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OK, I'm watching my mpgs routinely on the 08' xb just like i do on my other vehicles. I never had the benefit of an on-board computer to calculate the mpgs for me in the past, so i always hand-calculate them anyway.
I've notice that sometimes the xb computer and hand-calc come out the same, but sometimes they will be apart by about 2 - 3 mpg. Average mpg is average mpg........what gives?:(

BTW, the last couple of highway trips on relatively flat roads, the xb has churned out 31 mpg consistently. I'm staying just under 70 mph to get that but still not bad for this car loaded with gear and a couple of bikes on a rack in the back. I expected to loose a couple mpgs with the bikes, but nope, didn't happen. :D
 

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OK, I'm watching my mpgs routinely on the 08' xb just like i do on my other vehicles. I never had the benefit of an on-board computer to calculate the mpgs for me in the past, so i always hand-calculate them anyway.
I've notice that sometimes the xb computer and hand-calc come out the same, but sometimes they will be apart by about 2 - 3 mpg. Average mpg is average mpg........what gives?:(

BTW, the last couple of highway trips on relatively flat roads, the xb has churned out 31 mpg consistently. I'm staying just under 70 mph to get that but still not bad for this car loaded with gear and a couple of bikes on a rack in the back. I expected to loose a couple mpgs with the bikes, but nope, didn't happen. :D
Maybe the difference is when you are sitting still idling in traffic or at a red light...?
 

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i avg anywhere from 28-31 depending how i drive and terrain...
 

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yeah... I thought it would be more accurate but it takes into account the stops... Takes time to learn after a reset... and just seems to be wrong most of the time. I watched it go down while I was at a stop light. Hand calculating is the only way to know for sure. Even my scangauge is all over the charts compared to the trip computer.:eek:
 

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my reasoning tells me that the problem with the dash computer is that it is too accurate. the reason it displays a higher average is because when you see --.- in the display it is not recording data even tho you are burning fuel. it only records data when the vehicle is adding miles to the odometer. the same holds true for hand calculations. you could fill up, let your vehicle idle overnight until it runs out of gas and your precise, hand calculations wont mean a thing. that is the very reason you get better mpg on the highway, there is less unrecorded spent fuel. the dash computer is a very useful tool in learning better driving habits that lead to better fuel consumption.
 

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my reasoning tells me that the problem with the dash computer is that it is too accurate. the reason it displays a higher average is because when you see --.- in the display it is not recording data even tho you are burning fuel. it only records data when the vehicle is adding miles to the odometer. the same holds true for hand calculations. you could fill up, let your vehicle idle overnight until it runs out of gas and your precise, hand calculations wont mean a thing. that is the very reason you get better mpg on the highway, there is less unrecorded spent fuel. the dash computer is a very useful tool in learning better driving habits that lead to better fuel consumption.
I have seen the mpg go down while at a light idling, making me believe that the comp. does in fact take idle/stop into the equation.
 

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my reasoning tells me that the problem with the dash computer is that it is too accurate. the reason it displays a higher average is because when you see --.- in the display it is not recording data even tho you are burning fuel. it only records data when the vehicle is adding miles to the odometer. the same holds true for hand calculations. you could fill up, let your vehicle idle overnight until it runs out of gas and your precise, hand calculations wont mean a thing. that is the very reason you get better mpg on the highway, there is less unrecorded spent fuel. the dash computer is a very useful tool in learning better driving habits that lead to better fuel consumption.
Guess it depends on what you're trying to measure. I want to know how much it actually costs for me to go however many miles in real life. Wishful thinking life doesn't mean a whole lot to me. Given I don't have any highway miles, but I do have stop lights and traffic slow downs, I might as well know what I'm actually dealing with -- the rosy view just isn't that helpful (and I've no evidence to verify the rosy view is even accurate for non-stop optimal gearing/slope situations :(!) Don't get me wrong, I'm not complaining about the car, but as far as I'm concerned, hand-calculated is king -- that's reality!
 

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The popular/fun answer is that the onboard trip computer of course lies, and only "admits" to whatever it says, 18MPG in city driving in my case.

A better answer is probably that filling the tank up is less than accurate, that when the pump clicks full it's not quite full, and not quite filled up to the same amount every time. They say topping off the tank is bad for the hydraulics, anyway, right?

Cars.com falls into the latter camp trusting the on-board trip computer.

Anyway, I do agree that watching the average MPG in the trip computer is a great tool for learning to hypermile. I find the instant MPG readout useless; it's just an "inverse throttle guage," as one YouTube video puts it.
 

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I've never reset mine and it hovers around 24.0 lowest 23.6 and highest 24.3. Almost 8k miles. Shrug.

Still double what I used to get in my old truck, I'll take it.

I babied it when new but now that it's broken in I occasionally romp on it when the mood strikes or traffic warrants it.
 

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The popular/fun answer is that the onboard trip computer of course lies, and only "admits" to whatever it says, 18MPG in city driving in my case.

A better answer is probably that filling the tank up is less than accurate, that when the pump clicks full it's not quite full, and not quite filled up to the same amount every time.
What does it matter whether the tank is actually full following "filling"? The question is how many miles elapse from one "fill" to the next. The average number is your hand measured MPG.
They say topping off the tank is bad for the hydraulics, anyway, right?

Cars.com falls into the latter camp trusting the on-board trip computer.

Anyway, I do agree that watching the average MPG in the trip computer is a great tool for learning to hypermile. I find the instant MPG readout useless; it's just an "inverse throttle guage," as one YouTube video puts it.
The tank should absolutely not be topped off in light of risk of overflowing into the charcoal evaporation tank. But what has that to do with hydraulics or other rational factors?
 

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Gday all.

Im going to throw a spanner in the works, cause i dont know MPG.

My Rukus i have on a lease through work, my computer is saying 8.9L/100kms, and has from day one. Yet my monthly lease statement is saying 9.5L/100kms

I generaly get between 500-540kms and it takes 45-48L to fill up so going on my limited maths ability the computer is close but not spot on.

Great forum, found it couple of weeks ago and bean drooling over the cars since
 

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First, welcome to the forum. I'm sure you've read about the scare we in the states had with the price of gas, some predicting it could get to $5.00 a gal.this summer. What are you paying for a liter of petrol?
 

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What does it matter whether the tank is actually full following "filling"? The question is how many miles elapse from one "fill" to the next. The average number is your hand measured MPG.
according to that article JC posted, the difference is in the pumps, they could be off as much as a half gallon from when one shuts off compared to where the next pumps shuts off when "full". so if you are putting in an extra half gallon (or quart) you aren't getting an accurate reading. sure your equation will still equate but your result will vary because of that fluctuation.
 

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Another thing that hasnt been mentioned is that the quality of gas is different at each station. Here in Oregon we have 10% ethanol and anyone who has a boat knows that ethanol sucks up water and gives sh*t milage and jacks up the fuel system.
So if you live in a damp climate and the station has old gas it will be filled with (10%?) water + ethanol. I have been getting variations of 18 mpg in town to 23 mpg in town following the same traffic patterns but with different gas stations... There is one that is more expensive (Shell) that has very low traffic compared to a cheaper (busier) station 1 block down the road (Chevron). I get a constant 4-5 mpg better at the high turnover station... I blame ethanol. There is a station 20 miles away that sells "race gas" with 0% ethanol I put in my high compression Air-cooled VW but it is 5 bux a gallon...:eek:
 
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