Photo by Scott Singleton, Royal Purple Raceway
The Truth About Motor Oil
There are misconceptions concerning motor oils available in the consumer marketplace. Similar myths are just as prevalent in motorsports, including drag racing. Royal Purple offers its expertise to clarify some of the most common drag racing oil myths.
Myth #1-Thicker oil is better.
In decades past, motor oil additive technology did not provide the performance and protection available in modern premium motor oils. Racers and engine builders had to rely on heavy viscosity to provide an oil film adequate for high-horsepower engines. This is no longer the case with today’s premium performance motor oils and advanced additive technology these premium oils employ. For performance, the lightest viscosity motor oil offering adequate protection is the best choice. Using a motor oil of heavier viscosity than needed will require more horsepower to circulate, cause excessive oil pressure and likely increase engine operating temperature.
Myth #2-Higher oil pressures are better.
Similar to Myth #1, the “more is better” argument does not hold for oil pressure either. Oil pressure is not an indication of protection; it is merely a direct measurement of restriction to fluid flow. The more difficult it is for motor oil to flow through an engine’s oil circuit, the higher the oil pressure. A popular rule of thumb is 10 pounds of oil pressure per 1,000 rpm. This will work fine in most applications but is not necessary, especially for higher revving engines. “The truth is that it takes horsepower to run that much oil pressure,” says Herb Kutz, former NHRA record holder and western regional sales manager for Royal Purple. “Less pressure equals more horsepower and quicker E.T.s. Each engine is different, and you should check with your engine builder for specifics; however, most drag race motors under 600-hp should be able to do just fine with 50-55 pounds.”
What is actually more important is oil flow. Typically, oil pressure doesn’t directly support anything in the engine, but a reliable, robust oil supply will provide proper lubrication, protection and cooling.
Myth #3-Synthetic oils will not work in drag racing.
Today’s modern engines are built with closer, exacting tolerances and demand a high-quality, high film strength oil to survive the heat and extreme rpms they face with each pass down the track. “Synthetic lubricants will last longer, protect better and deliver more horsepower through less friction and drag. While it makes no sense practically, it is truly amazing to see how many racers with $20K motors use good old $4 mineral oil because it’s cheaper,” Kutz continues.
Myth #4-Synthetic oils are thinner than mineral oils.
The SAE viscosity grade (e.g., 10W-30, 20W-50) listed for particular oil represents a range of measured viscosity, and the viscosity measurements are performed at particular oil temperatures (between 100° and 212°F). The temperature range is intended to approximate engine “operating temperature.” Outside of this temperature range, the measured viscosity of motor oils can vary greatly, even when comparing oils of the same SAE viscosity grade. Oils with greater viscosity stability will thicken less at cooler oil temperatures and thin less at higher temperatures. High quality synthetic oils will typically exhibit more consistent viscosity across all temperatures. This, along with the more slippery feel common of quality synthetic engine oils, perpetuates the myth that synthetic engine oils are thinner than non-synthetic engine oils.
Myth #5-All synthetic oils are the same.
Just as all racers or all engines are not the same, neither are synthetic oils. Not all synthetic motor oils are created equally. What’s the easiest way to figure out the difference? Ask the engine builders and racers who are winning what they use and why. “The [Royal Purple] oil is the best there is on the market,” notes Mike Edwards, 2009 NHRA Pro Stock Racing champion. “Royal Purple is a mainstay in our race car. I wish I could keep it a secret, but when it is this good, it is hard to keep under wraps.”
About Royal Purple
Royal Purple produces a broad line of high-performance lubricants for automotive, consumer and industrial applications. For more information about Royal Purple or its products, contact Royal Purple, Inc., One Royal Purple Lane, Porter, TX 77365, 281.354.8600, Royalpurple.com.