Fill ‘Er Up: Know How Different Fuel Types Affect Your Car

Gasoline is the main transportation fuel in the United States. Most of us are familiar with the trio of regular, mid-grade, and premium-grade options at the pump. But you may not be aware of the reasons to choose–or not to choose–each one.

With the advent of ethanol production, the choices have further expanded. Using the wrong types of fuel in your car can do much worse than diminishing performance: it can cause permanent damage to your engine.

Fortunately, there are some pretty simple rules to follow when selecting among the different types of gas. The information below will help you select the right one to optimize performance and fuel efficiency, and protect your engine.

Gasoline Basics

Petroleum refiners distill crude oil to render an unfinished gasoline or “blendstock.” They then mix in additives to make engines run smoother or to avoid certain problems like gumming internal parts.

In the 1920s, it was discovered that adding lead to gasoline reduced wear on engine valves and engine knock, which is the uneven burning of fuel in the cylinders. “Leaded” gasoline was the primary fuel management systems for vehicles sold in the United States until 1975 and was banned for use in on-road vehicles in 1996 by the Environmental Protection Agency.

Main Types of Fuel Today

Following this, the petroleum industry started developing various octane gasoline additives. The level of octane in gas determines its heat resistance, which also prevents engine knock. And, the more octane the gasoline contains, the faster and stronger it burns under pressure.

Today, gasoline comprises isooctane and heptane. The isooctane-to-heptane ratio in gasoline determines its “octane rating.” For instance, “regular” 87-grade gasoline is 87 percent isooctane and 13 percent heptane.

“Midgrade” or “plus” fuel contains about 90 percent isooctane. “Premium” has 92 percent. These options both cost more than regular gasoline. Some companies refer to the grades in different terms. “Unleaded,” “super unleaded” and “premium unleaded” are common ones.

Your vehicle’s owner’s manual should have instructions on what types of fuel are appropriate. Most cars require “regular” or 87-grade gasoline. Using plus or premium-grade fuel in these vehicles will not improve fuel efficiency or performance. Higher octane grades also could cause damage to your engine.

For other vehicles, like SUVs, luxury, and high-performance vehicles, it is necessary to use higher octane grades. It will increase fuel efficiency and, conversely, regular-grade fuel could damage the vehicle. Some manufacturers recommend at least mid-grade fuel for newer models.

The Advent of Ethanol

Even though we have only heard about ethanol as an alternative fuel source during the last 20 years, it is not a new innovation. Henry Ford’s Model T, introduced in 1908, could run on alcohol fuels.

Ethanol is an octane booster that comes from renewable sources like corn, soybeans, and sugarcane. Today, most gas sold in the United States is E10 (10 percent ethanol, 90 percent gas).

Only FlexFuel vehicles can use high-ethanol fuels, like E85. Yet most cars built after 2002 can use blends of E15, E250, and E30. Note that there are components you can install, like the COBB flex fuel kit, that allow you to run almost any type of fuel.

One downside to ethanol is that it has less chemical energy than that derived from petroleum. For this reason, you may experience diminished fuel efficiency with ethanol blends. Also, because ethanol has a lower heating value than gas, high-ethanol blends make it harder to start a car’s engine, especially in colder climates.

Find the Best Fuel for Your Vehicle

Now that you have an idea of the different types of fuel, you can determine which one is right for your vehicle. Remember that the most important thing is to reference your car’s manual or manufacturer to see which is suitable.

We hope this information on fuel types was helpful to you. If so, be sure to check out some of our other automotive posts, as well as those on lifestyle, outdoors, gardening, and many other topics.