Hi gang. Ok for all you slide rule nuts and engineers out there, see if this can be explained: We left Denver Friday for a fun filled week out west. From Denver to St.George UT I ave. 31.5 MPG at 73.15 MPH. Using 92 octane gas. From St George to LA the ave was 24.3 MPG at 53.5 MPH. Using 91 octane gas. I filled last night 91 octane, cleared the mpg computer, have driven in LA no different than Denver, and the computer is estimating 20 MPG. In Denver, my computer est is 27.6 MPG. Any ideas why this is so? I will be touching in this week, as we make our way up northa and then east.

 

I was driving from Oklahoma to Vegas in a killer windstorm that was blowing right at me at ~50mph. My mileage was 21 mpg. Usually it is around 30 mpg with the way I drive. One day I was taking a forty mile round trip and decided to drive super mellow and only 60 mph. My mileage was 38 mpg. Going through mountains makes a big difference too, especially if your destination is at a higher elevation.

There are many things that affect mileage, these are just a few.

John

 

I think David that your MINI, like a lot of the country, has an irrational hatred of California. You need to have a talk with her and show her the error in her ways.

Have a safe trip. I've reserved a two-page spread in the June MINI5280 newsletter just for your adventures.

 

I believe the stated mpg ratings are done at 55mph, no wind, straight road, on a full moon night & no spouse / passenger.

Just kidding on the full moon, but if the ocean tide moves 10 feet due to Lunar pull, what would a light weight Mini do if driven "only 60 mph. My mileage was 38 mpg" - during a moon light ride? Now that would be harnessing alternative energy!

Thought #2: From St George to LA the ave was 24.3 MPG at 53.5 MPH. Using 91 octane gas. Was this actually a twisty road w/ 20 mph curves, you were averaging 53.5, Nancy squeezing her "Oh S---" panic bar on the passenger door again? Perhaps a choke hold twisty road meter by the Mrs. = poor fuel economy.....

 

David,
Here's how to confirm your MPG. Put black electrical tape over your MINI's computer readout. When you fill the gas tank, jot down the odometer mileage. Do your driving. When you fill up again, jot down the gallons put in and the odometer reading. When you get home, do the math. That is your MPG. The computer is just a snapshot in time (even the "average" reading) and not truly representative of your trip, whether it's to Aurora or to LA.

But, if your really want to be scientific about it. Hook up your laptop computer to the MINI's OBD-II port (with adapter) and plot and record all the engine paramaters necessary for computing MPG as you drive. Then, you'll see that it's a curvey, wavey line that goes up and down all the time (even the average does). I have all the gear. Let's do that some time. And we could hook up a video camera too.
--Rick

 

Do your own math.
It's the only accurate way.

 

Ok. We are finally back in Colorado. Rick, I did not need to electric tape/computer hookup. Excel works wonders. For starters, on every fillup, I recorded on my gas receipt the following data: Trip odo reading, Computer mpg, computer mph. using this data, I created a spreadsheet with the following: Day; Mileage(from my trip Odo, reset every fillup);Gallons used; MPG comp. MPG actual ( Mileage/Gallons used);Ave Speed(from the computer); Total$; $/Gal. Here is the totals: Mileage: 3258.8; Gal used:118.924; MPG computer:30.41; MPG Actual: 29.35; Ave speed 56.44286 mph; Total $: $304.83; Ave $/gal: $2.52. So the computer is very close to actual. I-15 s. from St George is straight and pretty level until the Virgin River Gorge. I was in a pretty good headwind. I was able to hit 40 mpg(computer) from Laramie to Arvada yesterday. Off to unpacking and laundry.

 

Don't forget to add the "fun" factor to your computations...