700 Mile Tank

I have about 3500 miles on my 06 Prius. I live up here in New England with lots of hills and commute 35 miles to work via an often traffic-jammed highway. Three years ago, a friend of mine got me to agree to be a little more green about my vehicles when I told him that when gas got to be $3.00/gal, I would consider a car that got good gas mileage. Much to my surprise, one of my other cars, a BMW M5, showed an overall speed average of about 41 MPH since new, so I figured that my mix of highway and city was probably in the range of the Prius' sweet spot. I had almost forgotten about my friend when he nailed me back in April with gas prices right at $3.00/gal. Rather than listen to him whine, I dragged him to the nearest Toyota dealer and ordered one on the spot. I took delivery less than a month later, in the middle of May.

Some random musings:

I haven't done any spreadsheets, changed to synthetic oil, bought CAN View or done the full electric mode switch mod, but I can say that I've averaged about 52-53 MPG since new. I do run 42/40 PSI in the tires but can't be bothered wasting time trying to figure out the impossible permutations and combinations of an expandable bladder tank and how much it holds on any given day, at any given temperature, with how many clicks of the filler nozzle trigger at such and such gas station. My worst tank was a 500 mile highway trip, hydroplaning on plenty of standing rain water on the road, where I set the cruise control to 60 MPH and averaged 49.2 MPG with my wife and son in the car.

I usually fill up the tank by carefully cramming as much in as I have the time and patience for, and watching gas belch from the filler neck and down the side of the car. As such, this last tank got me 703 miles at an indicated 57.9 MPG in mixed, normal driving. Yes, I know that's a bit over 12 gallons of gas, but when I filled up, it took 12.835 gallons, of which maybe a tenth ended up on the ground after the fact. Temperature during the last two weeks here has been in the low to high 80's. The gas gauge is not only nonlinear but nonrepeatable as well. On this particular tank, I ran about 220 miles before the first bar on the tank gauge disappeared. At the emply end of things, the second to last bar disappeared at 605 miles, leaving only one solid bar. At 665 miles, it started blinking, and I drove another 38 miles, to 703 before I filled up. I have no idea what would happen with this hybrid vehicle if I ran out of gas; would it just stop, or try and run on the batteries till they died, or what? Nonetheless, I carried a gallon of gas in a can for the last hundred miles just in case.

Doing the math, I might be able to get 750 out of a tank at 60 MPG with 12.5 gallons on the tank. Maybe I'll just leave the extra gallon in the back for a while longer.