Ok, I bought a 2006 #7 silver at January 2nd, as everyone here did, I got a free tank of gas per purchase. Only 2 bars left, so I drove to shell gas station, and refilled it last night. For the first free tank, the best MPG I got was from highway, about 54 mpg, but regularly, I only got around 38-42 in city. After I refilled with shell oil, guess what, I got 56 mpg in the city!!! I have not tested for highway, but 56 in city, esp in cold winter!!!! I am so happy. I am really wondering what kind of gas the dealer provide to us. With the shell gas, the mpg jumped from 38-42 to 56! It is really a big surprise to me. What you guys got with your first free tank? Did you see any improvement with higher quality gas like shell?
Definitely- Shell gas vs. Imperial (Esso) shows a consistent MPG gain.. I normally use Esso gas simply because it's convenient (there's a station right down the street from work) and because I'm on a fleet program where I get a discount on all Esso gas purchases. Recently, since the gas prices have come down to a bit more reasonable level, I decided to try an extended test with Shell V-Power premium gas and over the last 5 or so tankfuls, I'm averaging 4.6L/100km in my Classic Prius, in a temperature range of -5 to -15 C.. This is actually *better* than my summer mileage. Some of this I can attribute to the Michelin X-Ice tires, which I chose to be "minus sized" width, but higher profile for better snow performance and lower rolling resistance, but this accounted for my expected winter mileage of about 5.5-5.6L/100km with Esso winter gas formulation going down to nearly summer mileage of 5.1-5.3 L/100km (I normally get 4.8-5.0 in the summer), so the only explanation for the 4.6 that I've been seeing for the past few tanks has got to be the Shell V-Power gas.. I know that the normal explanation is that Premium fuel actually contains less energy, and certainly, the other times I've tried other brands of premium fuel, I didn't notice any difference, but there's something about Shell gas that doesn't fit the conventional mold..
My first fill up after the dealer tank calculated out about 6 mpg less than the MFD showed. I suspect it wasn't quite filled up initially. The next tank calculated much closer to the MFD value. fd
