What's the difference amongst 87,89, 91 gasoline?

Question

What's the difference amongst 87,89, 91 gasoline?

Answer 1

those are the octane ratings of the gas 91 being the best gas gets the best gas mileage-burns cleaner and more efficeintly but costs more per gallon.

Answer 2

the difference between 87 and 89 octane gas is very slight, and in my opinion not worth the extra money, seeing as how it is only a little more concentrated.

Where as 91 octane should be used for higher end cars, which need to run on more pure gas.

Answer 3

That is the octane number.  The higher the number, the higher the octane, the higher the price.  

Answer 4

Contrary to widespread belief, the octane rating doesn't indicate how much power the fuel delivers; all grades of gasoline contain roughly the same amount of heat energy. Rather, a higher octane rating means the fuel is less likely to cause your engine to knock or ping. Knock, also known as detonation, occurs when part of the fuel-air mixture in one or more of your car's cylinders ignites spontaneously due to compression, independent of the combustion initiated by the spark plug. (The ideal gas law tells us that a gas heats up when compressed.) Instead of a controlled burn, you get what amounts to an explosion--not a good thing for your engine. To avoid this, high-octane gas is formulated to burn slower than regular, making it less likely to ignite without benefit of spark.

The majority of cars are designed to run on regular gas, and that's what the manuals tell the owners to use. Higher-performance cars often require midgrade or premium gas because their engines are designed for higher compression (higher compression = more power), and regular gas may cause knock. If your car needs high-octane gas, the manual will say so.

Answer 5

the higher the number the more octane

Answer 6

These are octane levels, basically the refinement time, if your car needs a higher [cleaner] level then use it, if not just a waste of money. 87-murky 89-cloudy 91-clear. [Diesel]-fryer grease.  Kinda like alcoholic drinks, beer, wine, champagne, all will get you drunk but at what price?

Answer 7

higher the number the higher the octane some cars with higher compression need higher octane.