What's the difference between 87, 89, and 91 octane gas?

The additives.
What's the difference between 87, 89, and 91 octane gas?
yes there is a bit of but some times not that one can tell... you looking to know which to use then you buy a tank and mark the miles down and do this with a few types and brands.. the one that gets you the most miles per tank is the one you want to use be it the high or low ..... not all cars run the same car maker will recommend a type but its just that.. only the driver will know which one gets them the best mileage... so you have to test it out and mark it down to know which runs the best for your driving and your car
What's the difference between 87, 89, and 91 octane gas?
The higher the octane the HOTTER it burn. Read your owner manual and follow what they recommend. If you use higher octane gas when the manufacture recommend the lower octane. You'll be burning your $$$ away. Normally, the higher octane is used on high performance engines (Lexus, Mercedes, your high end vehicles) or high compression engines as just motorcycles.
Reply:the higher the octane in your fuel, the hotter the fuel burns. Generally, you can put lower octane gas into a car that specifies high octane, but you shouldn't put higher octane into a lower octane tank except in scheduled maintenance to clean out your fuel injection system (as specified by your mechanic).
Reply:High octane DOES NOT MEAN HOTTER BURN !! Octane ratings are related to the fuel's likeliness to predetonate (knock). The higher the octane, the less likely to knock. If your car is not a high performance model (high compression engine), and runs fine (normal mileage and power) on low octane, save the $ and buy the cheap stuff.
Reply:Difference between the fuels is in the resistance to pre-ignition. Pre-ignition is when the fuel mix in the combustion chamber explodes before the spark plug fires. It causes a pinging or knocking sound you hear when accelerating. If 87 octane "pings" then try 89 octane or 91. Keep in mind that your vehicle should not ping using the manufacturer's recommended octane. If it does there is likely a problem with the emission system, or carbon buildup in the combustion chambers, or engine overheating.
Reply:a fuels octane rating is very simply the fuels ability to not ignite prematurely under compression and heat the lower the rating the lower the fuels ability to withstand preignition higher compression ratio engines need a higher octane rating or the fuel will detonate prior to the proper time for ignition IE. pinging there are many factors in the combustion chamber that can cause this ,carbon build up on the tops of the pistons is the most common cause this increases the compression ratio and can cause pinging they would like you to believe that the higher octane gas fixes the problem but in reality you are treating the symptom not the problem a good fuel system cleaning will solve this and back to the 87 Oct you go. if you have a sports car with a high comp engine then the higher octane is required because the engine is built with a high compression ratio for that manufacturers will recommend 93
Reply:I AM TRYING TO START A FLAME WAR!!!


octane is resistance to burn


the greater the octane number the greater the resistance to burn so when it does catch fire it is more explosive, and a little more power, that is why it is used in higher compression engines(racing) the engine will not "fire" the fuel like a diesel before the spark plug fires causing detonation,


lower compression engines do not see much advantage to using high octane fuels . althogh some people feel it cleans the carbon out of daily driver vehicles