What's new
By:
Ram Heavy Duty Forum

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

EVIC MPG Accuracy

CharlieL

CharlieL

Well-Known Member
Messages
255
Reaction score
375
Points
63
Location
Albuquerque
I operate on the assumption the EVIC MPG info is accurate; but only up to a given point. For instance, I really like the “instant mpg” and have that set to display in the lower right corner of the EVIC. Helps me to be more aware of what my right foot is doing! However, the average MPG shown in the EVIC is questionable as to what info it actually provides.

I’ve not reset the MPG shown in the "Fuel Economy" display in the EVIC, and it’s at 12.5. I’ve no doubt this is not accurate for the “lifetime mileage.” Based upon a post here, I started using the Road Trip LE app, and have input every gallon pumped and mile driven. It's very accurate (hand-checked to be sure) & it shows an average mpg of 15.85 over the 2,986 miles now on the truck. This includes an 1,100 mile highway drive home, 993 towing miles on a recent trip, and the rest is about 70/30 city/highway. From my experience with my 2013 1500, it seemed the EVIC MPG info is a rolling average based upon the last 250-300 or so miles. Seems to be about the same with the 2500. Curious what others of you might think &/or what your observations/opinions are.
 
Based on all calculations that I have done, my opinion is that the EVIC is a big fat liar.

And based on some exploring I did last week using some old school directions (1.8 miles to X, turn, go 10.4 miles, etc...) I am now of the suspicion that the odometer is also a liar, which could then mean the MPG figures are either further off than I previously thought, or a little bit closer to the truth. Either way, I will eventually do some calibration against a standalone GPS. More to ease my mind than to try and recalculate.
 
First thing to realize is that the "lifetime average" is not lifetime at all. Does not matter if you reset or not, it is a rolling chunk of time. Resetting at a fill up will ensure that the shown number is the most accurate and most recent, and deletes all data prior to the rest. But not resetting it does not equate to an average of say the last 5,000 miles (if you have 5K on it at that time), once the data set tables are filled/consumed, it begins to delete the oldest data and make space for the newest data to be logged.

Whatever it says even with a reset at each fill up, you can expect it to be showing around 0.75 to 1.5 MPG greater than what the true math will prove. They are always optimistic. If you see 12 MPG, you'll likely be around 11 in real life.
 
Consistently *at least* 1 mpg optimistic based on using Fuelly to track my mileage....
I basically ignore the EVIC (and DTE) and simply have an average in my head based on conditions as to how far I will get on a tank of gas.
 
the lifetime is not really a lifetime average it is like the last 500 miles or something like that. I figure every single tank full and the evic is usually optimistic by 1 or 2mpg but I have had times when it was very close. Usually on longer trips where I am driving 300-400 miles at a stretch between fillups it is more accurate than the running around town and shorter trips.
 
It sure seems like “lifetime” is actually way short, like half a tank (150-300 type of range). I’ve never reset mine and it still swings many multiple while numbers depending on towing and idling and low or high speed highway runs.

My Trip meter avg seems to favor 15ish. If my hand calc is about 15 it’s within about 0.5. If I get a good tank, it seems optimistic. If I get a low tank towing, it’s pessimistic. Like 2+ off from hand calc and further from 15 than actual.
 
Based on my hand calculations, my EVIC reads .3 mpg optimistic
 
Mine is about 1 mpg optimistic running empty and usually dead on or slightly low when towing.
 
I had 3 HD rams to date and the evic has always been optimistic on mpg by at least 10% seems like when compared to hand calcs.
No idea about the odometer accuracy, I would presume the feds would force them to be fairly accurate on this issue.
 
More often than not, my 2014 Ram 2500 was optimistic by 1 mpg compared to hand calcs.
 
My EVIC is anywhere from ~2-3mpg high right now. Started out around ~1.5mpg high when I first bought the truck (brand new purchase in 2016). I've hand calculated every fill up since new and never seen it closer then ~1.5 from hand calculated. I just subtract about 2.5mpg when I look at it to give me a rough idea what it really is

.
 
Lary0071 said:
First thing to realize is that the "lifetime average" is not lifetime at all. Does not matter if you reset or not, it is a rolling chunk of time. Resetting at a fill up will ensure that the shown number is the most accurate and most recent, and deletes all data prior to the rest. But not resetting it does not equate to an average of say the last 5,000 miles (if you have 5K on it at that time), once the data set tables are filled/consumed, it begins to delete the oldest data and make space for the newest data to be logged.

Whatever it says even with a reset at each fill up, you can expect it to be showing around 0.75 to 1.5 MPG greater than what the true math will prove. They are always optimistic. If you see 12 MPG, you'll likely be around 11 in real life.
Click to expand...

This.

I always reset it at each fill-up, and log my hand calculations into the Fuelly.com page on my smartphone quickly while I'm waiting. Then, Fuelly will give you awesome statistics over time including cost per mile, averages, etc. and it'll be accurate.
 
My evic is fairly accurate if my driving is consistent.. all freeway or all around town.. when I do alot of mixed driving it's way off..
 
Thanks to all for your input. I will follow the brilliant suggestion of resetting evic at each fillup and comparing to info from Road Trip app. I won’t create a log to track that info, though - that’s not me. What I’m most curious about is the mileage of the rolling average used. From past experience in my 1500 it seemed about 250 to 300.
 
CharlieL said:
Thanks to all for your input. I will follow the brilliant suggestion of resetting evic at each fillup and comparing to info from Road Trip app. I won’t create a log to track that info, though - that’s not me. What I’m most curious about is the mileage of the rolling average used. From past experience in my 1500 it seemed about 250 to 300.
Click to expand...
It's 200 Miles on the current generation
 
You must log in or register to reply here.
Back
Top