I’m sure you’ve wondered at least a few times when filling up, if it’s worth spending more on premium fuel. Most drivers choose to bypass the premium and use the cheaper regular unleaded gasoline. But did you ever wonder what exactly is the difference between the different octanes?
Most gas stations in the U.S. offer three different octane levels:
- 87 – Regular
- 89 – Mid-grade
- 91 to 93 – Premium
An octane rating, according to Exxon Mobile, measures the fuel’s ability to resist engine knocking, or pinging. The higher the octane, the greater resistance the fuel has to pinging during combustion. Certain gas stations may offer up to five different octane ratings. Other places may call their mid-grade “plus” or “special” and their premium “super”. If the description confuses you, just look at the octane level.
The Benefits of Regular Unleaded Gas
The single biggest benefit of using regular unleaded gas is the cost savings. Regular gas typically costs around 30 cents less per gallon than premium. Over the year, depending on how often you fill up, that can lead to significant savings.
When talking about the effectiveness of regular gas, the Federal Trade Commission says there are no advantages to using premium gas in cars that don’t require it. The FTC states that using a higher octane on cars that don’t require it will not lead to better gas mileage or to the car running cleaner or faster.
You can find the recommended or required gas for your bought or leased car in the owner’s manual. Today in most newer cars, the engine control systems could compensate for low octane by monitoring knock activity and adjusting ignition advance to avoid knocking. Basically, today’s sophisticated cars can effectively tune their engines on the fly.
When to Consider Mid-Grade Gas
Mid-grade lies somewhere between regular and premium. There are very few cars that require or recommend mid-grade gasoline. People whose cars require premium, will sometimes use mid-grade to save money but still use a gas that’s a higher octane than regular.
Premium Gas – Is It Worth the Cost?
Different states have different regulations regarding what represents premium, usually it starts at 91 and goes to 93. The only cars that require premium gas, are cars with a high-compression or turbocharged engines, to prevent the engine from knocking. If your car does not require the use of premium or has a low-compression engine, than there is no benefit to using premium.
Higher-compression engines require the higher octane so that the fuel doesn’t pre-ignite in the combustion process and damage the motor. Octane slows and controls the detonation of the fuel during the compression and detonation of the fuel.