2010 calculated vs. computer MPG - Please post your results

[PriusRos]

Miles...Gallons....MID Mpg.....Calc Mpg...Difference
435....... 8.93.........50.0.........48.71.......3%
406....... 8.37.........51.1.........48.51.......5%
429....... 8.93.........50.6.........48.04.......5%
312....... 6.26.........52.5.........49.84.......5%

It's frustrating that the discrepancy increases with the displayed mpg (I was getting 3-4% difference when the readouts were in the low 40s). I still haven't broken the 50mpg barrier with this car!

[alfon]

306.0 miles / 6.544 gals / 49.9 mfd / calculated 46.76

323.5 miles / 6.040 gals / 55.9 mfd / calculated 53.55

alfon

[afstudio]

I have had my 2110 Prius for 2 months and I'm hovering around 40mpg. I drive mostly short distances. Is this the computer or the car? Anyone know?

[3PriusMike]

Originally Posted by afstudio

I have had my 2110 Prius for 2 months and I'm hovering around 40mpg. I drive mostly short distances. Is this the computer or the car? Anyone know?

Are you hovering around 40 mpg for the entire 2 months? Or when you reset one of the trip meters and measure for a few days do you never get much over 40 mpg? Big difference.

You should be able to get 50 mpg on some trips. But when starting cold and driving 1-2 miles if you get 30-35 you are doing well. You should be able to start cold (for CA) and drive 6-7 miles at 35mph without a lot of braking, and get 50+ mpg.

3PriusMike

[Tideland Prius]

ok I filled up today and I'm rather shocked at the difference.

4.4L/100km vs. 4.79L/100km (MFD/Calc'd)

[F8L]

Originally Posted by royrose

I agree on your fill method. Only the first and last matter. If you fill a little less after tank #3, that will affect calculation for that tank, but will be made up for with tank #4. The cumulative calculation won't be affected.

Wayne Gerdes at Cleanmpg.com believes that early cars were 6mpg over, later cars 5% over and at least one recent car was accurate.

Read his comments after his report of hypermiling with the Gen III Prius: 2010 Prius-III P&G, SHM and WS FE techniques rehashed, defined and refined - CleanMPG Forums

Thanks Roy. Post #5 on CleanMPG.com really clears things up for me and explains why I was seeing what appreared to be many "fresh off the boat" Prius' getting a large discrepency in computer vs. calculate MPG and why some of the newer owners with later build cars are not seeing such large swings.

[driv3r]

Hello to everybody on the forum. I have a question:
The prius sold in EU is rated at: extra urban 3.8/ urban 4.0/combined 4.0 (L/100km with 17" wheels) .. so how is the average calculated? it shuld be 3.9 right?
Exemple: Toyota IQ EU engine 1.0l 5MT: extra urban 3.9/ urban 4.9/combined 4.3 (L/100km) how?

European Urban cycle=4km; Extra-urban cycle=7km

So... (4km x 4.0l/100km + 7km x 3.8km)/11km=3.8727/100km... ??

For the IQ: (4x3.9 + 7x4.9)/11=4.536.. witch is close to 4.3 combined but not quite.

Any thoughts on this?

[pakitt]

Last fueling today, reported 4.9L/100km, calculated 5.44L/100km, that is, about 9% more.
Previous ones were:
- 5,1L/100km vs 5,48L/100km (7%)
- 4,7L/100km vs 4,65L/100km (-1%)
- 4.9L/100km vs 5,2L/100km (5%)
- 4,9L/100km vs 5.03L/100km (3%)

That is, averaged, 4,6% more than it actually is. Considering that at the pump, on average, they cheat, saying that you bought more fuel than what actually gets into the tank (how much on average, I don't know - I would guess 1-2% more) - I would say that the predictions of the Prius are quite accurate. I don't think other cars report fuel consumption any better than this.

[F8L]

Originally Posted by pakitt

That is, averaged, 4,6% more than it actually is. Considering that at the pump, on average, they cheat, saying that you bought more fuel than what actually gets into the tank (how much on average, I don't know - I would guess 1-2% more) - I would say that the predictions of the Prius are quite accurate. I don't think other cars report fuel consumption any better than this.

You did read the part about Toyota putting in a 6mpg offset on the first batch of cars and up to a 3mpg offset on later cars right?

Read post #5 again: 2010 Prius-III P&G, SHM and WS FE techniques rehashed, defined and refined - CleanMPG Forums

[CPSDarren]

3200 miles now. Computer has generally been 55-56 on every tank of 500 gallons. Actual has been 2-3mpg less than the computer.