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ByDesign · 12-20-2015, 11:06 AM

I really appreciate all that everyone has posted here. Great thoughts and education!

Here's a wrap-up for the year. I'm done with the expos for a few months, so thought I'd post a synopsis.

The truck usually gets something between 14.7 and 15.1 MPG on the highway. Stinks, but gets me there -- and for that matter -- anywhere I've ever wanted to go in sun, rain, deep snow, mud, ice, wind, sand, back hills, high-clearance washouts, high mountains, 4-wheel-drive trails, etc..

That being said I've used 14.8 MPG as the baseline for the truck, and 12.6 MPG as the baseline for comparison with the trailer (pulling the trailer without modification -- Trip #1). 12.6 MPG (or minus 2.2 MPG) is a 15% hit for pulling the trailer. With the gap filler, 13.3 MPG, or minus 1.5 MPG is a 9% drop from normal. That means, having the gap filled yields a 5% improvement (roughly, for these simple one-off tests).

Slowing down 10 or so mph yielded about the same savings as adding the gap filler. Again, keep in mind that these are one-off tests with uncontrolled variables (like wind), so don't take this too deep. A good portion of the slower test improvement could just be staying out of the enrichment scheduling on the engine map. Interesting, none the less.

In dollars and cents, that means, for one of my expo trips (~200 miles give or take), the savings with the gap filler or the slower speed is less than 1 gallon of gas. 3 or 4 times a month that doesn't pay for much time or material in mods -- it doesn't even pay for my time to go a little slower! -- which is actually a pretty depressing thought.

More trips with variations like hitch height and speed have yielded basically the same results as above. The best econ achieved was 13.8 MPG for a 210 mile trip on snow and ice so the speeds were low, but rolling resistance higher. So many factors, most of which are not controllable.

It might seem a little silly, but I love the learning, even if the results are hard to distinguish sometimes. Thanks for all the comments and thoughts. I've got some time now and loads of ideas (thanks to you), so we'll see what comes in the spring.

12-20-2015, 11:06 AM	#55 (permalink)
ByDesign Eco Dabbler Join Date: Oct 2015 Location: Colorado Posts: 45 Thanks: 33 Thanked 33 Times in 19 Posts	I really appreciate all that everyone has posted here. Great thoughts and education! Here's a wrap-up for the year. I'm done with the expos for a few months, so thought I'd post a synopsis. The truck usually gets something between 14.7 and 15.1 MPG on the highway. Stinks, but gets me there -- and for that matter -- anywhere I've ever wanted to go in sun, rain, deep snow, mud, ice, wind, sand, back hills, high-clearance washouts, high mountains, 4-wheel-drive trails, etc.. That being said I've used 14.8 MPG as the baseline for the truck, and 12.6 MPG as the baseline for comparison with the trailer (pulling the trailer without modification -- Trip #1). 12.6 MPG (or minus 2.2 MPG) is a 15% hit for pulling the trailer. With the gap filler, 13.3 MPG, or minus 1.5 MPG is a 9% drop from normal. That means, having the gap filled yields a 5% improvement (roughly, for these simple one-off tests). Slowing down 10 or so mph yielded about the same savings as adding the gap filler. Again, keep in mind that these are one-off tests with uncontrolled variables (like wind), so don't take this too deep. A good portion of the slower test improvement could just be staying out of the enrichment scheduling on the engine map. Interesting, none the less. In dollars and cents, that means, for one of my expo trips (~200 miles give or take), the savings with the gap filler or the slower speed is less than 1 gallon of gas. 3 or 4 times a month that doesn't pay for much time or material in mods -- it doesn't even pay for my time to go a little slower! -- which is actually a pretty depressing thought. More trips with variations like hitch height and speed have yielded basically the same results as above. The best econ achieved was 13.8 MPG for a 210 mile trip on snow and ice so the speeds were low, but rolling resistance higher. So many factors, most of which are not controllable. It might seem a little silly, but I love the learning, even if the results are hard to distinguish sometimes. Thanks for all the comments and thoughts. I've got some time now and loads of ideas (thanks to you), so we'll see what comes in the spring.