What's the difference between synthetic and conventional oil?

 

The oil we put in our engines serves multiple purposes. It coats the metal parts and allows them to run on a thin, smooth layer of lubrication, thus reducing friction and wear. It works as an additional coolant, holds by-product carbon particles in suspension until the oil filter traps them, neutralizes acids, and employs solvents to keep the engine clean. That’s a serious resumé and if there’s one thing motor enthusiasts love to do it’s debate the merits of one oil over another. Sooner or later somebody brings up the “synthetic vs regular oil” issue and the conversation is literally off to the races with “experts” pressing advantages and disadvantages with knowing passion. Like most arguments, there are degrees of “rightness” and “wrongness” depending on what you’re driving and how you’re driving it. The oil you use in your family car (even if you have tuned it up to breath a little life into that run to the grocery store) isn’t going to be the same oil that goes into a racing engine. Without trying to put an end to a discussion that has no end, let’s look at a few facts.

O bviously “regular” oils are mineral-based products refined from crude oil taken from the ground. Over the past 20 years these lubricants have been “refined” even further, particularly in the area of viscosity enhancers -- meaning modern oils flow better over a range of temperatures. This, in combination with engines that sport tighter clearances and better machining, allow for the use of thin oils that both reduce friction and improve fuel efficiency. In the world of racing, for instance, very few teams are going to be using motor oil with single rated viscosity. (The exception would be some nitro-burners.) Racers not only want efficient operation and greater power, they want the best lubrication of engine parts as quickly as possible. (Start-ups deliver high engine wear, so you want an oil that gets to work quickly.)

Synthetic oils, which have been around since the 1970s, have the same natural ingredients as “oil oil,” but they are distilled in a chemical plant where the concept of refining goes techno-geek. Try getting your head wrapped around the concept of “synthesized-hydrocarbon molecular chains” and base fluids including “ polyalphaolefin, synthetic esters, and alkylated aromatics.” Practically, what the heck does this mean?

Synthetic oils:

• are all season and have multi-viscosity properties, some flowing as much as seven times faster than regular oil.
• can stand extremes of engine temperature (some above 400°F) more efficiently.
• can boost effective horsepower more effectively than thinner regular oils.
• can be used for as much as 10,000 miles before requiring an oil change.
• contain fewer contaminants like sulfur, wax, and other elements that contribute to sludge build-up.

Of course, these synthetic oils are more expensive and there are some things they don’t do, including:

• eliminate the need for oil changes.
• eliminate engine wear.
• or improve miles per gallon received.

The major advantage of synthetics is superior lubrication that significantly reduces engine wear over the long term.

For regular drivers and performance car enthusiasts, proponents suggest there’s a place for both types of oil. Conventional wisdom now suggests that you want to use “regular” oil while breaking in an engine. At this phase of an engine’s life, you want some wear to make sure all the components get properly smoothed down. (On the other hand, there are plenty of performance cars that come from the factory using synthetic oil.) Depending on who you ask, this breaking-in period can be as short as 500 or as long as 5,000 miles. At whatever point you choose, however, the switch from regular to synthetic oil is intended to then slow engine wear down as much as possible. (And you don’t want to mix regular and synthetic as that’s a great recipe for sludge.) At the racing level, of course, a team is going to test various oils, determine what horsepower gain is returned, gauge the viscosity and temperature tolerances -- in short, make a science out of oil choice versus engine benefit.

The best answer to this debate may be that there are virtues to both types of oil. Anything you put in your engine from the new car dealer or any modification you make to your vehicle, whether it's a racer or the family car, has to be looked at in terms of the goal you're seeking to achieve. Without question, the chemical composition of synthetic oils have a quality and uniformity at the molecular level that just isn't found in traditional, "regular" oils. Synthetic oils will continue to be fine-tuned in the laboratory to give even higher levels of performance and benefit. As we ask more of our engines, not only in terms of output but in the areas of clean and efficient operation, no one can afford to rule out synthetic oils as a viable option, on or off the track. Like everything about automobiles, lubrication techniques are evolving rapidly and the days of indiscriminately telling the guy at the gas station to "just add a quart" are definitely over.

 

Courtesy of topspeedracer.com