Gas mileage ?

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Re: Gas mileage ?

Postby KCStudly » Tue Nov 17, 2015 4:50 pm

You will probably see an increase over the next 20,000. My Escape gained about 3 mpg once it was broken in.
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Re: Gas mileage ?

Postby daveesl77 » Tue Nov 17, 2015 8:15 pm

My 2004 F150 5.4 triton gets 17-18mpg normal mileage on the highway at about 65. Pulling the trailer reduced this down by about 1 mpg (16-17). My old pop-up, slidein truck camper knocked it down to about 14mgh. Pulling my 25' Coachmen at 55 mph put it down to about 12mpg. All were way better than my old 34' Bounder, which got 4-6mpg (454 gas) and drove like a billboard.


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Re: Gas mileage ?

Postby Cliffmeister2000 » Wed Nov 18, 2015 12:56 am

Those electronic gas mileage things in the newer vehicles are notoriously optimistic. My 2014 Durango with 8 speed tranny gets 2-3 mpg less in reality than the gauge says I'm getting. Still, I'm happy with the unloaded 30mpg I get in a 7 passenger vehicle.
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Re: Gas mileage ?

Postby deceiver » Wed Nov 18, 2015 6:39 am

Cliffmeister2000 wrote:Those electronic gas mileage things in the newer vehicles are notoriously optimistic. My 2014 Durango with 8 speed tranny gets 2-3 mpg less in reality than the gauge says I'm getting. Still, I'm happy with the unloaded 30mpg I get in a 7 passenger vehicle.



I'll have to check it with some actual math. I was just happy to feel a noticable longer ride from a tank of gas than my 2003 silverado.
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Re: Gas mileage ?

Postby Steve33455 » Thu Jan 14, 2016 8:20 pm

vax wrote:I average about 21-23mpg in my 2000 toyota tacoma on the highway, when I'm towing my trailer (cargo conversion not tear drop but its got the nose cone) I get around 18-20 depending on grade. all in all I cant complain, except that a bigger truck would more power would be nice = ]
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Re: Gas mileage ?

Postby Adirondackersouth » Tue Jan 19, 2016 7:10 pm

Hello I am new, not gnu that's a horse of a different kind. :R

I read every entry on the thread and I wanted to add my hopeful comment and add something else to the mix. My summer camping excursions run between 3-5000 miles and I do this in a Toyota Highlander without a Teardrop or Tiny Travel Trailer. I mean I load up my vehicle with a kayak, canoe, camping gear, telescope sometimes, cooler, tarps underwater filming equipment, fishing tackle, hiking gear, cooking, clothes and sundry other items. Since I travel alone I can fill every available space and my fuel economy does not change one iota loaded or empty that I can tell. Maybe I lose a mpg here or there but its not noticeable enough to note. I get 23-24 up and down mountains in the East from VA to Maine and back to VA.

If I add a teardrop that weighs 1200-1300 lbs and leave it essentially empty and keeping most of the gear in my vehicle would that be just adding another 1300 lbs of weight and thereby reducing fuel economy?

Or

Would it be no difference if I stowed the majority of my gear in the teardrop and called it a day.

Does this kind of micropacking count for anything?
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Re: Gas mileage ?

Postby KCStudly » Tue Jan 19, 2016 7:37 pm

If you are doing mostly highway driving with few stops and starts, hauling a heavier load inside of the vehicle won't necessarily show up as much as loading things onto a roof rack (including the rack itself) or towing them in a trailer. The roof mounted stuff and trailer adds to the aerodynamic drag all of the time at speed, whereas the extra weight more or less just needs more energy to get moving, or to climb.

In my Ford Escape I saw about 1 to 1-1/2 mpg gain just by switching from high test to 87 octane; I mostly operate very close to sea level.
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Re: Gas mileage ?

Postby daveesl77 » Tue Jan 19, 2016 7:42 pm

Well, since we downsized from the F150 to the Kia Sedona, did a test trip and got 23 mpg, an increase of 6 mpg or 33% over the truck. I like it! Towed very, very easily.

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Re: Gas mileage ?

Postby pchast » Tue Jan 19, 2016 10:22 pm

Adirondackersouth

If your new TD is (smaller) within the shadow of your SUV you are
unlikely to see much difference in the gas mileage. With my '15 Frontier,
4cyl 2wd, I get 19 at 70mph unloaded. When I add the TD, with no cap to
streamline things, I get almost 16 at 70mph. That s about 20% cost. For
comparison its about 30% drop when using my wife's VW with a smaller
turbo engine and a TD a foot higher than the car top.
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Re:

Postby Adirondackersouth » Tue Mar 01, 2016 9:50 pm

slowcowboy wrote:on my ford explore on a 800 mile trip to rifle colorado and back to pavillon, wyoming I noticed no drop at all in gas milage towing my teardrop.

No lack of power and I towed 65 mph even up hills. I out ran larger motor homes and bumper pull rvs. same rigs known on here as ttt or standys.

I ran with no sway problems 65 in hard wind in wyoming and down around rifle last labor day.

I out ran my buddy towing a large boat with the same explore his is a 94 mine is a 95.

I make this trip to colorado every labor day and I go almost every year.

I have driven it with the same 95 ford explore about 5 to 6 times.

I got the same gas milage towing my teardrop last year as I got with out it the years before.

Slowcowboy.


Hey Slowcowboy -

The debate in my head and the conversations I have had since exploring the whole concept of long haul teardrop travel has me feeling a bit vexed on several levels. :roll:

For starters I have a Toyota Highlander with 143K. I have ordered a hitch and ball that should be in soon. I can, or I think I can install it myself according to those who do these kinds of things and of course YouTube is a good instructor of many things. So once that is done, the next challenge is should I beef up the cooler and brakes or leave well enough alone. My goal is not to haul cattle or cement in my trailer of choice, and where I will be traveling it will be a lot of stop and go traffic for a good stretch then highway then back to start and stop. Some off road and some extended camping or bunking with friends and relatives maybe. I am not the guy currently to hit the high passes of the West, but there may come a day when I start heading West, so your encouragement does give me hope. I had a 2000 Ranger XLT that would have hauled with impunity, the SUV I now have is rated at 2K, not 4K as was the truck. I get 24 mpg unloaded and about 24 mpg loaded with camping, fishing gear with two boats on the roof. One kayak and one old canoe rides on top with a combined weight of 160 lbs. Again the Highlander did very well last summer when I tripped North. Adding a trailer of 1000 lbs is substantial wight but not bad enough to worry too much. Again that is why my attention has been focused on Teardrops. 8)

The other big question is finding one in my price range which has been a challenge and a half. But I think I can do it before June. I hope anyway.

Any suggestions? Know anyone in the Richmond, Virginia area that has one to sell?

Cheers :frustrated:
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Re: Gas mileage ?

Postby Redneck Teepee » Tue Mar 01, 2016 11:59 pm

My experience with fuel mileage while towing my teardrop has always been a wash or increase. Its well known that when you start pushing above 55 mph your mileage starts to take a hit, when not towing I'll push to 70 mph more often than not on the highways.
The speed limit in Kalifornia for towing is 55mph and I pretty much stick to the speed limit. I set it on cruise control 55-58 mph depending on traffic flow, when your on teardrop time you should not be in a hurry anyway. :D
I tow with both a V8 gas hot rod pickup, and a Duramax diesel pickup which I know also makes a big difference in available power/torque. Weighing in at about 1400 lbs neither one knows it's even behind it.
Cruise control and 55 mph are your best friends, it keeps the CHP busy with other people and improves mileage. :thumbsup:
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Re: Gas mileage ?

Postby JaggedEdges » Thu Apr 21, 2016 9:28 pm

I have some experience with fluid dynamics also, and think it's likely that in some instances a low in height well formed teardrop could improve the overall aerodynamics of the combination. From skimming through, I'd give a kind of spitball of if your coefficient of drag is no less than about 0.4, your frontal area is no greater and the trailer is lower than the aerodynamically significant trailing edge of your vehicle, then you might have same mileage or even gain a tad. By a.s.t.e I mean where the bulk of the air departs the vehicle, for older trucks that may be the top of the cab, whereas with newer trucks it could be the top of the tailgate. For slippier sedans it would be rear edge of the trunk, but for some it might be at the roofline.

However, infernal combustion engines are stranger devices than most imagine, nothing is linear. Completely counter-intuitive is that your engine is not necessarily the most efficient at the speed where you get the best mpg, maybe for small 4 cyls, not so much for anything else. This is because efficiency, which is consumption per horsepower actually produced, and usually quoted technically as pounds of fuel per horsepower x hour, varies with load as well as engine speed. This is known as Brake Specific Fuel Consumption, if quoted as single figure it is peak value and not necessarily anywhere near peak output or peak torque.. https://en.wikipedia.org/wiki/Brake_spe ... onsumption

Now then, this can mean that a lightly loaded engine, like a big one, not pulling much, can be in a bad area for BSFC, only 30HP may be required to bowl it down the road, but maybe at this RPM and only 15% of it's rated output, it's sucking a particularly inefficient 0.6 pounds per HP x hour. Now if we place a higher demand on it 40HP, by dragging something, at the same speed, it might move into a more favorable area of the BSFC map, and only demand 0.45 pounds per HP x hour. So what is the fuel consumption per hour in the first and second case? Both identical, 18 pounds an hour, sorcery you say, no a direct consequence of the laws of thermodynamics as applied to internal combustion engines.

In the case of a smaller engine, it might already be near the best BSFC efficiency, it's more highly loaded, say 30% to produce the same output, now we might presume that in an "economy" car, the manufacturers have arranged this very thing, that at typical highway speeds it's in a good area on the BSFC map, by the design, valve timing and all other factors, with another passenger or two it might not change much, however, double it's load, by making it move twice as much, and it might scoot right over that good area of it's BSFC map and off the other side, resulting in higher specific fuel consumption per horsepower and getting very bad gas mileage overall.

However, this all jumps back to the aerodynamics again, the less change there is in that, the less change in load, with some outlier situations with lightly loaded large engines that there is wriggle room in the science to actually gain mpg with worse aero, and also lose mpg with better aero.

Weight tends to affect overall mpg less the longer your highway cruise is, because rolling resistance is most significant at lower speeds, and for of course, accelerating to higher speeds. At highways speeds it's dropped in significance to a few percent of total load. If total aero drag remained constant, the difference in load from weight and hence rolling resistance at speed between a regular car, and towing something half it's weight on another set of wheels, would typically be similar to having the A/C on or off.
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Re: Gas mileage ?

Postby Adirondackersouth » Sun May 01, 2016 10:50 pm

JaggedEdges wrote:I have some experience with fluid dynamics also, and think it's likely that in some instances a low in height well formed teardrop could improve the overall aerodynamics of the combination. From skimming through, I'd give a kind of spitball of if your coefficient of drag is no less than about 0.4, your frontal area is no greater and the trailer is lower than the aerodynamically significant trailing edge of your vehicle, then you might have same mileage or even gain a tad. By a.s.t.e I mean where the bulk of the air departs the vehicle, for older trucks that may be the top of the cab, whereas with newer trucks it could be the top of the tailgate. For slippier sedans it would be rear edge of the trunk, but for some it might be at the roofline.

However, infernal combustion engines are stranger devices than most imagine, nothing is linear. Completely counter-intuitive is that your engine is not necessarily the most efficient at the speed where you get the best mpg, maybe for small 4 cyls, not so much for anything else. This is because efficiency, which is consumption per horsepower actually produced, and usually quoted technically as pounds of fuel per horsepower x hour, varies with load as well as engine speed. This is known as Brake Specific Fuel Consumption, if quoted as single figure it is peak value and not necessarily anywhere near peak output or peak torque.. https://en.wikipedia.org/wiki/Brake_spe ... onsumption

Now then, this can mean that a lightly loaded engine, like a big one, not pulling much, can be in a bad area for BSFC, only 30HP may be required to bowl it down the road, but maybe at this RPM and only 15% of it's rated output, it's sucking a particularly inefficient 0.6 pounds per HP x hour. Now if we place a higher demand on it 40HP, by dragging something, at the same speed, it might move into a more favorable area of the BSFC map, and only demand 0.45 pounds per HP x hour. So what is the fuel consumption per hour in the first and second case? Both identical, 18 pounds an hour, sorcery you say, no a direct consequence of the laws of thermodynamics as applied to internal combustion engines.

In the case of a smaller engine, it might already be near the best BSFC efficiency, it's more highly loaded, say 30% to produce the same output, now we might presume that in an "economy" car, the manufacturers have arranged this very thing, that at typical highway speeds it's in a good area on the BSFC map, by the design, valve timing and all other factors, with another passenger or two it might not change much, however, double it's load, by making it move twice as much, and it might scoot right over that good area of it's BSFC map and off the other side, resulting in higher specific fuel consumption per horsepower and getting very bad gas mileage overall.

However, this all jumps back to the aerodynamics again, the less change there is in that, the less change in load, with some outlier situations with lightly loaded large engines that there is wriggle room in the science to actually gain mpg with worse aero, and also lose mpg with better aero.

Weight tends to affect overall mpg less the longer your highway cruise is, because rolling resistance is most significant at lower speeds, and for of course, accelerating to higher speeds. At highways speeds it's dropped in significance to a few percent of total load. If total aero drag remained constant, the difference in load from weight and hence rolling resistance at speed between a regular car, and towing something half it's weight on another set of wheels, would typically be similar to having the A/C on or off.


Hello Jag,
I appreciate the science behind the evidence. I wonder if my Highlander is at optimum BSFC?
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Re: Gas mileage ?

Postby JaggedEdges » Mon May 02, 2016 12:22 pm

Adirondackersouth wrote: I wonder if my Highlander is at optimum BSFC?


If you have the 6 cylinder 2GR-FE engine, there was some discussion "around" it at the Tacoma forum, with this BSFC map..
Image

Gets interesting from post 109, NSFW warning for language here though... https://www.tacomaworld.com/threads/201 ... 512/page-6

Not sure you have the same gearing, but you could compare your final drive ratios and mentally interpolate.

EDIT: BTW the 2GR-FE is in bold over the top, think the intent of the image was to show how they made the hybrid engine better, the numbers refer to that one, more detail in that thread.
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Re: Gas mileage ?

Postby noseoil » Sun May 15, 2016 1:45 pm

Average with a Nissan Frontier (2007, 2.5L 4 cylinder, 5 speed manual) with the trailer is 20.5 mpg. Worse if in the mountains & pulling on long grades.
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