Understanding Gas Grades at the Pump

A trip to the gas station usually is a fairly automatic procedure, where we pay, select our gas grade, and pump to our desired level before leaving. While we see it every time, many of us to do not fully understand what separates one grade from another. Some people believe it’s a matter of quality difference or that you get better gas mileage with the higher octane levels.  Maybe your car manual tells you to use a certain type, and you just automatically use it without thought as to why your car may require a higher octane level. Let’s take a look at gas grades to see what’s behind the numbers.

How Engines Use Gasoline

Understanding the basics of how engines use gasoline is the first step to understanding octane levels.  In a four-stroke engine, a piston completes four steps. The first step is called intake, where air and gasoline enter from the top of the cylinder and a piston, which is running a constant circular motion within the cylinder, begins its cycle by starting from the top of the cylinder and descending to the bottom.  Within this descent, the gas and air is compressed and then ignited by the spark plug. This is where the octane rating of gasoline is important, as the gas and air mixture can spontaneously ignite due to compression before being ignited by the spark plug. When this spontaneous ignition occurs, it is referred to as knocking.  This is an appropriately coined term, as it literally sounds like a knocking noise when this happens.  Knocking can be detrimental to your engine, especially if it persists, but, luckily, there is often an easy solution: refueling with a higher octane level.  Higher octane levels simply allow for more compression before knocking occurs.

Which Octane Grade is Right for My Vehicle?

Reading your manual is the key to knowing which level of octane you need for your vehicle or equipment. The majority of cars just need regular octane, but higher-performance cars tend to require a higher octane level. When in doubt, your ears will let you know if you are using too low of a grade, as knocking is a real indicator. 

The Difference Maker: Quality Fuel

Many people believe that if their car uses regular octane, that giving it a higher octane level is almost like giving a treat to their automobile’s engine. You might hear that it improves your automobile’s performance, gas mileage, or that it better cleans your engine.  The fact of the matter is that if your car requires regular octane, a higher octane will not improve its performance or gas mileage. Additionally, all gasoline grades are required to contain fuel additives that target harmful engine deposits.  Chevron and Texaco fuels use Techron®, which not only helps lower emissions, but also is the leading additive in helping keep critical engine parts clean.  As such, Techron has been designated as a “Top Tier Detergent Gasoline.”

Bottom Line

Stick to your automobile’s recommended octane level. There is no advantage to going beyond that level, but there certainly is a disadvantage to going below the recommended number. The focus, instead, should be on using a quality fuel brand. There is a marked difference between fuel additives in your gasoline that help keep your engine clean and free of deposits, which affects the longevity and performance of your engine. Not all fuels are created equally, and choosing the right one is the simplest step you can take to improving your vehicle's performance now and in the future.

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