Gas octane?

I just found out my wife has been putting in the cheap stuff. I always out in the middle one. what kinda damage has been done... an can I fix it?
Gas octane?
need more info, what kind of car, which cheap stuff?


85.5 or 87
Gas octane?
What does the manufacturer recommend? Using higher grade is a waste of money. If the engine runs on the lower grade without "pinging" then there is no damage done using the lower grade. If the engine knocks or pings on the "cheap stuff" there is the possibility of causing internal damage such as a cracked piston, which could lead to disintegration of the piston and major engine damage.
Reply:As high as gas is these days, I dont think anyone is using high grade. Consult your manual. When you see it at $4.35 you say nah.
Reply:read the owners manual with the wife and show her the recommended fuel and the warning. lower than recommended octane is not a big deal, with low octane in a car but a truck is different. I could go into octane and what the rating means but suffice to say under heavy acceleration or towing the engine could ping/knock but today's cars will compensate by retarding the timing don't be a retard the engine will last longer. if its a lease who cares?
Reply:Unless you're driving a high compression vehicle, very few stock automobiles require high octane, you shouldn't mess with higher octane gas. In spite of what some kids convince themselves of, the octane rating is absolutely nothing related to the temprarature of gas when it burns. It is very strictly a percentage of octane molecules versus heptane. Heptane ignites under compression sooner than octane does. Higher octane gas is used ONLY when you want to avoid pre-ignition which damages the engine because it's trying to expand while the engine is still compressing it. The 104 and higher octane gasses are not 104% octane, they are a lead-based gasoline and lead acts as a stabilizer so the effective rating is over 100.





Use the lowest rated gasoline you can find that doesn't cause pinging or knocking. Stop wasting your money.
Reply:no damage whatsoever if your car was built to run on 87 octane, if you use 89 you are just wasting your money, look in your owners manual to see what is recommended.