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The history of graded gasoline dates back to the 1920s. Today, when a consumer pulls up to a typical gas pump, they have three grades of fuel from which to choose: regular, midgrade, and premium. Understanding the basics of these three gasoline grades is a necessity for anyone who sells fuel to the public.

History of graded gasoline

In the early part of the 20th century, engine technology was improving rapidly as more and more companies were getting into the automobile and aviation industries. These companies were producing engines that created higher levels of internal compression to produce more power.

Unfortunately, these more powerful engines had a tendency to knock when running at full power. This knocking occurs when the fuel within the engine ignites prematurely and can happen when temperature or pressure becomes too high. The explosion causes a shockwave that makes the knocking sound that a driver hears. That shockwave also does damage to the engine internally, thus shortening its useful life significantly.

Research found that adding lead to gasoline helps to increase the pressure and temperature at which ignition occurs. This increase helps to prevent premature ignition and the knocking by improving the octane level of the fuel.

By the 1920s, oil refineries started adding lead to gasoline to help improve the performance of automobile engines and to prevent the damage caused by knocking. Around the same time, refineries started selling gas by grade. The higher the grade, the better the octane rating.

Today, lead is no longer added to gasoline sold in the United States due to environmental and health concerns. However, the legacy of this practice continues today with the ongoing use of graded gas.

The basics of gasoline grades

Every drop of gasoline sold is derived from crude oil, no matter what grade it is. The grade depends on how the refinery treats and processes the crude oil. The different treatments and processing affects the octane rating of the gas produced.

The octane rating measures the performance of fuel. The lower the octane level, the easier the gasoline will burn. The higher the octane rating the more compression and heat the fuel can withstand before igniting. Higher performance engines require higher octane levels to perform as the engine manufacturer intended.

There are three types of gasoline grades generally available in the United States. Regular gas has an octane rating of 87. Plus or midgrade gasoline has an octane of 89 and premium has a 92 octane rating. Other grades may be available in certain locations. The exact grade of fuel a consumer needs to purchase is determined by the vehicle’s manufacturer.

Kendrick Oil carries all grades of gasoline for our customers. If you have questions or need information on any of our fuel products or services, give us a call at (800) 299-3991. You can connect with us via email through our Contact Us page.