere and wants to react with just about everything if conditions are right, such as high temperatures. Oxidation, the reaction with oxygen, is the main cause of oil thickening and left unchecked will lead to varnish and carbon deposits as well. With the ZDDP being reduced, supplemental AOs are more critical in modern oils and usually more than one kind is used to capitalize on the common synergistic properties they possess. The most common types are phenolics and amines.

Rust & Corrosion Inhibitors: These additives are smaller in dosage and are designed to protect iron alloys and yellow metals from corrosion induced by oxygen, acids and water. They work by attaching to metal surfaces and therefore compete with some other additives and base oils, so balance is critical.

Pour Point Depressants: These polymeric molecules interfere with the formation and growth of wax crystals from residual paraffins. They are generally not needed in full PAO and ester based oils since they contain no wax.

Anti-Foams: Often silicone products, these molecules are not soluble and work by suspending tiny micron sized droplets that prevent foam from forming or help the foam break faster.

Diluent Oil: Also called carrier oil, this component is usually mineral oil and is present at about 5-20% in the DI pack to solubilize all the additives and adjust the package to a consistent and manageable viscosity for pumping and blending.

Finished DI packages will vary in chemistry, balance, and dosage according to what kind of oil you are making. For example heavy duty diesel DIs will have more dispersants and be used at dosages up to about 15% of the finished oil. Passenger car/light truck DIs have less ZDDP and more anti-oxidants and are generally dosed at about 8-12%.

Viscosity Index Improvers

Abbreviated VIIs, these are huge polymeric molecules, often with molecular weights in the millions. Their purpose is to improve the viscosity index of the finished oil so that multi-grades can be made.

All organic liquids will thin out when heated and thicken up when cooled, but they don't all do so at the same rate. Viscosity Index is simply a scale to compare the rate of viscosity change with temperature among different fluids. A fluid that thins more upon heating (and therefore thickens more upon cooling) has a lower VI than one that thins less and thickens less. Or put another way, higher VI oils change their viscosity less when the temperature changes. This can be a good property for lubricants that are used in a wide temperature range.

The VI scale was originally established by assigning a value of "0" (zero) to the worse known base oil at the time, and "100" to the best. The theory was that all other base oils would then fall between these end points. Apparently they didn't anticipate synthetics or hydrocracked mineral oils back then.

The way VI Improvers work is that the huge molecules tend to coil up into balls when cold, thus having little effect on the oil’s flow (viscosity). When hot, however, the molecules uncoil and stretch out, thus interfering with the flow of the oil and causing an increase in viscosity (actually a reduction in thinning, but let’s not get technical). If you put these molecules into a light 5W base oil, the low temperature viscosity is little affected, i.e. remains a 5W, but the high temperature viscosity rises, giving for example a 5W-30 multi-grade. By reducing the thinning effect of heat, the Viscosity Index of the finished oil is increased.

VI Improvers are available an various chemistries and forms. Some are solids that need to be dissolved in the oil, but most are pre-dissolved in a carrier oil to give a thick, honey-like liquid that is easier to handle and faster to blend. Dosages are usually under 10% and vary with the VII chemistry, target oil grade, and base oil type.

People tend to think that the less VI Improver the better, but that depends on the type of VI Improver used. Some are much more shear stable than others, and a higher quantity of a shear stable VII may be better than a lower quantity of a non-shear stable VII. In addition to permanent viscosity loss cause by breaking (shearing) the large VII molecules, they also exhibit temporary viscosity losses under high shear, and this lowers the HTHS viscosity and improves fuel economy.

Base Oils

Constituting 80-90% of the finished motor oil, the base oil(s) play a very important role. The structure and stability of the base oils dictate the flow characteristics of the oil and the temperature range in which it can operate, as well as many other vital properties such as volatility, lubricity, and cleanliness. The two major categories of base oils are Mineral Oils and Synthetics.

Mineral oils begin with crude oil, a mixture of literally hundreds of different molecules derived from the decomposition of prehistoric plant and animal life. The lighter more volatile components of crude oil are stripped away to make gasoline and other fuels, and the heaviest components are used in asphalt and tar. It’s the middle cuts that have the right thickness or viscosity for lubricants, but first they must be cleaned up; undesirable components such as waxes, unsaturated hydrocarbons, and nitrogen and sulfur compounds must be removed. Modern processing techniques do a pretty good job of removing these undesirable components, good enough for well over 90% of the world’s lubricant applications, but they cannot remove all of the bad actors. And it’s these residual “weak links” that limit the capabilities of mineral oils, usually by triggering breakdown reactions at high temperatures or freezing up when cold. These inherent weaknesses limit the temperature range in which mineral oils can be used and shorten the useful life of the finished lubricant.

Mineral oils are further subdivided into three subgroups (Group I, Group II, Group III) that differ by the degree of processing they undergo. Higher groups have been subjected to hydrotreating or cracking to open aromatic (ringed) molecules, eliminate unstable double bonds, and remove other undesirables. This extra treating yields water-white clear liquid with higher VIs, enhanced oxidative stability, and lower volatility.

Group IIIs are a somewhat controversial class as they are derived from crude oil like Groups I & II, but their molecules have been so changed by severe processing that they are marketed as Synthetics. Most people now accept Group IIIs as synthetic, but the discussion remains heated among purists, and I’m going to duck by not taking a side here.

Synthetic base oils are manufactured by man from relatively pure and simple chemical building blocks, which are then reacted together or synthesized into new, larger molecules. The resulting synthetic basestock consists only of the preselected molecules and has no undesirable weak links that inhibit performance. This ability to preselect or design specific ideal molecules tailored for a given job, and then create those molecules and only those molecules, opens a whole new world for making superior basestocks for lubricants. In fact, the entire formulation approach is different: instead of trying to clean up a naturally occurring chemical soup to acceptable levels with a constant eye on cost, the synthetic chemist is able to focus on optimum performance in a specific application with the knowledge that he can build the necessary molecules to achieve it. And since full synthetic oils are generally a company’s premier offering, their best foot forward so to speak, the additives are often better and in higher doses as performance trumps cost.

In general, synthetic base oils offer higher oxidative and thermal stability, lower pour points, lower volatility, higher VI, higher flash points, higher lubricity, better fuel economy, and better engine cleanliness. The amount and balance of these improvements vary by synthetic type, and can be quite significant for the engine and user.

There are many types of synthetic base oils, the most common being Polyalphaolefins (PAOs), Esters, Alkylated Naphthenes (ANs), and more recently Group IIIs. These different types of synthetic base oils are often blended together (or even with mineral oils), to give the balance of properties desired. All offer improved performance, but at a higher price, which brings up the question of value - how much performance to you need, and how much should you pay for it?

For the average car owner, driving conditions are mild enough for conventional mineral oils to work satisfactorily, provided they are changed relatively frequently (3,000-5,000 miles). For those users with high performance engines, severe climates, hard driving, or utilizing long drain intervals, synthetics can offer good value and may even be required. And then there are those who so love their cars that nothing but the very best will do for their baby.

So, as you can see, modern motor oils are very simple mixtures of very complex ingredients. Choosing the right components of the right chemistry in the right dosages is a real balancing act, as each of the components have their own pluses and minuses and can interact or compete with each other. Don’t try this at home - leave it to companies you trust who have the technology, R&D, and resources to achieve the necessary balance so critical to performance.Choosing the right components of the right chemistry in the right dosages is a real balancing act, as each of the components have their own pluses and minuses and can interact or compete with each other. Don’t try this at home - leave it to companies you trust who have the technology, R&D, and resources to achieve the necessary balance so critical to performance.

Works Cited: Bob Is The Oil Guy.com, Article of the Month – February 2009

Amsoil: A Historical Account

As a result of studying various aspects of the lubricants industry, I came into contact with Tom Schaefer, former vice president of sales and marketing for the Hatco Corporation. Schaefer, now retired, periodically contributes helpful tidbits of information with respect to the motor oil industry.

In securing correspondence with Mr. Schaefer, I didn’t hesitate to ask him a few questions about Amsoil. I had recalled that Al Amatuzio utilized the Hatco Corporation to some degree in sixties for the development of Amsoil’s first synthetic motor oil. Compiled below is Mr. Schaefer’s recollection in regards to the Hatco/Amsoil historical account he personally witnessed.

"I joined Hatco in 1969, so I was there (in the lab at the time) when the Hatco/Amsoil relation began. Al Amatuzio was the driving force behind the motor oil development as it was his concept and he was developing the marketing structure to sell it. The formulating was done by Hatco and an additive company, and Hatco did the ester manufacturing and oil blending while Amsoil arranged the packaging & distribution, so it was a joint effort. I don't recall there were any formal R&D agreements, just a close working relationship, and the oils developed for Al were to his specifications and sold exclusively to Amsoil.

While others were selling synthetic motor oils before Amsoil, none were API certified oils and many failed. Amsoil was definitely the first company to market an API certified oil - 10W-40 SE/CC based on a diester. Yes the oil was formulated and manufactured by Hatco, but the concept, requirements, and marketing came from Al Amatuzio. Hatco had the technology but no means to market, while Al had the marketing capability but lacked the technology and manufacturing capability. It was a joint effort and neither could have succeeded without the other.

There was no API certification program back then, but yes the oil was fully tested in all of the API engine sequence tests and passed all of the SAE specifications for SE/CC. In addition, it was reviewed by a military review board and approved under MIL-L-46152. It was the real deal.

For the ancient history buffs, the oil was called Hatcol 2250 and contained Ditridecyl Adipate (diester), an Oronite DI package, a Rohm & Haas dispersant PMA type VII, and a supplemental anti-oxidant. It ran from 1972 to about 1976, at which point Hatco developed an improved version that later passed SF/CC.

Hatco and Amsoil departed company in the late 70s as Amsoil's volume grew to a point where it made sense for them to develop and blend their own products. I retired last year (2007) so I do not know what relationship they may have today." - Tom Schaefer

As an Amsoil Independent Dealer, having the distinct opportunity to converse with Mr. Schaefer and discover the actual historical facts about the early years of Amsoil, Inc. was a shear delight. Getting this data straight from such a credible source is greatly appreciated. Special thanks to to Tom Schaefer for his willingness to shed new light on this topic.

Tom Schaefer can be contacted at the Internet forum, http://www.bobistheoilguy.com under user name Tom NJ



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