MPG VS MPH

kjansen said:

A little off the topic, but pulling my big 5er I will average 11.5 to 11.8.  A couple of weeks ago I pulled a smaller trailer with my JD Gator on it and only got .5 mpg better mileage.  That really surprised me due to the weight difference and wind drag.

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Assuming the gator trailer has a significantly smaller frontal area......
so I'd guess that there are other variables in play.... headwind, number of stop lights, time waiting at stoplights, hills, dragging brake on the trailer, etc...
I honestly wouldn't think it would be much different than that, but 12mpg compared with 11.8mpg isn't much....

Okay - I read all the posts and to appease everyone's scientific processes I drove my 2017 Chevy Bolt EV on a circle track in one direction on a day which began at 70*, had no temperature change all day with a constant wind of 3 mph.  I filled my tank with as much gas as it would take and it took the exact same amount every time.  I drove the track at exactly 70 mph the first trip, 65 mph the second trip, 60 mph the third trip and 55 mph the last trip.  I used exactly the same amount of gas on every trip, so it seems as much or more regarding mpg is directly related to the vehicle and less to the environment.

Have fun with that. 

Tom:  My test had nothing to do with filling a fuel tank accurately.  As Brad said in his posts, I used the system built into the truck that calculates mpg based on computer measured fuel consumption and distance traveled.  It covered the SAME ROADS, mostly interstates where both lanes follow the same path at the same elevation.  Elevation of the two end points is within 100 feet.  It is true you can show 99 mpg by this method for VERY SHORT distances, but this was 150 miles.  It was not posted to start an argument, but to demonstrate the value to fuel consumption of small speed reductions.  A fun post.  Just remember, YMMV!  (Your Mileage May Vary)

ClickHill,

You posted while I typed.  You make an excellent point!

I could claim the same thing if I changed the word "FUEL" to "GAS"  ;D

Grashly,

This was a GREAT post!! I laughed at every reply after your original post.  Too fun.

Regarding concrete being smoother than asphalt, definitely not where I live, unless the asphalt road is 10-15 years old and is ready to be resurfaced.  The concrete roads here have very deep grooves in them when new while asphalt, at least for 5 or so years, is smooth as glass.  It does certainly degrade faster than concrete but when comparing new to new, the asphalt here is much smoother.

I will say in the snow/ice you get much less traction on the new asphalt (we call them blacktop roads here) compared to concrete.

Now, if you are talking about roads that have been seal coated (tar then pea gravel applied), I agree, concrete is much smother than that.

Years ago our local Chevy dealer was part of a competition GM put on testing mileage of a Monte Carlo (rear wheel drive, mid 80's I think).  All vehicles were identical trim/options (yes, I know the build tolerances between the cars varies and can affect mileage  8)).  I think there were about 15 or 20 cars in the test to see what driver could get the best mileage.

I believe the winner averaged in the low 50 mph range, which surprised me.  I would have thought just getting the transmission in the highest gear at the lowest speed would have been the best.

Okay - I read all the posts and to appease everyone's scientific processes I drove my 2017 Chevy Bolt EV on a circle track in one direction on a day which began at 70*, had no temperature change all day with a constant wind of 3 mph.  I filled my tank with as much gas as it would take and it took the exact same amount every time.  I drove the track at exactly 70 mph the first trip, 65 mph the second trip, 60 mph the third trip and 55 mph the last trip.  I used exactly the same amount of gas on every trip, so it seems as much or more regarding mpg is directly related to the vehicle and less to the environment.

Have fun with that. 

Wise guy 

Click Hill, now I suppose you're going to tell us you did it all in first gear too 

HappyWanderer said:

Reset it at the end top of a long hill, watch the average soar to 99 MPG. Then take a photo to impress gullible friends!

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Yeah. I love letting off the pedal on a downhill stretch and watch the instant MPG peg out the meter.

I remember one day driving across Texas headed East.. Most all day the Average MPG was hanging in just shy of 14 MPG (13.8 for most of the day) except when the computer did it's reset and the Average went off the chart.. I truly was getting nearly 14MPG,, no cheat, No fake, NO timing the photo I was getting nearly 14 MPG.. but the reason was that "Drag increas as the square of the speed" 

I had no wind drag.. I had wind PUSH (Weather report said abou 100 MPH coming from DEAD astern and I mean even the Tumble weerds, which were passing me like I had the brakes on,, were going straignt down the road).

John From Detroit said:

I remember one day driving across Texas headed East.. Most all day the Average MPG was hanging in just shy of 14 MPG (13.8 for most of the day) except when the computer did it's reset and the Average went off the chart.. I truly was getting nearly 14MPG,, no cheat, No fake, NO timing the photo I was getting nearly 14 MPG.. but the reason was that "Drag increas as the square of the speed" 

I had no wind drag.. I had wind PUSH (Weather report said abou 100 MPH coming from DEAD astern and I mean even the Tumble weerds, which were passing me like I had the brakes on,, were going straignt down the road).

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You are lucky some times the wind blows hard.
Bill

WILDEBILL308 said:

You are lucky some times the wind blows hard.
Bill

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No kidding.  In '16 we stopped at Lake Meredith up near Borger.  My wife opened the door to the coach and the wind caught it so fast she didn't have time to let go of it.  Pulled her right out of the coach and onto the ground.  I was already relaxing at the picnic table and it was all over before I could move. 
She ended up with a complete shoulder replacement out of that deal.
So, yes, the wind in Texas is nothing to be sneezed at.

Had a similar experience crossing Nebraska one day. The wind was strong and directly behind, and the mpg climbed to 11-12 from the normal 8.1 when cruising an interstate. It was a most pleasant surprise!

Gary RV_Wizard said:

Had a similar experience crossing Nebraska one day. The wind was strong and directly behind, and the mpg climbed to 11-12 from the normal 8.1 when cruising an interstate. It was a most pleasant surprise!

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Maybe we should start following the wind when traveling .

Rene T said:

Maybe we should start following the wind when traveling .

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I agree but it seems I am always going into the wind and the sun.  I guess I am always going the wrong direction.  Need to get the wife to change our travels plans.

Rene T said:

Maybe we should start following the wind when traveling .

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Well, with "prevailing westerlies"...

for what it's worth.....

my '03 F250 PSD 7.3 has the onboard computer.  Bought it new, and I've kept track of every mile and every gallon of fuel.  In ~175K miles, I can honestly say that the computer's calculation of MPG is nothing but a pipe dream.....I sure WISH it were accurate!

No modifications BTW, other than secondary oil filtration....

I have found that 2000 RPM (68-70 MPH depending on conditions) is the "sweet spot".  Anything over that substantially reduces mileage.

I can't wait to put some miles on my new to me rig, it's got a Ford 460 with the Banks Turbo power kit......to see how many GPM I use.   
But heck, after getting 1.5 - 1.75 MPG in my boat, I'm sure it'll be an improvement!

I will get better mileage on 2 lane country roads at 50-60 MPH compared to freeway 65-68 MPG.

I for one use my fuel as quickly as I can because I don't want t going bad, there fore the nickname.

butchiiii said:

Okay - I read all the posts and to appease everyone's scientific processes I drove my 2017 Chevy Bolt EV on a circle track in one direction on a day which began at 70*, had no temperature change all day with a constant wind of 3 mph.  I filled my tank with as much gas as it would take and it took the exact same amount every time.  I drove the track at exactly 70 mph the first trip, 65 mph the second trip, 60 mph the third trip and 55 mph the last trip.  I used exactly the same amount of gas on every trip, so it seems as much or more regarding mpg is directly related to the vehicle and less to the environment.

Have fun with that. 

Wise guy 

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Yeah, I heard that them Bolts get great gas mileage. I rented one for my last trip to KC for work. I made it all the way to KC without having to stop for gas.
Did still have to stop for Coffee refills a couple of times, though.