Very low MPG across two states (38-40 MPG)

The roof rack will definitely impact the mileage, as will the high speeds and cross/head winds. Still, I think your numbers are awfully awfully low.

 

In my experience, people almost always ignore speed limits to go faster...not slower. That is why I mentioned it. It was very odd to see nearly everyone going slower than the 80MPH freeway limit.

 

Noticed the same thing here, in zones with limits recently raised to 110~120 kms: a lot of drivers evidently saying "screw this, I'm going a bit slower, thank you".

 

And I remember my wife driving a 400 ci, Plymouth Fury wagon trying to use the 'mph' speed for the posted 'kph' signs . . . certainly kept me awake!

Bob Wilson

 

But ignoring the signs means, by definition, just driving the speed one darn well pleases, with no regard to whether the signs show a higher or lower number. "Ignoring" means paying no heed at all to the signs, one way or the other. That's what I think you saw.

 

Hmm...I also think some people have a hard time 'ignoring' the need to post a useless response...sigh...

 

Comparing the equivalent time periods:

• before rack: 5 below 45 MPG 29%, 12 above 45 MPGm 71%
  
• after rack: 6 below 45 MPG 54%, 5 above 45 MPG 46%

Bob Wilson

 

Interestingly, one time I drove through Missouri I too had very low gas mileage:

Code:

Date         Miles     Gal        MPG    MP Tank
6/26/2015    33638    4.191    52.73    627.51    GA -> NE
6/27/2015    34091    9.092    49.82    592.91 
6/28/2015    34425    9.464    35.29    419.97    Casey's Store #2888 in Higginsville, MO
6/28/2015    34759    8.087    41.30    491.48 
7/03/2015    35110    7.640    45.94    546.71    NE -> GA
7/06/2015    35360    5.328    46.92    558.37 
7/07/2015    35781    9.548    44.09    524.71 
7/07/2015    36168    8.412    46.01    547.47  

My speed was more-or-less the same in both directions (mostly interstate, so about 75 mph). Throwing out this one outlier, I average 46.3 MPG under regular driving conditions and 46.7 on the highway. Thus I suspect the pump in Higgensville cheated me... in fact, if they dispensed 0.8 gal for every 1 gal I was charged, that would take my MPG back up to 41.

Sure, it could be weather or the hills or something, but this is the only anomalous reading in my MPG record.

 

"Casey's Store #2888 in Higginsville, MO"

• Your route was along the Ozark plateau with numerous altitude changes
• On that day, the local airport reported gusty, head-quartering winds
• The temperatures were in the mid-80s so the AC was turned on
  • More so because you were driving into the sun, making cabin hotter

You were actually traveling faster than 75 mph:

Bob Wilson

 

I drove prius from Houston Texas to Los Angeles, I averaged 43 MPG, two children, two children car seats, two adults(driver & passenger), snacks, and luggage. What I noticed big negative fuel impact was driving through the hills and average 78 MPH. I would go insane if I had to drive 55-65 MPH, I have patience but no patience to drive 65 MPH for long period of time..

 

Not bad It took me 11 years and 140,000 miles to get my first Subaru significantly above its EPA rating. That was a surprise because the prior Accord was easily beating its EPA Highway from the very first tank.

Though I should admit that the effort lagged until gasoline jumped to $4.50 / gallon, pushing me to try much harder.

 

Something to keep in mind is that in some of those regions, you might have gotten a tank of E10-87 as well which would only make your MPG worse - if you previously filled up with regular 87 octane the mpg hit would be noticeable afterwards.

Anyway, my point is if all driving conditions stay the same and you get a tankful of E10 your mileage will take a hit afterward. Anything else (such as crosswinds, temperature, hills, etc) will just add to it.

 

That is what lowered mine down. Used to get 100% gas at SAMs club then they switched to E10. Plus after the recall on power inverter. Not to mention that Oklahoma is always windy. That kills the mpg to around 35

 

Hey just like to point out that the gas in Missouri and Montana us usually drop my mpg in any of my vehicles... so if you do trips through them try to get the bare minimum gas from them

SM-N920V ?

 

I normally do better in Montana than down here at sea level, due to the higher elevation and thinner air.

But you are in an even higher place, so your results will be poorer almost anywhere else you travel.