Beat the Heat

Preparing a car for any type of motorsports competition is an exacting exercise. The difference between winning and just running in an event can often be measured in the thousandths of a second, so competitors need to eke every last ounce of performance from their vehicles. That’s why even minor ingredients in the performance equation—like different engine lubricants—can be extremely important. An engine that runs too hot will wear more quickly, produce less power, and be more prone to failure. The right lubricant can help keep it cool.

The modern automobile engine has made great developmental strides in the last couple of decades; this has placed new demands on engine lubricants. The oil industry’s response has been to develop a new generation of high-quality, high-tech oils based on synthetic base molecules. These new oils last longer, develop more engine power, and are significantly more durable than standard petroleum oils. Many people seem to think that the claims made by these new “wonder oils” are too good to believe, however; this has cast a shadow over the reputation of synthetic oil. Even among motorsports enthusiasts, there is great confusion as to what synthetic oils are, how they are made, and just how they compare to petroleum oils.

In order to learn more about synthetic oils, we traveled to the production facilities of the most respected synthetic oil manufacturers: Red Line Synthetic Oil Corp,, Valvoline, and Bel-Ray Total Performance Lubricants.

Red Line has been in business for quite some time now; and the company’s synthetic oils, lubricants, and additives are used by more national racing champions than any other. In fact, at the 1989 SCCA Valvoline Runoffs, more than half of the winning drivers were using Red Line products.

Valvoline is also no stranger to the winner’s circle; this company’s products have helped to place drivers like Al Unser, Jr., Bobby Rahal, Mark Martin, and Dorsey Schroeder at the top of their fields. Now, after ten years of intensive development, Valvoline is releasing its own line of synthetic motor oils, gear oils and greases.

Bel-Ray has been producing specialty lubricants for more than 40 years. This manufacturer has provided lubricants for NASA’s moonwalker, nuclear submarines, tanks, aircraft carrier catapults, and mining equipment weighing 40,000,000 (as in million) pounds. Bel-Ray lubricants are also used heavily in the motorcycle and automotive racing arenas.

Synthetic Oil Construction

Synthetic oils can be derived from several sources, but the most stable are derived from polyol ester bases. These bases are laboratory creations; to make them chemists break apart the molecules that make up a variety substances, like vegetable and animal oils, and then recombine the individual atoms that make up those molecules to make new, synthetic molecules. This process allows the chemists to actually “fine tune” the molecules as they build them. As a result, synthetic molecules are often much more stable—less prone to break apart—than the original molecules. For instance, the molecules of most synthetic oil bases contain no reactive carbon atoms; this is because reactive carbon has a tendency to combine with other elements—like oxygen, to make acids—which makes them unstable, especially at high temperatures. So, in a sense, synthetic oil bases are made up of purpose-built molecules; and like purpose-built race cars, they tend to be streamlined, with no unneeded ingredients or added bulk.

Once the synthetic polyol ester bases are created, anti-wear additives are added. The most common of these are the zinc dithiophosphates, which are essentially combinations of zinc, phosphorus, and sulfur molecules. These combinations are extremely effective as anti-oxidant, anti-wear, anti-corrosion inhibitors. They have good thermal stability, but must be blended in such a way that the ingredients react at the proper temperature.

After that, other additives are added to control rust and foaming, contain foreign particles, etc., until the oil meets the requirements of its intended application.

Each oil manufacturer takes a slightly different approach to producing their synthetic lubricants, but all are guided by the three basic functions of engine lubricants: Friction reduction, heat removal, and containment of contaminants. Let’s take a look at how engine oils provide these functions.

Friction Reduction

Friction reduction can be define as the action of maintaining a lubricant between two surfaces that are moving with respect to one another, which avoids a collision of the two surfaces and the resultant damage. The better the lubricant is, the better its friction reduction abilities. Since friction produces heat as well as wear and tear, a good lubricant will reduce overall heat buildup in the engine. This item is especially important, because friction produces a significant portion of the heat generated in the process of operating an engine. Lower operating temperatures will also benefit the lubricant, enabling it to remain more stable and less prone to oxidation. (More on this later in the story.)

Any discussion of a lubricant’s friction-reducing properties must also examine its ability to provide Hydrodynamic Lubrication. This condition is present when two interacting metal surfaces are successfully kept apart by a lubricating layer, which eliminates the friction between the surfaces. This can be done mechanically: In the combination of a cylindrical journal and bearing, the rotary shaft acts as a pump which maintains the film of lubricant. The journal floats on a thin film of oil of an equilibrium thickness between the oil input and oil leakage, mostly at the bearing ends. In a situation like this, any friction present is caused by the molecular friction occurring within the lubricant—i.e., its viscosity.

Viscosity can be defined as a fluid’s resistance to flowing freely as a result of its internal molecular construction. Viscosity is perhaps the most important property of a lubricant. It controls the formation of lubricating films under both thick and thin film conditions. It affects heat buildup, governs the sealing effect of oils and oil consumption, and significantly affects engine startup at extreme temperatures.

Multi-grade ratings of petroleum oils are made by adding polymeric plastic thickeners to an oil with a very light viscosity. An example of this is 10W-40 oil, which is created by thickening a 10W oil to the equivalent of an SAE 40W oil at 212 degrees F. The reason a 10W oil is used is to maintain low viscosity at low temperatures; this helps with engine startup and cold weather performance. The thickeners increase viscosity at higher temperatures. Unfortunately, when the large molecules of the polymer thickeners encounter a high-stress area, like a bearing, these big molecules tend to align themselves to create a path of least resistance. This greatly reduces the film strength of the oil; the result can be an apparent viscosity that is much lower than the viscosity listed on the container. In fact, a standard 10W-40 oil, when subjected to high stress, may perform to SAE 20 specifications, simply because the added thickeners cannot cope with the additional stress.

Synthetic oils require no thickeners to achieve multi-grade ratings because they are constructed from naturally multi-graded basestocks. In addition, the actual shape of synthetic oil base molecules enables those synthetis to maintain a much higher viscosity under stress. Because of this, most synthetics provide significantly greater viscosity than petroleum oils under high speed conditions.

It is even more important that an oil provide a seal between the piston rings and cylinder walls to ensure maximum compression on the stroke. Most petroleum oils will allow blow-by because their weaker viscosity allows high-pressure gasses to escape into the crankcase area. Modern synthetic oils, on the other hand, prevent blow-by due to better viscosity.

For example, Red Line claims that its 10W-30 Racing Oil will not only outperform 20W-50 petroleum oils, its less dense molecular structure also makes for significantly less viscosity friction within the engine. Bel-Ray has developed a 5/60 weight oil to handle the extreme demands of high-revving motorcycle engines, while Valvoline has concentrated more on automobiles with its 10/30 and 20/50 offerings. In each case, the superior structure of synthetics means better protection. This also help in cold-start situations, where oil circulation is critical.

Heat Removal

While most the engine's hear is absorbed by the cooling system, about ten to twenty percent of engine heat is absorbed by the oil. Furthermore, engine oil is the principal coolant for the pistons, main bearings, rod bearings and camshaft. The oil must be able to absorb the heat, store it, and release it without ever compromising its own stability. The rate at which this absorption, storage and release occur is known as the heat transfer coefficient. The faster the rate, the better the oil.

Oils also have a heat capacity, which is the amount of heat the oil can absorb before a change in the overall oil temperature occurs. Much of this has to do with the polarity of the oil. Polarity is a characteristic of the individual molecules that make up an element; it helps determine the stability of those molecules, and therefore that element. Synthetic oils are more stable than conventional petroleum oils under high temperatures; this enables synthetics to out-perform their petroleum counterparts by approximately 10 percent in the area of heat transfer. Furthermore, it means synthetics will absorb 5-10 percent more heat before a change in oil temperature occurs.

Petroleum oils are not only less efficient at removing heat, they also begin to break down significantly above 275 degrees F. Unfortunately, temperatures at high stress areas within the engine--like cam and follower contact areas, pistons, etc.--can routinely exceed 400 degrees F. Petroleum oils may boil away, or vaporize, a those temperatures, leaving high stress areas without adequate protection.

In addition, conventional petroleum oils react with oxygen at high temperatures to form acids, which then combine to form varnish deposits that coat the metal. The varnish deposits formed by this process, which is called oxidation, will reduce the ability to transfer heat, and will build up to cause sludge and ring sticking.

Remember, synthetic bases are more stable partly because they are formulated without reactive carbons, which have a tendency to react with oxygen. The more stable molecular structure of modern synthetic oils enables these products to resist this harmful oxidation, as well as vaporization. Red Line's synthetic motor oil, for example, will still lubricate at temperatures in excess of 700° F. This resistance to breakdown means a cleaner oil, and a more durable one.

Containment of Contaminants

Another important function of oils is to contain and retain contaminants within the engine. Engine combustion can leave behind byproducts, like partially burned gasoline, water, dirt, etc.; it is the oil's job to contain these contaminants and prevent them from doing harm to the engine. Oils contain these particles through the use of additives called dispersants. These chemicals encircle foreign particles and prevent them from coagulating with others; this lessens their effect by helping to prevent clumping, plating and varnishing.

Most synthetic oils are formulated to contain significantly more dispersants than conventional petroleum oils; this means that synthetics can be used for much longer drain intervals. Their greater dispersancy also makes synthetics a better choice for engines that are driven only a few miles at a time. Unburned fuel is more likely to build up into sludge and varnish in engines that do not regularly reach operating temperatures. If this fuel is not vaporized by heat, the oil needs to be able to contain and isolate the fuel particles before they get a chance to build up.

The combination of better stability and dispersancy enables synthetic oils to maintain much longer oil change intervals than conventional petroleum oils. For example, Bel-Ray says its EXS synthetic can remain in service for upwards of 15,000 to 20,000 miles of non-racing use, provided an oil analysis program is in effect to monitor critical engine functions.

Another factor that makes synthetic oils long-drain lubricants is their better oxidation stability. As mentioned, synthetics do not break down as much at high temperatures as their conventional petroleum-based counterparts; this means synthetics produce less varnish and sludge, which shorten the life of an oil.

Conclusion

Whether you're building a high-performance engine for your race car, or are driving the latest in high-tech hardware, chances are good that performance and reliability will be greatly enhanced by the latest synthetic lubricants. Synthetics have been proven to increase horsepower, lower engine operating temperatures, increase gas mileage, and dramatically extend the life of your engine. Translated, that means more trips to the winner's circle, as well as more satisfaction down the road.

The Price Tag

Synthetics versus petroluems: A realistic cost-benefit analysis of synthetic oils

When it comes to technology, there's always a price to pay. If you want the biggest, the fastest, or the best, you can bank on the fact that it's going to cost you more. Just as there are folks who are happy with a 10-inch black and white TV instead of a gargantuan wide-screen sensory assault weapon, however, some car owners look at the added cost of running synthetic oils and question just how much better these products will perform. After all, automobiles have been running with various combinations of dinosaur bodies for decades with little trouble, so why switch?

Well, let's first look at the basic cost of synthetic oil versus petroleum-based oil. A bottle of Red Line Synthetic Oil costs about $7.25 a quart, while the average petroleum oil clicks the register at about $1.50 per quart. This means the average five-quart engine would ring up a purchase of about $36.25 versus $7.50. At face value, it would appear that synthetics demand a much higher investment; but let's probe deeper.

First drainage intervals are usually doubled, sometimes tripled, with the use of synthetic oils. This means that for every $36.25 spent on synthetics, $15.00 to $22.50 worth of petroleum oils must be purchased to attain comparable mileage figures.

Next, take into account the performance properties of synthetics. Their superior protective abilities can greatly increase the life expectancy of a street-driven engine. On the race track, this can mean fewer rebuilds within a given racing season--plus more horsepower. In addition, synthetics have demonstrated their abilities to reduce the amount of damage, should a catastrophic engine failure occur.

In layman's terms, this could mean the difference between driving the family truckster 200,000 miles without failure, or giving it up to terminal engine failure at 125,000 miles. It could also mean an engine that holds together for that last lap (or run) to give you the win. Bottom line: fewer rebuilds mean you spend a whole heck of a lot less money down the road.

If it seems as if we're pushing for synthetics, it's because we are convinced the long-term benefits more than overwhelm the higher initial cost. In fact considering how much synthetics do for the money, they're a downright bargain. So, as that transmission commercial suggests, you can pay 'em now, or you can pay 'em later. We'll take our ounce of prevention now, thank you--preferably in something polyol-ester, and neatly packaged in a one-quart bottle.

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Comments
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Teh E36 M3
Teh E36 M3 SuperDork
5/29/09 2:56 p.m.

Another interesting point I've seen made is the question of: How much do you spend on gas for your car? And it lasts how many miles? Essentially for the cost of one tank of gas you get the better protection of synthetic oils. The $20 difference in my opinion is not worth saving.

Also- it would be interesting to have a story on building and breaking in a new engine- would you use synthetics? Is there a particular way to build an engine wherein synthetics would be useful as a first fill? How do the OEM's (Chevy, Porsche, BMW) ship their engines with synthetic new from factory? How long does it take to break in an engine? Does the "motoman" break it in like you drive it theory hold water?

Good story regardless.

Guam135i
Guam135i New Reader
6/20/11 1:55 a.m.

Is this also true for the older car where the machinning tolerances are farther off? Like for example my 1970 Mini which the engine oil also serves as the transmission oil, can I use a synthetic oil?

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