3 months of fuel economy statistics for MT V6 TRD OR. BS will be destroyed.

Damnit... I forgot I have to long press the button for 5 seconds to completely disengage.

 

Again, you drive an Automatic Transmission so not really relevant here.

 

"I bought this truck/money pit for the fuel economy" - Nobody

 

I actually did buy mine because it is supposed to get around 12.8 l/100 km for my city/highway mix, and that was better than the F-150 I was cross-shopping. That was not the biggest or only reason, but it was a factor for sure.

I have not gone through one full tank yet, but so far the truck is saying 15.8 l/100 km. I hope to God that is because it is -30 C here, my gas is full of ethanol, and there is a lot of friction loss because the engine is new. I have been short shifting to keep revs under 3500, which I thought would improve fuel economy, but it doesn't seem to have that effect.

 

So trolling this guys post is a better use of time?
I actually appreciate the time you spent analyzing the data you collected on your truck. As a person who spends a great deal of time collecting and analyzing data in my profession, I realize that this type of analysis is not very time consuming and the people bashing it spend more time a day on this forum than it ever took to do that in excel.

 

I use the same method the The Fast Lane Truck uses. I filled until the pump stops and then I wait 30 seconds and fill the tank until the pump stop again.


My input data is not accurate to millionth of a MPG. Everything is based on pump displays and the dash display. If there are more than two decimal points, it was an output of an excel function.


I don't have strong science background, and I only use excel for FP&A and Accounting. I managed to avoid any difficult science classes in college (only took Geology), but I did take intro to statistics, Econometrics, and up-to Calculus III. I don't remember any talk about significant digits.

I know, the usual response is, "Just google it". However, if you are able to help me improve my methods and accuracy, please! if you are able to take some time to help me, I would really appreciate it.

 

That's definitely true, but it's not the fun way.

 

Well stated, BatmanOK.

The OP did a pretty good job of describing the topic in the title of the thread. Not sure why anyone would take the time to read (much less comment) if they're disinterested.

 

This is why I like Fuelly.

 

You have committed no great crime, and people who feel the need to point out that they have an engineering degree usually have "issues." It is easy to criticize people like you who actually try to make meaningful contributions, and it doesn't reflect well on the critic.

The basic complaint is that if you are reporting the amount of fuel you are putting in the tank to two decimal places, you are claiming that the pump can measure to about 3.8 ml, you have the exact same insertion depth on the nozzle every time, the fuel cutoff works the same way every time, your odometer is really accurate (say to 0.01 mi), and the temperature correction on the pump can be relied on. If you just round all those mpg numbers to one decimal place, that will satisfy 90% of the concerns.

 

a universal question about human nature, actually not just limited to humans. lol

 

I love nerd projects*, so I hope I didn't sound like I was trying to slam you.

One suggestion to increase accuracy, it looks like you're using the vehicle odometer for the miles you drive in a tank of gas, which is to the single miles digit. Doesn't the trip odometer go to the tenth of a mile? I'd use that instead. The trip odometer calc might result in say 349 miles on a tank... but that could actually be 349.9 or 349.0, basically almost a mile off.

I'm still struggling on the accuracy of the volume of gas for each fillup. I just don't trust that the fuel pumps all auto stop at the same point. The best way would be to run the tank dry, then fill up with the exact same volume every time. but that's crazy talk.

For data presentation, plot the vehicle mpg on a tank versus the matched calculated one for the same fillup. Then put a one-to-one line on the plot (a line from bottom left to top right). If most of the data falls on one side or the other of that one-to-one line, then you can see a bias (it's basically a visual ratio). You could also show the R2 value (it's a setting in the trend line options). Crossplots are great. Alternatively, take the ratio of vehicle to calculated mpg for each tank of gas, then plot those on a time scale, maybe there's a seasonal error in the displayed mpg.

My intuition is that you still have a small sample size.

---------------
* my greatest useless nerd project was I wanted to see the actual time my daughter's bus arrived, and figure out exactly when I should leave our house to get to the bus stop. So I set up a program to be able to speak "Bus arrived" into my android wear watch, then have that time upload into a google doc spreadsheet (there was some steps in between), and then update an average arrival time in a spreadsheet so then I could see my daughter's bus which was supposed to arrive at 8:25 actually got to our bus stop on average at 8:37. So I avoided 10 minutes of standing at the bus stop for nothing.

 

I broke 20mpg and got close a few times, and I am currently sitting at a 19.7 tank average.

What I do is this:

For city driving:

In first and second gear, I go to 3-4 RPM max, but after that, I go straight to 4th or even 5th depending my my speed. I try to never exceed 1.5 RPM in city driving. Don't lug the engine though. Drop to the appropriate gear and rev match if you need to accelerate.

Additionally, keep the Current MPG meter (the horizontal blue bar) on your driver's dash right below the digital MPH gauge. This setup has helped me to understand how this engine operates. I think...

When entering low load and even low load conditions at high RPM, the current MPG meter will double or sometimes triple or quadruple almost instantly. Especially, when you let off the gas and then slightly depress to maintain speed. It will go from 5 MPG to 20 or 30 MPG. I have taken this to mean that the engine switched to the atkinson cycle. Once you get a feel for this, you can almost control when the engine goes into Atkinson Cycle.

For highway driving:

Just drive slower, and try to keep the engine in the Atkinson Cylce as much as possible. I don't understand why people need to drive at 80-90 MPH at all times. Their are so many driving deaths. If you have tonno cover, driving up to 75MPG on flat ground will keep your car operating at 20-22 MPG

For stop-in-go traffic:

This is a nightmare situation for Manual Trannies. if you are doing this everyday, then try to really control your foot. The best I can do in stop-n-go is 15MPG. I have found that 10-14MPG is quite Normal.

 

I guess my hopes and dreams are dashed upon the rocks once again.

 

Definitely feeling the damn winter gas here.

 

Another suggestion... what is the average MPG before and after the tonneau cover installation. excel has a t-test function and maybe be able to determine if there's a statistically significant increase in MPG by adding the cover. Again, my intuition is too little data though to make the test meaningful.

And for s's and g's, I did a quick trend analysis (Mann Kendall Trend Analysis), and converse to what the trend line suggests, your calculated MPG trend is increasing (mk score = 23). I just did this quick in excel, and can't assign a statistical significance to the result, so take it with a grain of salt. But it's possible that you have been driving more consciously aware of MPGs compared to when you first started tallying your data.

 

This is an important variable here. My daily highway commute is somewhat hilly. Not big hills, but still many ups and downs, which drastically affects my gas mileage. Below is the elevation change of my morning commute (evening commute is the opposite). The highway portion of my commute begins at mile 4.5 and ends at mile 18 on the chart. The first 4.5 miles are at 45 MPH while the highway portion is typically 65-70 MPH.

My gas mileage is much better in the morning than in the evening due to the overall elevation change. Additionally, on a windy day I would typically be driving into the wind on the trip home. There have been a few very windy days where I've averaged around 22 MPG on the way to work and 15 MPG on the way home. Overall, I've seen a lifetime (11k miles so far) average of 17.4 MPG. Taking into account my 265/70R17 tire size, I think that brings me to about 18 MPG.

 

Mix of winter fuel and engine is less fuel efficient in winters---the dash computer says i get around 14-15mpg with city driving. Quite a bit of stop and go so thats pretty much what I expect. I drive less than 10 miles to work each day so it doesn't bother me at all.

 

There are V6 MTs that average well over 20 mpg on fuelly. They get tanks over 24 occasionally.

I see you have a radar detector... mystery solved.