im about to fill up my firs tank on my prius , but people got me confused, they said i should use higher octane than 87 , when manual says it should be 87 otanes,pls help , wich one gives you better performanse? I mean talking about better MPG THANKS
You now have to decide, who knows best: 'people' or the company that designed and manufactured the car.
At the risk of being crucified, higher octane only helps if you have a lot of carbon buildup on the tops of the pistons, which results in higher compression ratio and hot spots. That can cause pre-ignition under heavy loads, which the ECU will notice due to the knock sensor and retard timing accordingly. Retarding the timing results in lower MPG. Using the next higher grade of gas (89) may result in higher MPG to the point where the cost/benefit makes sense under this scenario. However, I would only expect to see this on a car with 100,000 miles or more. This is why some people say they get better MPG with higher octane, but get raked over the coals by everyone else, because the other side of the argument is that higher octane does not mean higher energy content. The vast majority of Prii should use 87 octane, or 86 if at higher altitude. If you can find ethanol-free gas, that will give you better MPG due to higher energy content by volume.
I've filled up my 2009 prius a few times and I only use 87. I've read on the forums higher octane won't do you any good and if you think about it, it makes sense. I like Shell gas but I have no data to suggest it's any better than the other big stations. Good luck with your car.
Use any gas you want. I recommend 100% gas (avoid ethanol) but the car will behave OK with even the cheapest gas you find. See http://priuschat.com/forums/gen-iii-2010-prius-main-forum/98236-there-recommended-gas-prius.html for plenty of thorough discussion.
I have used Chevron's 87 Octane on all my cars for the past 15 years. I also make sure to add a bottle of Chevron's Techron Concentrate Plus to an almost empty gas tank every 2,000 miles. Our Fuels: Fuel Additives: Techron Concentrate Plus AND unlike other gas stations that have additives, Chevron's gasoline contains the same amount of Techron whether you buy regular or premium gasoline. Chevron - Trust in Techron
You're in Jawga, so it's unlikely that you're going to find yourself tooling along above 5000'. Currently, there are only three states that require ethanol in gas (Minesoooodah, Missouri, and Hawaii---source wiki, TIFWIW) although it can be tough for find gasoline without alcohol in your area. I live in the Gulf South, and there are a few mom and pop stores that (say that they) sell E0. It's 10-15 cents more than E-10, and they're favored by the motorcycle community, some gear-heads, and folks that just hate E-10 gas but are not sure why just yet. I usually aviod them for several reasons, including the fact that nobody reeeeally checks to see if they're selling E-10 or E-0. I've used E-0 for a couple of tanks in 'my' Prius. I don't buy the gas for this car, so cost is no object. I saw no difference in fuel economy over a two tank span (TIFWIW.) Mostly, E-10 gas is a non-issue for Priuses. To be sure, there are people that will tell you that it will destroy your car, just like there are still people out there that will tell you that Priuses have $12,000 batteries that have to be replaced every 50,000 miles. Here's the "real" deal. Buy fuel where you want to and use 87. I will say that I prefer so-called "top-tier" stations because I suspect that their equipment (tanks, pumps, filters) are in better shape than some of the seedier mom and pop places. The places that I frequent sell a LOT of gas, so there's little chance of having to put with sullied fuel. Also, the rest rooms are cleaner, and the coffee is fresher. DON'T use E-85. Good Luck!
My Prius has 115k. I always use 87 octane except when I visit my sister in AZ... over there is a station owned by a friend and I get a free fill-up. I've used 89 and 92 and noticed no difference in my mpg (and I go there w/a nearly empty tank to take full advantage of the freebie so there is little mixing).
