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Understanding Grades of Gasoline and How they Affect Vehicle Performance

When you wait to fuel up your vehicle at the pump, do you ever wonder if jumping from the regular unleaded to premium gas will really make a difference? Depending on the type of vehicle you drive, you were likely instructed on the grade of gas to use when you purchased the vehicle. But, maybe you’ve never really given much thought to the other types that exist at your local refueling station or their octane rating.

An octane rating is what measures the fuel’s ability to resist knocking or “pinging” during combustion, which is caused by the air and fuel mixture that detonates prematurely inside your engine. In Canada, octane ratings include 87 (Regular), 89 (Mid-Grade), 91 (Premium) and 94 (Super Premium). You see this rating displayed in large black numbers on the pump. Generally, the higher the octane numbers the greater the fuel’s resistance to pinging during the combustion process.

Using the Right Octane Matters

You should always use the octane recommended by your vehicle’s manufacturer. Not all vehicles use the same octane – some may require Premium, while others can use Regular. Most vehicles are designed to run on 87 octane, but others do require a higher grade depending on its engine.

Higher octane fuels are typically recommended for engines that have a higher combustion ratio or use super or turbocharge energy to force more air into the engine. If a higher octane is recommended for your vehicle, using it will boost performance and overall fuel economy.

When selecting the octane at the pump, here are a few things to keep in mind:

Don’t Use a Lower Grade Then Outlined in the User Manual

You may be tempted to use lower octane levels to save money at the pump. However, using that lower rated fuel can actually cause your vehicle’s engine to run poorly and could damage it, as well as its emission control systems over time. If your vehicle is new, using that lower octane could also void your manufacturer warranty. You will also notice a decrease in gas mileage and engine power. To get the most out of your vehicle, fill up using the recommended type of gasoline. It is also recommended that you do research about a new vehicle before purchasing it to understand its requirements and the potential costs involved.

Using a Higher Than Recommended Grade

Sometimes, using a higher octane rating may improve gas mileage, but it depends on the vehicle. Higher octanes improve performance and can reduce carbon dioxide emissions during severe duty operations, such as towing. However, under normal driving conditions, it will do little to nothing for your vehicle. Rather than wasting your money with the hopes that your engine and exhaust system will function better in Calgary, stick with the recommendations in your owners’ manual.

Consider the Cost

Higher octanes do cost more, but that is because the fuel components that boost the octane rating are more expensive to produce. If your vehicle requires mid-grade to premium gas, it is well worth the cost. Not only will you reduce how often you need to fill up, but you can also minimize costly repairs associated with using the wrong octane for your vehicle. To avoid engine repairs, Calgary residents should consult their owners’ manuals before filling up.


Some gas stations will have ethanol that you can add to your vehicle to boost the rating. Ethanol does have a higher octane rating (at about 109) than gasoline. Some refiners will blend it with gasoline to increase the rating – and you may find blends with 10 to 15 percent ethanol. However, adding ethanol on your own is not recommended because most grades of gas already include some level of ethanol.

85 Octane

Some areas with a higher elevation may carry 85 octane at the pump, but modern gasoline engines should not use it. 85 octane is ideal for older vehicles with carbureted engines; not newer ones. Consider this when filling up and stick to the gasoline that is right for your vehicle.

Contact us for Exhaust & Engine Repairs in Calgary

To get the most out of the gas you use, you need to maintain your exhaust system in order to improve performance, reduce emissions and increase fuel economy. If you notice a decrease in your gas mileage or your vehicle seems louder than normal, bring it to Speedy Apollo where we handle exhaust system repairs for Calgary residents.

By properly maintaining your vehicle and its engine, you will reduce the need for repairs in the future. However, when you do need them Speedy Apollo Auto Service Centres is available to assist you at our 2 locations across Calgary. Bring your vehicle to us for engine and exhaust system repairs.

Contact us today at our locations including Midnapore and Forest Lawn.

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