Jump to content
LegacyGT.com

Lifetime gas mileage calculation


Recommended Posts

I was focusing in the wrong context, what you are saying is true. sorry for going off on you for that.

 

wasn't disputing the physics and science behind it all, was just speculative of the magnitude of the effects at speeds higher than the tested 50-55 mph. some calculations show me that the loads are less than 200 lbf at 100 mph, that shouldn't be a lot for a 175 hp drive train to overcome.

 

that graph you posted, seems to be generic ? i'd be interested in seeing the losses from drivetrain/aero/etc. specifically for this model ... if such data is available online.

Link to comment
Share on other sites

  • 2 weeks later...
  • Replies 138
  • Created
  • Last Reply
my latest fillup was yest. nothing out of the ordinary as far as driving habit and trips -- except that temps dropped into the upper 40's to mid 50's and i used remote start once. my tank average came out to 26. previous fillup tank average was 31.
Link to comment
Share on other sites

If I push the odometer reset button on a fill up does that re-set the mpg as well?

 

For that odometer yes. I reset B every time I fill up to compare what the car calculates to Fuelly. I got the car with 10 miles on it and the odometer A reset. I have never reset it as I use it for lifetime mpg average.

 

If you click the button quickly it switches between A and B, push and hold and it resets whichever one you're on.

Link to comment
Share on other sites

thats what i do also ... it zeros out the trip mpg, not lifetime.

 

i reset lifetime about 5k ago and it seems to be reading normal ... i have to cross check it with the data i accumulated for mpgs since that point ....

 

so far the trip counter has been between 1 and 2 mpg off from what i measure at the pump

Link to comment
Share on other sites

Okay, just finished the year: 5757 miles, 217.3 gallons = 26.5 mpg overall. It's disappointing. I'd expected much better, given that in previous bought-new vehicles (mostly Honda/Acura, but including a 2000 Subaru Outback with a manny tranny) I've averaged fairly close to the EPA highway mileage shown for that vehicle.

 

The problem seems to be the CVT transmission, which causes the engine to turn over much faster in cold weather -- and in New Hampshire, cold weather is much of the time. Here in the southern part of the state, we are also afflicted with a 10 percent ethanol mix, and the EPA of course does its testing with unadulterated gasoline.

 

My best mileage was in July, at 31.2 mpg.

 

The worst was in January, at 22.7 mpg.

 

Almost all my traveling is on country roads at with little traffic at speeds between 30 mph and 70 mph. I have a light foot, and I have been driving these same roads for over 30 years -- generally with better gas mileage than I get from Subie. (2015 Legacy 2.5i, bought new last October.)

Link to comment
Share on other sites

in about 2 months im coming up on my 1 year with this car so ill post then. put it all in a fancy spreadsheet so i can get graphs to look at as well ...

my mileage will be about 5 times more than what you put on. i know my all time low was 20mpg.

looking at lifetime so far my car registers at about 26.5, which includes about 70% highway driving.

some put the blame on speeds higher than 55, others put the blame on other factors that try to hint that the car is being driven non-optimally ...

anyway ... i do agree with you that there is something going on, because i also observe better results with other makes.

not sure how this will play out in the bigger picture as many ppl start wondering y they spend so much on fuel when the mpg ratings give a guesstimate thats indicates otherwise.

Link to comment
Share on other sites

I've had the car 14 months now and just shy of 17k miles. I usually drive with a lead foot and do a lot of city driving.

 

I'm at 22.1 mpg average over the lifetime of the car. On the few long freeway trips I've done, I've averaged almost 30mpg (and I'm usually doing 75-80mph) which is better than epa rating. I do my calculations off gas used and miles, not what the car says. It always reads 1.5-2 mpg higher.

 

Yeah, 22mpg sucks, but it beats the 17 I was getting and paying for premium fuel in the BMW. Sometimes I wish I got the four banger but the only car on the lot with heated rear seats was the 3.6R.

 

With that said, my next car will be another BMW because Subaru doesn't make a hardtop convertible.

Link to comment
Share on other sites

While I have had my loaner for about 2 weeks now and have put about 800 miles on it, I have noticed something odd about how the head unit and the cluster behave in regards to how they display average and instant mileage

 

Head unit is overly optimistic showing average of 34 mpg while the cluster shows average of 29.4 which is in line with what my manual calculations show

 

The head unit also samples at a much slower rate than the cluster does

 

IMHO I would trust the cluster over the head unit

Link to comment
Share on other sites

I've had the 2.5i engine and the fuel economy set in l/100 km so I was out of the loop on the mpg - it is formally possible to convert but why bother. But I decided to switch the display to mpg and mph and see what happens since I was going to be crossing the border. I was surprised to see that the mpg meter was steady at 38 to 39 (that is the cumulative one, not the instantaneous one) on a highway trip. I find that more impressive than getting below 6 l/100 km for no good reason. Now that I've seen the mpg numbers and I'm back home in metric land I realize how remarkable this car is. And the dealer replaced the hinge on the gas filler door so all is well.
Link to comment
Share on other sites

  • 3 weeks later...

ive given my legacy to my wife a week ago for her to drive. she works 1 mile from our house.

the current trip reading (since the last fillup) says 25 mpg so far and its used about 1/2 tank.

ironically, ive been driving my old 2002 m3 to work, ive gone thru 1 tank/trip already and the pump mpg i measured was 22.

my route and traffic is the same as before.

so this 13 year old car with 133k miles on it gave me 22 mpg. its rating is 17/24 (epa estimate).

and i was a bit lead footed ... my highway speeds were between 75-90, with many bursts of acceleration ....

bmw is conservative, subaru is sloppy.

Link to comment
Share on other sites

@zero7404 been wining about his gas mileage since day one while most people are basically satisfied.

 

 

 

10 months to the day:

21000 miles, 26.7 mpg, $ 1650 spent on fuel.

more than i anticipated.

 

well hey, 1.5 mpg variation isn't all too bad for an onboard computer.

 

and regarding the 20 mpg observed ... i'd rather drive an Explorer it would give me the same mpg and its much bigger than the Legacy - some kind of side by side comparison for ppl to realize how incredibly inefficient the 6th gen Legacy can be.

 

 

i reset my lifetime mpg when i did my oil recently ...

so far i filled up twice and the average trip (i set it per tank) has read out about 31-32 mpg. lifetime says 32. my calculated since i reset it has been 31 and change ... so it seems the eco monitor is accurate so far. but eventually the lifetime will start straying upward if i dont reset it

 

 

my driving habbit hasnt changed over the past 2 fillups but the mpg has jumped to 31-32. i think outside temp has something to do with it because i noticed when its really hot out the mpg goes down a little. it was also really crappy during the winter.

thats my opinion. i think the ecu is programmed such that max mpg is delivered by the engine for a narrow set of conditions.

the rest of the time it drinks too much fuel or the cvt isnt functioning optimally to deliver better numbers

 

 

This enough,..,......,......

Laughing at Oneself and with Other is good for the Soul😆
Link to comment
Share on other sites

no im not. since you havent been following my posts, it may indeed sound silly if u just read that one post.

i have a detailed record with receipts for 11 months worth of driving the car starting from odometer reading 6 miles.

i will post everything i have in this thread next month when i close 1 full year with this car.

Link to comment
Share on other sites

@zero7404 been wining about his gas mileage since day one while most people are basically satisfied.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This enough,..,......,......

 

 

why are you bothering with this thread ? i can talk about this subject in here. you're not satisfied in the discussion then you go somewhere else.

 

dont tell me to shut up buddy.

Link to comment
Share on other sites

why are you bothering with this thread ? i can talk about this subject in here. you're not satisfied in the discussion then you go somewhere else.

 

dont tell me to shut up buddy.

"Enough" was the reference that I got tired of going through all the old post and had nothing to do with your ability to complain. You taking it personal please don't.

 

Feel free to express yourself because I am a strong defender of the 1st, 2nd, and 4nd Amendment.

 

I would be the last person which would to hender your right to express yourself. The only exception I have with any of your statements was "Class Action Lawsuit" which is my prerogative, beside that, go for it. I do want to add from prior threads and even a 2.5i poll the results did not agree with your assessment.

Laughing at Oneself and with Other is good for the Soul😆
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.




×
×
  • Create New...

Important Information

Terms of Use