l/100km error

[walter592]

My new gen3 car is displaying a full 10% error in the calculated vs real l/100km gas mileage. I'm on my 5th gas tank now and it's pretty consistent. This is even higher that the US error of about 5%, anyone else experiencing this? I wonder if the EPA estimates are on this error as i'm not getting anywhere near the 3.8/4.0 while my previous car I could easily beat the EPA estimates.

[Radon]

The EPA is based on flat road driving and for a set distance. In a normal none hybrid car matching the EPA up and down hills and for short trips is a bit easier as you have no hybrid system that needs to kick in. With the Prius during warmup the engine runs till the computer decideds it is at the tempurature for the best economy. This means for short trips you will be moving with the engine running rather than in hybrid mode.

Also, as I noted for myself, I live at the top of a very long hill which means the engine must run constantly to get me up to the top. I get 5.2 - 5.4 l / 100km on my day to day going to and from work (10 min drive basically down the huge hill in the AM and up the huge hill in the PM). My Smart car couldn't keep to its EPA data on that commute either although my Thunderbird which consumes far more fuel did.

I've done a few longer trips which I've managed 2.8/100km over a 50ish km distance on highway and flatter roads.

[fuzzy1]

... I wonder if the EPA estimates are on this error as i'm not getting anywhere near the 3.8/4.0 while my previous car I could easily beat the EPA estimates.

The EPA test cycle does not use the car's displayed MPG at all. It uses the same measurements on this car that it uses on cars with no MPG display.

My Prius is beating its EPA numbers by a significantly smaller margin than any of my pre-hybrids, and even they beat it by much different margins.

[Spartane]

Originally Posted by walter592

My new gen3 car is displaying a full 10% error in the calculated vs real l/100km gas mileage. I'm on my 5th gas tank now and it's pretty consistent. This is even higher that the US error of about 5%, anyone else experiencing this? I wonder if the EPA estimates are on this error as i'm not getting anywhere near the 3.8/4.0 while my previous car I could easily beat the EPA estimates.

Yeah, the 10% error sounds about right to me (it might actually be a bit over 10%).

My car's display says 3.4L/100km, but it measures 3.8L/100km when I fill it up at the gas pump (very consistent mileage). My work commute is about 53km in each direction, an hour of mostly rush-hour stop-and-go highway driving across the top of Toronto on the 403/401/404 highways.

I put about 38 liters in it and drive nine days with about 1000 km between fill-ups.

[Tideland Prius]

Crap... i'm getting 4.1L/100km. That means I'm closer to 4.5L/100km?

[Spartane]

Originally Posted by Tideland Prius

Crap... i'm getting 4.1L/100km. That means I'm closer to 4.5L/100km?

4.4 - 4.5 would be my guess.

Please let us know!

[moner]

Originally Posted by Tideland Prius

Crap... i'm getting 4.1L/100km. That means I'm closer to 4.5L/100km?

My car's display and the consumption I've calculated through Fuelly are still showing the same over the last 4000km, 4.9L/100km. Can't see any error on mine yet, strange others are seeing such a difference.

[Tideland Prius]

I will but I'm still on the dealer tank. I'll let you know at the end of Sept when I drive down. That'll take one tank for sure.

[Richard P]

I noticed the same with my car and I started a thread on that some weeks ago and "Philosophe" suggested me to see on this thread ;

2010 calculated vs. computer MPG - Please post your results

So it seems to be quite a frequent problem. Oddly, the computer always lower the consumption !!!???

[Airbalancer]

Tom River NJ to Gananoque ON 670km, 30.55 l , at the gas station, cal 4.56 l/100km. OBE 4.4l/100km, that was driving 110
They had attensents at noth station filling the gas
I was amazed at the mileage
Really you do not know how much fuel you put in the car?
How much is left in the hose?
Close is good in horse shoe and the mileage game