Versa Real World Mileage against Trip Computer

[txchamps]

Would anybody care to compare notes about this subject? I'm keeping a spreadsheet log of my actual calculated mileage versus the computer mileage, sort of trying to get an idea if this is consistent across model years and trims.

If you are interested, please let us know the MY, trim, CVT, auto, or manual, etc. Also some notes about the type of driving (city vs. hwy) and your general driving habits -- NO JUDGMENTS!

I just got a Versa Note 5 speed manual three weeks ago. Had the first fillup after 2 weeks. The trip computer consistently hovered around 39 MPG, which I knew had to be wrong. Starting with a full tank, I drove 335 miles, 20% city and the rest freeway, and put 9.617 gals in , so the mileage came out to 34.83, a little over 4 MPG differential. I'll keep updating to see if anything changes. I'm pretty happy with the mileage though. I do my best to minimize undue acceleration and idling, and I am soft on my cars as a general rule. People don't generally like driving behind me

Happy driving, everybody!

[docswitzer]

Pretty much the same with my 2014 Versa Note SL, with the CVT. The trip odometer definitely reads higher than reality, with a 3-4 MPG difference at every fill-up. I too keep a spreadsheet, so after 8k miles the actual best to date is 35.54mpg (mostly highway), and the worst is 29.52mpg (mostly city). I only wonder if the entire odometer system is skewed or if it's just the trip odometer. Speedometer matches my GPS, but I haven't compared GPS mileage to the vehicle odometer yet. Will observe over the next few days.

It definitely affects my MPG the more I am on the throttle, sitting in traffic, wind resistance, time at red lights, etcetera. Overall, it's a great little car so far.

[txchamps]

I only wonder if the entire odometer system is skewed or if it's just the trip odometer. Speedometer matches my GPS, but I haven't compared GPS mileage to the vehicle odometer yet. Will observe over the next few days.

I don't think you have to worry about that. The odometer system and the average MPG estimater use different data sources. At worst the odometer has an influence on the MPG thingie, but not vice verse, to the best of my knowedge.

[txchamps]

Second fill-up on my Versa Note 5 speed manual:

Traveled 341 miles, pumped in 9.63 gallons, for mpg of 35.41, a slight improvement over the previous 34.83. Trip computer once again estimated 39 mpg, for difference of 3.59 as opposed to first reading which was 4.19 mpgs off. Not too shabby, sez I to nnobody in particular. If this is consistent, I can rely on it to be 3 to 4 miles off and use it as a pretty good guide. We shall see.

Forgot to add that driving was mixed, with mostly freeway, just as before -- probably an extra city trip or two of about three miles each.

[txchamps]

3rd fill-up today in my Versa note 5-speed manual.

Travelled 335 miles, pumped 8.979 gallons, for MPG of 37.31, the best yet. Trip meter MPG ended up at 40.4, reducing the difference to 3.09, another decline. Don't know whether that means anything. Average fuel consumption overall is 35.82 MPG.

Driving pattern was a bit different, as it included a short 100 mile round trip in the hill country, as well as a couple of in-city custumer service visits, and a cross-town delivery. I also changed a significant driving habit, learned from perusing this forum. I had a habit of coasting to stops in neutral, thinking that this saved gas. However I learned that coasting in gear is more economical, as the injectors shut off as soon as the accelerator pedal is released above 1500 RPMs. (they them kick back in below 1500 to keep the engine from stalling). Thanks to AZhitman for this helpful and interesting tidbit.

[MrWiggles]

Just wondering; how fast do you go on the highway? I tend to stay at around 75-80mph and mostly drive highway but seem to always get around 33-35 mpg max. Hoping I can figure out how to squeeze a little more out of it if I can.

[txchamps]

Just wondering; how fast do you go on the highway? I tend to stay at around 75-80mph and mostly drive highway but seem to always get around 33-35 mpg max. Hoping I can figure out how to squeeze a little more out of it if I can.

I very rarely go over 70. I try to keep my RPMs in the 3000 to 3300 range or less. You may have read that I learned that it was more economical to coast in gear than in neutral. Seems that when you release the accelerator above 1500 RPM while in gear, the injectors shut down. If you're coasting in neutral, they're squirting fuel the whole time, same as idling. Cool thing to know. So now I coast in gear whenever possible.

I'm easy on acceleration, shifting as low as I dare without lugging it. Travel in 5th gear if I'm going 35 MPH or faster. That's about it. It helps to turn off the ignition if you have a long light to wait for, but I never do it. I'm no hyper-miler. Just a boring old fart driver trying to save a buck.

[MrWiggles]

Thanks for the reply! I started shifting at much higher rpms, but as I get more comfortable with the car I have learned I can easily shift at lower rpms without worry. I keep the car in gear until the last second, so I'm good there. I wonder if the main difference for me is how I drive on the highway. I may have to test this out after the next fill up.

[txchamps]

Thanks for the reply! I started shifting at much higher rpms, but as I get more comfortable with the car I have learned I can easily shift at lower rpms without worry. I keep the car in gear until the last second, so I'm good there. I wonder if the main difference for me is how I drive on the highway. I may have to test this out after the next fill up.

I think you can pretty much count on it. This article, a little heavy on the math, pretty much says it all. Ignore the math and just look at the graph set out at the bottom of the page. The effect of speed on MPG is significant.

http://www.wired.com/2011/04/what-will- ... r-mileage/

This is why I don't break 70MPH very often.

Happy driving!

[txchamps]

Instead of a long narrative, this time I will simply post a snap of my spreadsheet. Driving details: More stop and go and idling (construction going on near home) and two cross-town deliveries, so city driving about 25% during the latest cycle. Difference between real world and computer hovering right around 4 MPG.

I would certainly like to see some other members' experiences, if you have the data and care to share.

[docswitzer]

I only wonder if the entire odometer system is skewed or if it's just the trip odometer. Speedometer matches my GPS, but I haven't compared GPS mileage to the vehicle odometer yet. Will observe over the next few days.

I don't think you have to worry about that. The odometer system and the average MPG estimater use different data sources. At worst the odometer has an influence on the MPG thingie, but not vice verse, to the best of my knowedge.

I figured that the trip odo had to be fed from the main odo. Confirmed with my GPS. Guess it's just isolated to the computer MPG. Biggest MPG killer is the 15% loss of efficiency with ethanol. Rated @ 40 x .85 = 34, so I am spot on. Still love the car! Thanks!

[txchamps]

The way I understand it is the that the mileage computer uses an algorithm based on data from the MAF sensor and the fuel tank level sensor, among other things. The odom and the trip odom are indeed directly linked. I believe that the mileage computer is deliberately calibrated to be, shall we say, optimistic. I am thinking that it will be more accurate on long road trips, but way off if the majority of driving is in stop and go and urban settings. I don't have the data to back that theory up as yet.

If you are doing a spreadsheet, or have tracked a lot of your fill-ups, I would love to see the data, esp. compared to the computer's numbers.

[txchamps]

Latest fill up:



Notes on driving -- during the latest period, I deliberately drove more aggressively. I revved higher, took corners faster, and exceeded 70 MPH in freeway driving. Mix still pretty much 15/85, but there has been a lot of stop and go because of construction on freeway. So perhaps figure it more like 20/80. The results, not surprisingly, were a reduction by about 1 MPG. I have stopped trying to find logic or regularity in the computer's mileage. I want to see how it reads on an extended road trip, though. Might have to wait until spring, when I plan to run up to Denver.

[txchamps]

Latest fill-up:



The most interesting factor right now is the price of gas -- the bottom appears to be falling out of the market. How low can it go before they turn around and shaft us once again?

My driving habits reverted back to my conservative style, but a cold snap has worked against me, as well as a bit more in-city driving and continued construction on the freeway -- lots of stop and go. So I'll say the mix is 25-75, although I don't have exact figures. Too much of a pain to keep those kinds of records. Suffice it to say my commuting time to get home has risen from 25 minutes to 35. A real pain especially with manual trans.

[txchamps]

Latest fill-up. 25% intensive in-city driving taking trips to and from Hospital (everything is okay). Lots of idling and stop and go. Mileage suffered as you can see

[PostItNote]

I have consistently observed at least a 10% optimistic Trip Computer Calculated MPG vs. Actual, over my first 5000 miles of use.

[txchamps]

Whatever it is, it is not consistent. I am interested to see its behavior on a long trip. Also am considering not resetting it with each fill-up and see how it measures up to my cumulative mileage. With today's technology, one would think that they could come up with something a bit more accurate.

[txchamps]

Haven't updated this in a while. some oddities to point out:

12/31 fill-up followed a trip to Austin and back, 180 miles -- 3 people up, two people down, with a lengthy urban trip, no freeway, in the middle. Disappointing results, I was execting something more along the lines of 37 to 38 MPG. Too big a load, too fast, too much idling in the city.

1/25/15 fill-up is an anomaly. Gas pump was malfuntioning and would only dribble gas into the tank. Kept shutting off. The place was jammed so couldn't change pumps, subsequently, filled the tank to the brim, rather than my usual practice of giving it one more squirt after the first shut-off. Notice the wide swing in difference between calculated and computer MPG. This affected the next fill-up as well -- so those two are outliers. Bottom line is that the car still gets a remarkably consistent 35 MPG overall.

Clipped off the Feb 28 fill-up. I'll add that in next post.

[txchamps]

For those of you who are interested (probably damn few) here is the updated spreadsheet:



The last fill-up reflects another round-trip to Austin, this time heavily loaded with 4 individuals -- 2 large and 2 medium. I will add that this affected the car's handling as well. I do not recommend overloading a Versa Note. I must have been carrying 800 lbs. worth of people and luggage.

Whew.

[txchamps]

Welp,

The name of this thread has become irrelevant, because it has become apparent that the trip computer's mileage bears no identifiable relationship to real world mileage, as you can easily see from the graph. They are close, and there ios a general directional similarity, but as an indicator of probable mileage on any given trip, it is useless. Just too many variables, I guess.

But keeping close tabs on mileage in general has been interesting. The most interesting thing is this sudden uptrend since I had my first service on March 3. I attribute it to that, as well as the warmer weather, the completion of construction along my main route to and from work, and the end of the "break-in" period. If it continues, I'll post it. If not, this thread will be over and I will start looking at other, more interesting things to share.

Thanks for indulging me in my MPG fetish

[kevinrs]

I think this is due to how it is calculated. The instantaneous MPG may be pretty accurate, but it's sampled based on time, and then the average is calculated from that.
To match with actual miles driven, it would have to be sampled based on using a set volume of gas.
When you are idling at low RPM for 10 seconds, you are using a small amount of gas, and moving 0 miles, getting 0 mpg for 10 seconds added to the average when idling at higher RPM for 10 seconds, you are using more gas, but adding the same 0 mpg for 10 seconds to the average, without regard for how much gas was used.
This, and other errors based on the time based sampling add up to make the average mpg less accurate. It actually might be accurate if you drove at the same rpm and speed for an extended period of time between fillups, with no stops at all, but otherwise, due to the way it's measured, the "average" is not very useful.
Not really anything that can be done about it, it's just something we've got to be aware of.

[txchamps]

Exactly. I am looking forward to a long road trip in late August (not just to see how this works -- I'm going to see my first grandbaby!).

Also, There are so many variables with each fill-up, that I am beginning to think that the trip computer might be closer to real mileage than I am giving it credit for. We shall see,

Thanks for your input!