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What quality of gas should I buy?


I just purchased a 2010 Prius which is a hybrid. The owners manual says to use unleaded (octane rating 87 (research octane number 91)or higher. Gas stations sells unleaded gas as regular, super, and super duper and each quality costs 10c more than the lower rating. Is it best to buy the super duper?

All gas pumps have octane ratings for each grade of gas. Buy the cheapest one that meets the Prius RON octane requirement.


You don’t need anything but the regular. The higher priced gasoline will do nothing except cost more money. I have two Toyotas–a 2003 4Runner and a 2011 Sienna. Both manuals say to use 87 octane(regular) or higher. I use the regular in both vehicles. Once, on a trip, I accidentally put the next higher grade in the 4Runner. It didn’t make a bit of difference in the mileage for that tankfull. I just wasted $2.00.

Buy 87 or higher. No need to buy higher however. In fact is it (remote) possible that using higher octane may cause some damage. The different grades are not differences in quality, or power, but rather a difference in how fast the fuel will burn.

Many high power engines require a fuel that burns slow so they need to buy a higher octane (slower burning) fuel.

Buy whichever gas will fit in your tank.

Can poor quality gas still have a high octane rating?

Quality and octane are not interchangeable terms.

Exactly my point,but if I would have come out and said so,argument,at times it is best just to lead and let the conclusions come as they may. Why was this not pointed out at the beginning?

You can have high octane fuel that is full of debris,that is my definition of low quality fuel.Be be prerared for alot of this in the near future,one of my classes this semester is “Logic 120”, do you think it will help me win a debate with Mike? or can anyone win a debate with Mike?

The numbers reflect the octane, not the quality. The octane is a measure of how resistant the fuel is to self-igniting when compressed (which is bad for the engine). You don’t need anything higher than what the manufacturer specifies.

There was a time in the past when higher-octane gas might have had better additives, but this is no longer the case.

one of my classes this semester is “Logic 120”, do you think it will help me win a debate with Mike? or can anyone win a debate with Mike?
I think that you (and the rest of us) might do better if Mike took the Logic 120 class.

Best advice…use brand name gasoline 87 octane…regular…

Your Prius does not burn enough gasoline to worry about price shopping. Just fill up at a brand-name high volume station. Don’t confuse octane with quality. They are two completely different things…Gasoline is a consumer commodity traded on global commodity exchanges. When sold at retail, it must meet certain minimum quality standards. The “unbranded” outlets you see on the street are usually owned by major oil company distributors who need a little more “shelf space”…

Octane is not a measure of the quality of gasoline, it is a measure of how fast it burns. High octane burns slower. Many performance cars need higher octane. Read the owner’s manual to find out what octane you need. More than needed does no harm other than it cost more. It also does no good.

Sorry oldschool…but you’ve PROVEN you’ll NEVER have the logic…