Octane and my car, what octane fuel should I put in my car

In general, for a engine requiring 87 octane gas it does not matter what type of fuel one uses in a car. Most cars are built to run on 87 octane fuel, and giving them higher octane fuel will in most cases provided no benefits (in a normal working engine with no defects.) It’s not necessary, it provides no additional benefits, and it will cost more and, in some cases, could actually lower your fuel mileage.

However, some people believe that what kind of gas is used, seem to make a difference in car performance. This can generally be attributed not to the gas but to types of additives in the gas. Thus for some people, there can be a difference between one company’s brand and another company’s brand. For many, this makes no difference either.

Some cars do require higher octane gas. The owner’s manual will inform you of this fact. For example, Some high performance cars, such as Corvette, have engines built with high compression engine, as do many luxury or sports car, they require an octane rating that is higher.

Generally, the purpose of higher octane gas is to prevent knocking or pinging in the engine. The reason is, the higher the octane the more it can be compressed before it spontaneously ignites. Thus, with high compression engines, a higher resistance to spontaneous ignition is necessary. Lower octane fuel can cause pre-ignition or a "knock" in these engines. Spontaneous ignition knocking can damage the engine. Knocking sounds are caused by the sudden ignition of fuel, which occurs almost instantaneously. The sound reverberates throughout the cylinder causing an audible ping or knock sound.

If you can eliminate knock by using higher octane gas, then it may be worth the extra money to do so. Like I stated before, higher octane fuel is required for higher compression engines. Economy engines that produces a knock on lower octane fuel and then the knock "goes away" with higher octane fuel can mean that there is carbon buildup on the pistons, caused by poor quality fuel or lack of maintenance. This sometimes can be remedied by cleaning the tops of the pistons with a chemical cleaner.

Occasionally one has to ignore the manufacturer’s instructions and dig deep for the high performance gas.