Thanks! How fun is it to discuss how bored I am with only getting 45 MPG... Can't wait for the next Prius or some kind of breakthrough where we get a 80-90 MPG car...

 

Does the Seattle area mandate the use of reformulated fuel with 10% ethanol or are you still getting MTBE additive? I've lost about 3-5 mpg now that MA has changed over to reform fuel with ethanol and I can't seem to get much more than about 51 mpg no matter how hard I try.

 

Now that you mention it, the gas stations I frequent all have 10% ethanol. If I were attempting to be a hypermiler, I might have noticed before.

 

I don't think so, but the only evidence I have is that my MPG has been consistent for going on 4 years now. I've noticed no real drop between what I was getting in 2003 versus now.

 

I have a MAJOR issue with this and was going to post my own thread about it but was sidetracked reading old threads (kind of entertaining) and actually came across this in the process.

This morning I began recording the dash millage at 10 mile increments and plan to do so through a series of 500 to 550 mile tanks. In the past year or so I've seen a pattern. From 0 to about 200 miles the dash FE looks great - upwards of 50 MPG, on occasion well over. But between 200 and 250 miles it begins to plummet. The dash will begin showing somewhere between 44 and 46 MPG, and it's been this way on almost every single tank.

If you're resetting your trip meter on segments then you're taking too small of readings to get any kind of remotely accurate measurements. Furthermore the dash is wrong. I've seen people say the dash was as much as 3 MPG high (Tim, "usually 49 on the meter, 46 actual") and 3 MPG low and both inconsistencies on the same car in the same conditions. 3 MPG high on a 46 MPG tank is a 6.52% variance on correctness ... WHAT!?!?! If that percentage holds true then people claiming 65 MPG from the dash are probably actually getting closer to 61 MPG. And if you're stringing together segments and calling high readings from a series of short segments any kind of lifetime then your actual mileage is dramatically lower. Tim is making the same out and back trip and seeing a difference of 15 MPG on later trips. That's over 20% lower when the dash starts giving something that's only wrong by 6.52%.

Case in point, Tim's data:



Resetting your trip-o-meter is going to give you unusable results. Relying on the dash is going to give you inconsistent results. The only way to know how much fuel you are burning on a regular basis is to measure the miles you drive and divide them by the amount of fuel you put in the vehicle.

My dash usually says something like 46.4, but my actual is more like 44.2. I don't do anything special when I drive and I drive 5 miles in town and 25 miles on interstate one way every day. It's mostly flat with a couple minimal hills. I'm going to record 10 mile increments according to the dash for several tanks (about a tank a week) and see how it charts out.

 

i have on occasion used segments, but found it to be more work than it's worth. and i may describe on the boards that i am getting a 65MPG or whatever, but until i see what the actual gas usage is, i don't count that as my actual mileage.

that said, the highest i have recorded for an entire tank is 65.18, with my summer average just about 59. minnesota winters, with the addition of snow tires, keeps me lower than i think i could do elsewhere. even so, i still manage to stay above 50 in the winter. icy roads often times act like low rollling resistance tires LOL

 

Did you check your air filter? Make sure the air intake is clear (Above the radiator).

Critters like to build nests in there and that would restrict air flow.

-C...

 

My mileage is consistantly off by 10% or so. I use the trip fcd for segments, but I use gas+miles on the odometer for my actual tank calculations. In my database entry I have been putting in what the car said in the fcd in the notes, but using fuel used and miles driven for my calculations for the tank.

Also, I have heard that over 65MPG or so the fcd starts to be pesimistic vs the optomistic at below 65mpg.

Generaly I take 10% off the numbers when I tell people what I get for a trip unless it is over 65mpg.

 

It may have been obvious, but to clarify those readings are on the same meter reset. That is, fill up, reset the trip computer, and that's what the readout is as I come and go from work. That error margin of 3 MPG is actually 3.1 MPG over the 100 tanks of gas I've recorded - always low. Measured at the end of the tank (when comparing the dash readout to the actual calculated MPG).

 

My lifetime milage is 55.3 mpg. I live on the east coast of Florida. I work at Cape Canaveral and get there by driveing through Kennedy Space Center. There is a lot of Secuity there and they run lots of speed traps. My route is perfectly flat and I use the cruise control. 70 miles round trip. 55 mph going to work. 45 mph coming home. I don't use the A/C which is tough in the summer. I aviod the interstate. Believe it or not I actually pick my route home based on the wind direction. I have three routes to pick from. It makes a big difference. Thats about it. No forced auto stops or any of that hypermiler stuff. I think it is mostly the enviroment you drive in and the gas formulation that determines your gas mileage. Also the driver. My best advise would be move to sunny Florida