Have you recently moved to the country? Have you wondered why there are three types of gas sold at each gas station? Which one is the best suitable gasoline grade for your car 87 (Regular gas), 89 (Plus gas) or 92 (Premium gas)and why?
The classification of gasoline is based on their "octane" ratings. They are graded as:

  • 87 Regular
  • 89 Mid-grade or Plus
  • 92 Premium

What is Octane Rating?

Octane rating is used to judge the volatility of gasoline. Lower the rating, easier it is for the gasoline to burn. It is based on the antiknock index that represents the gasoline's ability to resist pre-ignition, or engine knock. Higher the octane rating, lesser is the knocking.

Does Octane rating depend on the kind of Car or Automobile?

Yes. Most "power train control modules" have inbuilt adjustments for octane rating, for the most efficient burning of the air fuel mixture. Engine octane requirement is set by the engine design, which operates at optimum settings. Hence a higher octane will have no extra affect on it.

What Gasoline Grade should I use?

There is no advantage in using a higher octane fuel. Stick to the manufacturer's recommendation for fuel requirements till knocking occurs. If your engine knocks because of the conditions you encounter, use a higher octane fuel.

It is a particularly thorny issue to evaluate different gasoline grades. In most cases many groups suggest that the expensive gasoline is good for the automobile. It is not true that higher the rating better is the gas. You will be just throwing away your money for the higher octane fuel. For most cars the right octane is "Regular". It is best to read your car's manual and use the recommended gasoline for normal operation of the vehicle.