kevin_rf said:
We all know that you should use the lowest octane gas you can obtain (87),
I was wondering what expereinces people have had with different brands (ie. Hess, Mobil, Sunnocco, ect.)
The reason I'm asking is I've switched over to Hess gas vs. Shell and I noticed a mileage improment (~46/47 MPG to ~49/50 MPG).
My current tank is some no name gas and the the car is claiming 54 MPG for the tank
I was wondering what experiences others have had ...
btw. PriusOnline, welcome back
The big question is... How many tanks of each did you compare? And were there any major other differences, like warming up from near-freezing to the mid-50s between switching?
One of the biggest downers for mileage is 'oxygenated' gas, or gas that has a percentage of ethanol added. In some locales, it's mandated by law during the Winter, or even all year. (For example, I know someone that lives in very Northern California, and drives into Oregon to get non-oxygenated gas.) Ethanol makes the gas burn cleaner, and even gives a little more power, but at the expense of efficiency.
Someone posted either on here or PriusChat a few months ago about testing his Prius on E85 (85% Ethanol, 15% gas; the stuff GM's promoting all over TV now.) He said it had a LOT more power, but dropped to the mid 30s for mileage. (The bright side is that at that point, you could probably bottle the exhaust and sell it as 'purified air' to Los Angelenos...

) Oh, and it popped on the engine warning light, because the engine wasn't used to running that richly. It SHOULDN'T cause any long-term damage, though. (Dammit, I want to see a diesel Prius. At ~70 MPG on biodiesel, it would be the ultimate green machine.)
Also, in most places, Arco's gas is always oxygenated. That's why they're usually cheaper. They sell the exact same blend of gas everywhere. (On that note, my current tank of gas is Arco, and I'm getting better mileage than my previous 3 tanks. That could be due to the said warming effect, too, though.)