Oil Chronicles: Synthetic oils
Do they out-perform conventional oils?
The oil in your engine has an incredibly difficult job. It's lying cold in the bottom of the pan when the engine starts, then has to flow almost instantaneously all the way to the valve gear at the very top, and everywhere in-between to protect bearings, pistons, cylinder walls and everything else that moves or touches something that does. And it must reliably continue to protect these parts no matter how hot it gets, how fast the engine runs or how hard it works.
It must perform this job over a period of months or years, enduring thousands of miles of short trips and commutes that never quite get it up to temperature, day-long freeway drones and (for some) occasional race-track or twisty mountain two-lane flogs through the bitter cold of northern winters and the sticky hot of southern summers. And it must retain its protective properties while continuously fighting rust, contaminants and passage-clogging deposits.
To be able to do this job reliably, engine oil has evolved from a relatively simple slippery substance refined from raw crude oil to a brilliantly engineered, meticulously developed blend of refined petroleum and highly-sophisticated additives that enable it to retain its critically important protective properties through all those months and miles and inhospitable conditions. But not all engine oils are the same.
A wide variety of basic oils is available, some good enough for light usage for a reasonable period of time, some mid-line conventional oils that are better for long-term use and, finally, higher-performing, longer-lasting, more-expensive oils that are best for much tougher duty. And today most of the highest-performing oils are "synthetics."
Synthetic oils are typically engineered and manufactured from chemically modified petroleum components instead of whole crude oil, although they can be made from other materials as well. And while they are more expensive than conventional oils, synthetics do provide generally superior chemical and mechanical properties, especially in extreme temperatures.
"We are moving into more of a synthetic realm because it's better-engineered oil," said Jeff Hsu, technology director for Quaker State. "Our synthetic oils still come from hydrocarbon crude sources, but they are very highly refined. They go through more processes during refining to take out contaminants such as sulfur, aromatics and low saturates that would cause them to age, oxidize or degrade quicker. The high point of a good synthetic is how the additive package takes advantage of a good base oil to make it a higher-performance oil."
Do synthetics both perform better and last longer?
"A synthetic oil has more natural VI (viscosity index) for better properties in low and high temperatures," Hsu said. "It provides better start-up and faster flow at low temperatures, down to -40 F, and allows very extreme high temperatures without oxidizing, thickening and turning black. A synthetic oil that is more pure with more natural VI will stay true to the viscosity longer and reduce oxidation quite a bit."
Hsu added that automakers are increasingly using thinner, ultra-low-viscosity synthetic oils to improve fuel efficiency. Not only is the wear-protection better, such oils also enable better fuel economy. This is evident in Quaker State's full synthetic offering, Ultimate Durability, which, Hsu said, provides unsurpassed protection against friction-related wear.
"Only synthetic oils are capable of being formulated to much lower viscosity," he said, "and with that trend toward thinner and thinner oils, you have to be able to keep the bearings protected. Also, because a good synthetic oil is cleaner and more robust, it gives you a little more assurance if you have to go longer between oil changes."
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