Hey there! I'm brand new to Priuses and know very little about them (forgive me!! I do know quite a bit about non-hybrid cars!) I bought an '08 recently, and my fuel economy is supposedly averaging around 46 mpg. OG battery. NOW- by how fast my fuel tank appears to be dropping, (and I haven't yet calculated this myself- Ive only put gas in the tank twice since owning it,) it certainly does not seem to be getting 46 mpg. Can someone please tell me if the fuel "gauge" could be off, or the (whatever computes your mpg) or both, and why?? I'm honestly not versed in cars that are this electronic/computer based at all, but am a huge fan of efficiency. For reference, my other car is a (manual) '02 VW Golf TDI (diesel; it also runs on biodiesel)...which averages around 40 mpg. Thanks!!
three issues here: 1) the dash average is 3-5mpg optomistic, and the speed reads 1-2mph higher than actual 2) the gas tank has a bladder, and does not fill the same each time, depending on ambient temp 3) the fuel gauge is not linear, unfortunately 4) welcome to the world of prius quirks!
To mitigate this, you need to keep track of your distance and fuel usage so you can accurately calculate your MPG. You then need to smooth the average using a 5 tank rolling average.
That fuel tank bladder in the Gen 2 is a strong candidate for the most aggravating Prius annoyance of all time, especially in cold weather.
Yes. You combine the data for the last 5 tanks and average that. Each time you fill, the previous 5th tank's data is dropped and the new tank's data is added, hence as time goes on the average is 'rolling'.
Hardly anyone goes to that much effort. Most other people would just average however many consecutive tanks as they have recorded.
The effort is almost nil if using a spreadsheet, once the initial formula has been entered. Obviously, one does what is the easiest to do with the resources available.
"Almost nil" is still above the effort level of most drivers. Most won't use computer spreadsheets, or even a paper logbook. Mobile phone apps seem to be the most common fuel economy tracking tool mentioned here on PriusChat.
Hmmph, I thought I covered that by saying, 'Obviously, one does what is the easiest to do with the resources available.'
This! I can fill my 2006 and drive it to work for 2 days before the gauge starts to drop on the 3rd day. I have roughly a 38 mile commute one way, so that is a bit over 150 miles before it shows movement. To be fair most vehicles I have owned seem to behave the same way but not to this extreme. Most of the time for other cars it would be maybe 30 to 50 miles before the gauge moved, not 150. My bet is the manufacturers do this to make everyone have a good first impression of the fuel economy.
