Trip Computer MPG

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2016.5 CX-5 GT AWD titanium/black 2016 Miata Club ST MT white
A lot of people calculate manually because it is so ridiculously easy nowadays.
This app:
https://play.google.com/store/apps/details?id=com.kajda.fuelio

has been installed over million times. And there are many others.
And here's one for the Apple heads:
https://apps.apple.com/us/app/fuelly-mpg-service-tracker/id295905460



1995 called bro and wants you to get an app. Some of them synch to your PC or let you download it all if you want. Notebooks?!?
;)
I called 'em back and told them to forget the app. I also told 1995 that I'll bet a LOT of people these days don't even know how to divide the number of miles driven by the number of gallons used to calculate their fuel economy.

Don't you fret though, I'm no luddite. I'm no stranger to tech and I use lots of apps for other things, just not tracking my fuel economy.
 

7eregrine

The man, the myth, the legend
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Land of Cleve
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2016.5 CX5
I called 'em back and told them to forget the app.
:D

I also told 1995 that I'll bet a LOT of people these days don't even know how to divide the number of miles driven by the number of gallons used to calculate their fuel economy.
Yea, but it's easy to figure it out, so I bet it's more common then you think: "Hey Google. How do I calculate MPG?" lol
 
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2016.5 CX-5 GT AWD titanium/black 2016 Miata Club ST MT white
:D


Yea, but it's easy to figure it out, so I bet it's more common then you think: "Hey Google. How do I calculate MPG?" lol
That's very true, ask Google. I'd ask Alexa though, if I didn't know how. (yes)

My point is that, in my opinion, not many could figure it out themselves. Let's see miles PER gallon, miles/gallon. How do I calculate that! (thumb)
 
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2019 Mazda CX-5 Signature
For those manually logging & computing your MPG, are you doing it per tankful or computing a longer-term average? I feel you need to average it over a longer period of time for accuracy. And I'd guess (but haven't looked it up) the Mazda computer keeps a running average until it is manually reset.

Regardless, you can't compare the two numbers unless you use the same methodology.

But what I really want to know is how many of you have run until the tank is empty just to see how accurate the trip computer's "miles-remaining" calculation is.
(cabpatch)
That's what I look at on a long trip.
 
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2018 CX-9 Sig
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2014 CX-5 GT
I calculate it and keep a record in Fuelly. My CX-5 was always equal to the computer when calculated over 2 tanks. My CX-9 computer is always 0.4-0.6 MPG higher than the calculated.
 
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Mazda CX 5 Touring
you're kidding right! You get upset that the computer is off a couple of miles per gallon? Put a piece of electrical tape over the display and forget about it. They provide you with something like this and you get upset? What would you do if you didn't have power windows, air conditioning, or power seats. This thing gets better mileage than my 1966 40HP VW bug that I had to push start until I fixed the starter. Be Happy!!!!!!!!!!!!!!
 

Avoidin Deer

Zoom Zoom, baby
Contributor
:
Central Virginia
:
2019 CX-5 Reserve
For those manually logging & computing your MPG, are you doing it per tankful or computing a longer-term average? I feel you need to average it over a longer period of time for accuracy. And I'd guess (but haven't looked it up) the Mazda computer keeps a running average until it is manually reset.

Regardless, you can't compare the two numbers unless you use the same methodology.

But what I really want to know is how many of you have run until the tank is empty just to see how accurate the trip computer's "miles-remaining" calculation is.
(cabpatch)
That's what I look at on a long trip.
I do it per tankful, and keep a running record of it:


Here are the fields:
Date: Date I filled up
Station: Brand/Location purchased of the just-consumed tank
Octane: Octane of the just-consumed (93 is highlighted)
Miles: Miles driven on the just-consumed tank (Trip A, gets reset every tank)
#Gals: Number of gallons at this fill up
Calc: Manual MPG calculation of the just-consumed tank
Comp: Computer's MPG of the just-consumed tank (Trip A, gets reset every tank)
Calc vs Comp: Calculated MPG vs Computer MPG, in actual MPG and as a % of the Computer's MPG
To Match Comp: #Gals/cups of gas more/less required for Calc MPG to equal Comp MPG for that fillup
---I did this so I could see how likely it is that large MPG differences were due to not topping off properly at the tank Start/End, and so I could track this to account for MPG differences from tank-to-tank.

The first line is the tank the Dealer provided. It is not included in my calcs because I have no idea if it truly was a full tank.

At the aggregate (about 4,400 miles), the Average Calculated MPG is .55 MPG higher than Average Computer MPG.

Need I say it? YMMV ;)
 
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7eregrine

The man, the myth, the legend
:
Land of Cleve
:
2016.5 CX5
you're kidding right! You get upset that the computer is off a couple of miles per gallon? Put a piece of electrical tape over the display and forget about it. They provide you with something like this and you get upset? What would you do if you didn't have power windows, air conditioning, or power seats. This thing gets better mileage than my 1966 40HP VW bug that I had to push start until I fixed the starter. Be Happy!!!!!!!!!!!!!!
Ohhhh, I like this guy! And totally agree. Y'know the one thing I didn't give AF about when I bought my car? MPG. ;)
 
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2007 3i & 2014 CX-5
I bought mine last October and I had to check tank-to-tank because the trip computer was showing anywhere from 33.5mpg to 34.1mpg. I was highly skeptical that this bubble butt little SUV is getting that kind of gas mileage. I still can hardly believe it, but it actually is! Tracking by tank, it's always been within +/- 1mpg.
 

Avoidin Deer

Zoom Zoom, baby
Contributor
:
Central Virginia
:
2019 CX-5 Reserve
are you guys resetting the mpg counter (not just the trip meter) at each refill?
Mine are one in the same.

I have a Trip A and a Trip B. Both have their Miles and MPG counters. I let Trip B keep on running, and reset Trip A at every fill up.

Miles get set to 0.
MPG gets set to 0 as well.
You can't reset just one.
 

Chocolate

Harpy Eagle
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2019 CX-5 AWD
How many people calculate their true MPG by hand and compare it to the trip computer?

My trip computer ALWAYS grossly overestimates the MPG I'm getting. It's usually not even close to the actual MPG.

I drove 412 miles on my last tank...
- Trip computer said 35.0 MPG.
- Actual gas mileage was 32.5 MPG. It overstated the fuel economy by 2.5 MPG!

That has been the most egregious overstatement, though it is almost always off by 1.5 - 2.0 MPG.

My guess is the Mazda engineers (correctly) assume most owners do not check their mileage by hand.
So they can program the trip computer to state wildly optimistic MPG numbers, and consumers will be none the wiser.
They are far from the only ones to overstate MPG on the trip computer. This is exactly why you calculate it by hand, gasoline is measured to the thousandths of a gallon. It's simple enough to grab a pic or write down your odometer at 1 fillup and then at the next.
 

Chocolate

Harpy Eagle
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2019 CX-5 AWD
One thing to note since there are a lot of Canadians on the forum, the U.S. measures fuel in gallons and Canada measures in liters. If the US was metric, our fuel prices would be much higher. Good for your wallet, bad for the environment.
 
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