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07-18-2017, 06:45 PM
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#21
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Senior Member
Join Date: May 2015
Location: Ames
Posts: 297
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I think speed was your main issue, maybe some headwind too. I have towed on 80MPH interstates in South Dakota, still went 64-66. It was very hot, so the tires were even under more stress due to the heat. Don't worry, people will pass you and you will rarely find yourself having to pass someone (although it does happen). I have also passed trailers that flew past me at well over 65 with flats on the side of the road several miles later.
My F150 and my ram have noticeable differences in mileage at 55-65 and certainly 65+, and as others have said, check those tires. Hard to find them rated with more than 65MPH speed ratings. I think I saw 6.5-7 in the F150 once, it was pretty heavy headwinds.
Something like Fuelly GasTracker + is useful for tracking your mileage, I use it on my truck, tag the trips I have the camper so I can separate those out, gives me a really good estimate of my overall towing experience.
__________________
2016 Jayflight 29BHDS
2015 Ram 2500 Laramie Crew Cab - 6.4 Hemi
2013 Ford F150 Supercrew EcoBoost, MaxTow (Loved and Sold)
ProPride 3P
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07-18-2017, 06:47 PM
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#22
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Junior Member
Join Date: Sep 2016
Location: Amsterdam
Posts: 27
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I've been getting 11 towing a 17 31QBDS, probably 11k loaded with a 16 3.5 3.55 max tow. Any chance it got out in 4wd on accident? I forgot to switch out once and got about the same
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07-18-2017, 08:30 PM
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#23
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Site Team
Join Date: Nov 2012
Location: Clearwater, FL area
Posts: 5,196
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We get 9 - 10MPG towing a 284BHS at 62MPH 3:73 gears and HD/Max tow pkgs. Move up to 65 and it drops to a solid 9. So, 62 is the max, mostly for safety reasons. At 55 it is close to 11 MPG.
Your speed is the reason for your lack of MPG and safety.
Don
My Registry
RVing with SOLAR
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07-20-2017, 07:45 AM
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#24
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Junior Member
Join Date: May 2017
Location: Williamston
Posts: 19
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The worst I've ever had in our '15 F-150 3.5l eco was 9 mpg. I actually did a test on the last trip we took, drove 70 to the campground and 60 on the way back and only saw a 2 mpg difference.
As others have said I think speed is really what is killing you, I've never driven above 75 and not for an extended period of time.
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07-20-2017, 10:22 AM
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#25
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Senior Member
Join Date: May 2015
Location: Ames
Posts: 297
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Quote:
Originally Posted by spotdog14
The worst I've ever had in our '15 F-150 3.5l eco was 9 mpg. I actually did a test on the last trip we took, drove 70 to the campground and 60 on the way back and only saw a 2 mpg difference.
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2 MPG difference between 60 and 70mph is pretty significant. Curious Was it relatively flat and not windy so each direction should have been equivalent work? Taking 10mpg as a base, thats a 20% fuel economy difference for 10mph speed difference.
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__________________
2016 Jayflight 29BHDS
2015 Ram 2500 Laramie Crew Cab - 6.4 Hemi
2013 Ford F150 Supercrew EcoBoost, MaxTow (Loved and Sold)
ProPride 3P
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07-20-2017, 03:28 PM
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#26
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Member
Join Date: Sep 2015
Location: Round Rock
Posts: 81
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What a drag
There are several types of drag but, in the RV arena we are most concerned with PARASITIC DRAG. Parasitic drag is a combination of form drag, skin friction drag and interference drag. The kicker is the faster you go, the more parasitic drag you produce, i.e., go faster = more total drag.
Some may have aviation experience and wonder about induced drag, a byproduct of lift which reduces with speed. Our Jaycos may not produce much lift but, they generate a bunch of drag.
Headwinds and tailwinds directly affect drag.
Bottomline: Faster towing speeds means more drag. Resulting in more fuel/money.
__________________
2016 Jayco 23RB
2006 Ford F-150 Supercrew 4x4 5.4
<><
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07-20-2017, 04:44 PM
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#27
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Senior Member
Join Date: Jul 2017
Location: Tucson
Posts: 661
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I have a 2014 F150 crew cab, work truck with 3.5, twin turbo and a shell on the bed. I had to tow an empty trailer (small trailer back from Yuma to Tucson). I usually fill up in Yuma, then after I'm back in Tucson I usually have another 2 days of around town gas before I need to fill. Not with this little single axle empty trailer. Once you get into the turbos a little bit that 3.5 sucks it down. 17 MPG is what I usually get with cruse control set to 80. With this trailer attached I was getting about 7.5 MPG and had to fill 50 miles outside of Tucson.
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07-20-2017, 05:06 PM
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#28
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Senior Member
Join Date: Sep 2016
Location: Everett
Posts: 264
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That's crazy! It sounds like you have the 2017 model with the 10 speed. I have a 2016 pulling the 25BHS with a CAT scale weight of 6800lbs camping weight. I was getting 10-11 mpg but it dipped down to 9 mpg after I put on the BFGOODRICH KO2 33's. My trip consists of leaving the Seattle area and heading over the pass (Stevens Pass) to Chelan and other areas. Lots of hills with mine switching between 3rd and 4th gear and sometimes dropping into 2nd but I only have the 6 speed Ecoboost Lariat with max tow.
I would continue to monitor to see if it changes. Then contact the dealer if it persists. Did you make any modifications to the truck? Tires? Suspension? I have made mods like tires, RAS suspension, 1.5" front leveling kit, and K&N intake filter. I only lost 1-2 mpg.
Crazy
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07-20-2017, 07:24 PM
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#29
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Senior Member
Join Date: May 2015
Location: Ames
Posts: 297
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Quote:
Originally Posted by Rivercityjeff
There are several types of drag but, in the RV arena we are most concerned with PARASITIC DRAG. Parasitic drag is a combination of form drag, skin friction drag and interference drag. The kicker is the faster you go, the more parasitic drag you produce, i.e., go faster = more total drag.
Some may have aviation experience and wonder about induced drag, a byproduct of lift which reduces with speed. Our Jaycos may not produce much lift but, they generate a bunch of drag.
Headwinds and tailwinds directly affect drag.
Bottomline: Faster towing speeds means more drag. Resulting in more fuel/money.
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https://www.ford.com/towingguides/
See attached on the 2016 and 2017. On my F150 I did note the "frontal area considerations" of 60 sq feet, probably directly related to this drag. I had a max front area of 60 sq feet on my f150 according to this guide, I have a feeling most Travel trailers are really pushing that number being they are so tall.
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__________________
2016 Jayflight 29BHDS
2015 Ram 2500 Laramie Crew Cab - 6.4 Hemi
2013 Ford F150 Supercrew EcoBoost, MaxTow (Loved and Sold)
ProPride 3P
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07-22-2017, 08:17 AM
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#30
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Senior Member
Join Date: Sep 2012
Posts: 191
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16' 24MBH + 17' F-150 3.5 EcoBoost = 5.8 mpg??
Quote:
Originally Posted by kjandb
Thanks for all of the suggestions. Yes, I was probably going a little faster than I should have...maybe 78? Speed limit is 80.
I'm headed out again next weekend on mostly highways (65 mph) instead of interstate. I'll see if that makes a difference.
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Dude, I'm not going to be your mother, but that speed pulling a trailer is stupid. No, STUPID! One twitch of sway, and you won't have time to bend over and kiss your $&#% goodbye. If you'd see what I have in close to 3 million miles of driving, you'd probably stay home. Be sensible. You'll get there. Might as well do it in one piece,
Have you set your fuel use to "towing" in the dash screen? From normal? While it adjust the "Distance to empty" I think it compensates for the change in the way the truck figures fuel usage.
Also, the fuel use over 55mph jumps exponentially for all vehicles, which is again exponentially affected by wind drag from your massive sail behind you.
Cut back to 65mph and watch it drop substantially. For fun, kick down to 55mph when possible, and watch it drop even more.
Switch your screen to watch the boost gauge. When you see blue, fuel is pouring through the injectors. More blue, more fuel. Guaranteed, anything on the hitch produces boost, and a blue band on your boost gauge. At high speeds, you are out of your sweet spot, and likely, that gauge will show you sucking fuel.
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07-22-2017, 10:05 AM
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#31
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Senior Member
Join Date: May 2013
Posts: 1,588
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As stated before, drag is an exponential function. If you double your speed, you quadruple your drag. The increase in drag between 65mph and 75mph is much greater than the increase from 55mph to 65mph.
I fly large jets for a living. I see this on large scale often with our fuel burns with respect to airspeed. Our flight planning is largely based on fuel economics since it is such a massive cost.
I don't believe there is any induced drag factor in towing trailers.
As an added note, towing at high speeds into a headwind is a double hit against you. If you are driving 60mph into a 30mph headwind, the truck is fighting 90mph of wind which as explained above, is a massive (exponential) increase in drag that has to be overcome. The second penalty is that even though you are powering through all that drag, you are only traveling 60 miles for each hour of driving, rather than 90.
When we cruise in the jet, we often slow it back to take advantage of the reduced fuel burn while still maintaining a good ground speed.
__________________
2013 F-150 EcoBoost MaxTow, Roush tuned (415hp 506tq), lifted on 33s, R.A.S.
2013 Jay Flight 28BHS Elite (Equalizer 10K hitch)
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07-23-2017, 01:19 PM
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#32
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Senior Member
Join Date: Nov 2010
Location: Pahrump
Posts: 4,036
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5.8! You didn't mention your speed but if we assume it was near 60, a modest headwind shouldn't cut your MPGs 40%. Rolling hills not a mileage killer. Altitude, not with turbos. I doubt your truck was grossly overloaded. With all the car/engine experts on this forum I'd expect some more suggestions are forthcoming.
Even with my bias that this engine is not a good idea for towing, <6 indicates something is amiss.
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'11 Eagle 320RLDS
'02 F350 PSD Dually 4WD
DW's Ride, '13 Expedition
'14 Denali XL
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07-23-2017, 01:46 PM
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#33
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Senior Member
Join Date: Jul 2017
Location: Tucson
Posts: 661
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Regarding my earlier post, I was referring to a single axel lighweight landscaping trailer, not a travel trailer 😄. I would never go 80 with a travel trailer.
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07-23-2017, 01:49 PM
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#34
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Senior Member
Join Date: Jul 2017
Location: Sheep Creek, ID
Posts: 119
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That sounds like terrible mileage have you thought of upgrades to your engine, we tow our 27ft White Hawk with my wife's 2008 Nissan Armada and get 11 to 15 mpg.
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