Higher octane fuel can run as much as 30-40 cents higher per gallon, and many consumers have been lead to believe that the higher the octane, the better fuel economy and power your vehicle will experiance, but is this true? Can adding higher fuel grades to your vehicle improve overall fuel economy? Lets find out!

The octane number itself is actually an average between two different octane values, Motor Octane and Research Octane. The two values reference the fuels ability to resist pre-detonation, commonly called engine knock. This is important to know because engine knock is very bad for your vehicle's motor and occurs when fuel is detonated in an engine during the compression stroke instead of when the piston has reached the optimum point of travel to make the most power from the combustion of the fuel, causing severe pressure and wear on the internal components of the engine (think of it as having you knee hit back while running).

Manufacturers typically engineer their vehicles to work with all the different types of octanes available, and some higher performance, turbo charged or supercharged vehicle might require the additional octane provided by premium fuel, but that is because the higher cyclinder pressure makes the air/fuel ratio more unstable, which is fixed by the higher octane. Just using fuel of an octane rating higher than that of the manufacturer's recommendation will not increase performance, fuel economy, lower exhaust emissions or increase engine/fuel system life.

If your vehicle requires higher octane fuel and you run it on lower octane, don't kid yourself into thinking the car doesn't actually require the higher grade fuel. Most modern vehciles are equipped with a knock sensor that tells the computer to retard the timing. This will typically prevent the engine knock from happening as a retarded spark will fire later in the combustion cycle, but it's not ideal as it decreases performance, fuel economy, increases emissions and causes the engine to run hotter. In the long run, the money saved at the pump will be wasted in economy and potentially expensive repairs.

More often then not, the fuel economy and performance of your motor can lead back to the fuel itself. The different methods of blending fuels to manufacturer the specific grades of fuel is more important than the octane level. Cheaper grades of fuel tend to have higher levels of undesirable compounds such as benzene, sulfer, diolefins and olefins which are typically removed in the refinemnet process. This all costs money which is passed back to the consumer in the price of the fuel. With these compounds present in the fuel, the vehicle is more apt to develop issues with higher emmisions, fuel system sludge build up and shortened catalytic converter life, which can all affect your overall engine performance and ultimately fuel economy.

What's the bottom line? Unless your vehicle's manufacturer specifies it or if you have modified your engine with a supercharger, turbo or performance chip, then don't use the higher grade fuels unless you just want to pay more. That being said, the brand of fuel you use could make all the difference for you by extending engine life and increasing fuel economy in the long run. We're not suggesting you get what you pay for at the pump, but the higher priced fuels cost more than the quick-e-mart brand fuel for a reason.