What octane ratings really mean for your car

By: Akhtar Hussain, Director of Refined Fuels Marketing, Refined Fuels in Fuel Efficiency
Load up the snacks and crank up the tunes, because summer road trip season is officially here. But while you’re at it, don’t forget one important detail for your cross-country caravan: the fuel that powers it. Summer trips mean long hours on the road hauling heavy gear.  Towing loads like boats and campers can be especially taxing on the family car. So before you hit the open road this summer, make sure you’re using a fuel that’s been engineered to meet your vehicle’s needs.

When you’re at the gas pump, you probably see multiple grades of fuel to choose from. Fuel grades like regular, plus and premium are dictated by their octane rating.  Many people assume a higher-octane gasoline will automatically give their vehicle better mileage or more power, but that isn’t necessarily the case. So what do those different octane ratings at the pump really mean?

Why octane ratings matter for your engine
Gasoline-powered motors work by igniting a mixture of air and fuel at carefully timed intervals with a spark plug. Prior to each combustion, this air-fuel mixture is compressed, allowing its maximum energy potential to be extracted.

But because compression creates immense heat, a fuel must be able to withstand extreme temperatures, otherwise it can misfire prematurely. This issue, where the air-fuel mixture combusts spontaneously instead of from the spark plug, is known as “knocking,” named after the sound it produces. 

An octane rating is simply a measure of how heat resistant a fuel is in order to prevent knocking. In other words, octane doesn’t enhance combustion — it prevents the air-fuel mixture inside an engine from igniting before it’s supposed to.

The higher a fuel’s octane, the more resistant it is to knocking. If you hear knocking, you could be using the wrong octane for your ride. The recommended octane rating varies by vehicle, so always consult your owner’s manual to determine which is right for you. Some vehicles require a higher octane rating because they have what’s known as supercharged or turbocharged engines that create higher compression levels.

Which octane rating should you use?
You should always use at least the minimum octane rating recommended by your vehicle manufacturer. Using a lower-octane fuel than required can cause knocking and will prevent your vehicle from meeting its stated fuel economy. Over time, filling up with fuel that’s not up to your vehicle’s requirements can damage both your engine and emissions control system.

On the other hand, using a fuel with a higher octane rating than your vehicle requires will never do any harm, but it won’t necessarily benefit you either. Higher-octane fuels can potentially increase performance in some vehicles when towing heavy loads, especially in hot summer weather. Under normal conditions, though, the best octane to use is the one recommended by your owner’s manual.

No matter which octane level your vehicle requires, you can depend on CENEX® TOP TIER™ DETERGENT GASOLINE to fuel your summer road trips. With a multifunctional, industry-leading additives package that comes standard in every grade, Cenex gasoline gives you worry-free, fuel-efficient miles on the road. LEARN MORE about TOP TIER Detergent Gasoline contact one of our NuWay Cooperative Certified Energy Specialists Riley Schwieger or Haley Ammann at 800-445-4118. Now who wants to ride shotgun?