MT Fuel Economy Poll
 

Please select the option which corrosponds to the lifetime average fuel economy of your MT fits. You only get one vote. New car owners please refrain from voting until you get more than 3-5 tanks worth of data cuz one bad tank will mess up the stats.

i think 30-32 would be a close average for me.
lowest tank was 25mpg
highest was 40mpg

I've gotten as high as 36 mpg's and the low end is at 33 mpg's with all this done in normal city driving in my town.

High 35 MPG(us) (6.47L/100km)
Low 27 MPG(us) (8.76L/100km)

Mostly City Driving, not really agressive. About the same as what I got in my 80hp 1.9L Ford Escort.

I get between 34 and 36. But my lowest was 20... that was at the track though... everyone hated me :D

I'm going to hold off on voting since my milage keeps going up as the car breaks in (probably more importantly) warmer weather here in Minnesota.
My lowest tank was 28 80% city during a cold snap (-15F or so). My best tank was 38 on a road trip thru snow.

I just filled up and got 36.5 with 70% city driving taking it easy. Very happy so far.....

This is a good poll. A poll later in the year comprised of those who have carefully documented their OVERALL AVERAGE MPG FOR A YEAR would be even better.

I own a Dodge Caliber since 9/28/2006. My MPG began at an average of 30+MPG. The winter(with cold temps, shorter trips & lower energy winter mix gas) drove my MPG down to 28+MPG. However, with the warming weather & higher energy summer mix gas, my overall average for 39 tanks has rebounded to 30.9MPG & it continues to rise. My overall average MPG on 9/28/2007 will be my official overall average MPG considering weather MPG variations.

I believe that your website MPG poll would be more effective & accurate. However, I am impressed by the good performance of Fits in your present poll.

Lowest Ive had was 29mpg. Highest was 35mpg. Average I normally get per tank is 33-34mpg. All city driving and semi aggressive driving. I think since I did the hard break in my car gets better gas mileage when I rev her out a bit. If I try to rev low I get bad MPG.

Aftermarket wheels and a few mods. You should add if youre modded or not. It DOES matter.

A 5 min Overview of Process Analysis
 

Hi all,

I thought that I would share some knowledge with you. Here is the way process analysis works (which is what we are doing with the fuel mileage tracking).

In order to establish a "base line" there needs to be at least 25 observances (fillups). Depending on how far you drive this could take a year :(

Once you establish your base line, then you can determine your "mean average" by taking all 25 fill ups, adding them together, then dividing by 25.

Once you get your "mean average" established, then there is what's known as a "standard diviation" (plus and minus). This varies by the observations but as a ball park figure is roughly 1.5% of your mean average.

What this means is that if your average over 25 fillups is 29.7mpg, then the standard diviation is 1.6, your range for milage is then 28.1 to 31.3.

If you get a milage figure that is outside the norm, (like for instance 40 mpg or 15 mpg) you need to analyze why that happened. Once you have determine why (high tail wind, 3 hour idling time, etc.) then this observation is removed from your running observations.

Another quick note, if you discover 5 or more points going higher or lower, then this is pointing to a "trend" and it would be a good time to analyze what is causing it.

Hope this helps :)

<snipped out more statistical stuff>

I'm no statistical guru, but wouldn't the most accurate MPG numbers be given by simply adding up all of the miles you drove by all of the gas you put in? That would give you your ACTUAL lifetime MPG's.

Your method has you averaging the averages, which will give you an idea of the variances in individual measurements, but gives LESS accurate info on actual MPG's over the life of the car. This difference can be significant, especially if you fill up inconsistantly, e.g. sometimes with a near empty tank, and sometimes with a 1/2 full tank.

For example, using some made up numbrers:

Fill up and drive in mixed traffic till the E light comes on.
300 miles using 9 gals = 33.33 - ok so far

Now fill up and get in city traffic, fill up again after 100 miles
100 miles using 4 gallons = 25mpg

Whats your average?
True average = (300 + 100) / (9+4) = 30.76

Average of averages = (33.33 + 25) /2 = 29.16




<quote>
If you get a milage figure that is outside the norm, (like for instance 40 mpg or 15 mpg) you need to analyze why that happened. Once you have determine why (high tail wind, 3 hour idling time, etc.) then this observation is removed from your running observations.</quote>

Agree here, but I'd just remove this one measurement from your total and still calculate your 'true average' just leaving out this one measurement.

Easy to do in Excel. Just do a line item for each tank, but then calculate a lifetime average based on total gallons/total miles rather than averaging averages....

Thanks for your Input, some additional info.
 

"Your method has you averaging the averages, which will give you an idea of the variances in individual measurements, but gives LESS accurate info on actual MPG's over the life of the car."

You are right, we are doing an average of averages. By doing it this way we get a more accurate representation of what the actual mileage may be.

We also get an idea of what the high & low mpg's will be. Using Statistical Analysis will allow us to monitor trends in the mileage of the car over it's lifetime.

For instance, if we discover a lowering of mpg over a period of time we know that something has changed. Whether or not it is the type/grade/quality of fuel we are using, the season we are driving in, heavier traffic, or perhaps a problem with the car.

Granted, a lot of this information could wind up to be useless (what are you going to do about the quality of the fuel?)

Also the more observations (fill ups) you have, the closer it will come to your Total Miles/Total Gallons used method.

It's basically another way of playing with the numbers and not getting too upset if your mileage falls down to 30.2 from a previous fillup of 34.5!

I've included some make believe fillups just to generate some numbers, check them out if you want. I used Excell to figure out my Standard Diviation.


Fillup # miles gallons MPG Average StdDev UCL LCL Total of MPG
1 350 11.5 30.4 30.4
2 360 11.2 32.1 31.3 1.2 32.5 30.1 62.6
3 275 8.9 30.9 31.2 0.9 32.0 30.3 93.5
4 265 8.2 32.3 31.4 0.9 32.4 30.5 125.8
5 298 9 33.1 31.8 1.1 32.9 30.7 158.9
6 255 7.9 32.3 31.9 1.0 32.9 30.9 191.2
7 152 5 30.4 31.7 1.1 32.7 30.6 221.6
8 417 12.6 33.1 31.8 1.1 32.9 30.7 254.7
9 420 13 32.3 31.9 1.1 32.9 30.8 287.0
10 398 12 33.2 32.0 1.1 33.1 30.9 320.2
11 368 11.6 31.7 32.0 1.0 33.0 31.0 351.9
12 358 11.5 31.1 31.9 1.0 32.9 30.9 383.0
13 401 12 33.4 32.0 1.0 33.1 31.0 416.4
14 412 11.4 36.1 32.3 1.5 33.8 30.8 452.6
15 115 3.6 31.9 32.3 1.4 33.7 30.9 484.5
16 410 11.9 34.5 32.4 1.5 33.9 30.9 519.0
17 398 11.6 34.3 32.5 1.5 34.1 31.0 553.3
18 397 11.9 33.4 32.6 1.5 34.1 31.1 586.6
19 396 12 33.0 32.6 1.4 34.1 31.2 619.6
20 365 12.3 29.7 32.5 1.5 34.0 30.9 649.3
21 325 12.7 25.6 32.1 2.1 34.3 30.0 674.9
22 395 12.2 32.4 32.1 2.1 34.2 30.1 707.3
23 375 11.7 32.1 32.1 2.0 34.2 30.1 739.3
24 396 10.9 36.3 32.3 2.2 34.5 30.2 775.7
25 427 13 32.8 32.3 2.1 34.5 30.2 808.5
Total 8728 269.6 32.4 (Average of all miles driving divided by all gallons used)
UCL = Upper Control Limit
LCL = Lower Control Limit
Thanks for reading:)

Quote:

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You are right, we are doing an average of averages. By doing it this way we get a more accurate representation of what the actual mileage may be.

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Well, I'd say you get a better idea of what your expected range of milages could be, but your actual average is your actual average, and doing an average of averages won't give you that.

Quote:

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We also get an idea of what the high & low mpg's will be. Using Statistical Analysis will allow us to monitor trends in the mileage of the car over it's lifetime.
For instance, if we discover a lowering of mpg over a period of time we know that something has changed. Whether or not it is the type/grade/quality of fuel we are using, the season we are driving in, heavier traffic, or perhaps a problem with the car.

---

This is very true, and I think is the main advantage to using your method. Another way to do this is to track moving averages to smooth out any bumps in individual fillups, and let you see long term trends more easily. I use this here in Minnesota to track the effects of seasonal temperature changes, as we have a really wide range here ( about -25 to 100 F)

Quote:

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Also the more observations (fill ups) you have, the closer it will come to your Total Miles/Total Gallons used method.

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Agree 100% on this one.

I posted this before but a guy I talked to at the Honda dealer said he got 50+ mpg on a long road trip.

how can you check you MPG on the fit... when i use to have my pathfinder there was a switch that you press and show you the MPG...

I'm also a former Pathfinder owner! It was a 2006, great car, but the gas mileage just too crappy for today's prices. I miss the little MPG meter too. :(

Fill your tank completely, then reset one of the trip odometers (I use A).
At the next fillup, fill the tank completely again.
Get in the car, and divide the reading on the trip odometer by the number of gallons as it shows on your receipt.

i.e. You have gone 418 miles and it took 9.47 gallons to fill the tank to the starting point = 44.2 MPG.

If you don't fill the tank completely, you'll wind up with an amazing fuel economy number, followed by a terrible one at the next fill up, but it will average out.

Hello Storm8800, dear old CSi member.

And my fuel economy is currently averaging 41.56 MPG after 3385 miles. Best tank: 46.6, worst tank ever: 35.49 (3 people in the car, AC on, city traffic.)

Whats up Rich! Are you the guy from CS who spent $30k? :) :)

LMAO... no that was 137. Haha, only in cali.

Haha, that's crazy. You could get two base model Fits for that price around here! :D

ok, this is what I've noticed about my NHBP Fit. I now have over 4k miles on it and my fuel economy has changed due to the heavier/wider 17" wheels. :(

with stock wheels, I was getting as much as 45-47 mpg on highway, 32-35 mpg city/highway combined.

with the 17" wheels, I was getting a lower figure: 30-32 mpg highway, and as low as 23-25 mpg city.

I drive conservatively, no more than 60-65 mph, but there are times where aggresive accel. is a must for passing (maybe up to 5,500 rpm; normal accel. anywhere between 3,000-4,000 rpm).

in any case, I learned to deal with the fact that fuel economy was lost with the aftermarket wheels. it really is a lot heavier than stock (even by feel, without putting it on the scale). it looks good though :). I'd post a pic, but no camera at the moment.