Shocking mileage drop

[IBguy]

Ten years ago we had a lightweight camper (don't recall the brand or model) on my Tundra Supercab with a V-6. That camper dropped my mileage on the road from 24 to 19 MPG.

Many years later, we just bought a Lance 815, very lightweight camper for our F-150 Supercab with a more powerful V-6 than the Tundra had. Our mileage in driving 280 miles to pick up the camper was 21.7 MPG, averaging 75 MPH. But on the way back with camper driving 65 MPH, it fell to 12.3!!! :? What the heck? :h

Any thoughts on why our MPG dropped so dramatically, and what, if anything, we can do about that?

[Kayteg1]

towpro wrote:


The thing I found strangest is my best tank MPG (both directions) was running the 77 / 81 through the NC/VA mountains. and its up hill going home.

It is perfectly normal.
It is the wind resistance that is the biggest factor in mpg.
It goes up with square of the speed, so even 10 mph difference can generate big mpg difference.
Going over the mountains you are forced to drive slower.
So even grades lower mpg in small %, the lower air drag at lower speeds. will leave you better mpg.

[twodownzero]

IBguy wrote:
Ten years ago we had a lightweight camper (don't recall the brand or model) on my Tundra Supercab with a V-6. That camper dropped my mileage on the road from 24 to 19 MPG.

Many years later, we just bought a Lance 815, very lightweight camper for our F-150 Supercab with a more powerful V-6 than the Tundra had. Our mileage in driving 280 miles to pick up the camper was 21.7 MPG, averaging 75 MPH. But on the way back with camper driving 65 MPH, it fell to 12.3!!! :? What the heck? :h

Any thoughts on why our MPG dropped so dramatically, and what, if anything, we can do about that?

My Lance 815 weighs 2200 pounds. You put that on an F150? You should be thankful you're alive, not complaining about the fuel mileage.

[towpro]

it happens to diesels as well.

2018 Ram diesel, Aisin trans, 3:73 gears, 2wd, Dually

with arctic fox 990 loaded, towing Jeep Liberty with tow bar, running 55 mph = 11-12.

same truck towing 7x14 V nose trailer, around 4000 lbs, no camper loaded. 70 mph highway (2000 mile trip) 11-12 mph both directions, going down it was loaded, coming home it was empty so this is indicating wind load, not weight

same truck empty, running PA turnpike @ 70 mph, 200 mile RT 20 mpg.

The thing I found strangest is my best tank MPG (both directions) was running the 77 / 81 through the NC/VA mountains. and its up hill going home.

[Grit_dog]

4 full pages later, none of the stories corroborate the OPs claim of 19mpg with his camper on the old truck......keep up the stories though.
Good entertainment.

[wvabeer]

My 13 f150 ecoboost get only good mileage empty. TC in it 9 10 mpg with or without a toy in tow. I liked that either eco or boost you can't have both. 🙂 Thats a fact. Toys are going to cost ya. Have fun.

[Kayteg1]

jimh425 wrote:

BradW wrote:
http://www.fuelly.com

Could be a very useful site if the data was a bit better. There is no mention of avg speed that I found, or if there was a load or trailer if any. Maybe it is there.

For F-450, E-450 Class Cs are mixed in. 🙂 I’m thinking a Minnie Winnie v-10 isn’t quite the same as a F-450 pickup.

Nothing in this life is perfect, but fuelly indicate % of city driving at each fill up. Question is how many owners bother to observe it.
I also put notes what the vehicle computer shows in mpg -comparing what is the actuall fill and note trailer or camper hauling.
Talking about ClasC with V10 gasser in them - I drive my TC combo at 60 mph for fuel saving and often see those rentals zooming by me.
My estimate is that they average 5 mpg, but with big tank they do not notice it -till 300 miles later, when they have to drop $200 to fill.

[kohldad]

Each engine has its "sweat spot" when it delivers best mpg and each time I drive 40 mph highway my mpg will skyrocket, but who wants to drive that slow?

Me! I love to get on the back roads without traffic and run this slow. The adventure to me is getting there and driving slow allows me to enjoy the scenery along the way. Please note - I did say without traffic as I know most folks won't.

I sure wish I could get 24 on the highway with my 1-ton running empty at any speed. Running 75, I would only get around 16 if it was pure interstate. Running 65 I only average about 18 if the traffic is heavy and flowing. Now hauling the camper I can get about 13 on the interstate. But my average after 35,000 miles with the camper is 12.3 mpg (hand calculated).

One of the things is if you are using the overhead computer or hand calculating the mileage. I know with my lie-o-meter, I'm about 15% off when running empty but usually only about 8% off when running with the camper.

[jimh406]

BradW wrote:
http://www.fuelly.com

Could be a very useful site if the data was a bit better. There is no mention of avg speed that I found, or if there was a load or trailer if any. Maybe it is there.

For F-450, E-450 Class Cs are mixed in. 🙂 I’m thinking a Minnie Winnie v-10 isn’t quite the same as a F-450 pickup.

[BradW]

http://www.fuelly.com

[Jayco-noslide]

10 MPG seems to be the magic number when towing anything very heavy so over that is good.

[happycamper1942]

I've had 3 different trucks and 5 campers,a Chevy gas,a Ford gas and a Ford diesel. In all cases I got 12mpg. I figure no matter what you have, be happy with 12mpg

[BarabooBob]

I have an Ecoboost that gets 20 mpg without my trailer. I geet about 1.5 to 11 towing my TT. Frontal area makes all the difference. I love my Eco, that thing climbs hills like nothing is behind you. BUT, look at your instant read mpg bar graph, it shows you are getting very poor mpg with the boost wound up. By the way, I tow at about 60 mph, my mileage does go up when I slow down.

[IBguy]

bobman wrote:
Could be the old truck had a more favorable differential gear ratio for the speed you were traveling

That's a reasonable possibility. Not much I can do about that, though! :W

And by the way, some of you mentioned headwinds. There were none.

Now that I realize that I have to stop for gas every 200 miles, I'm OK with it. I like stopping about every 3 hours anyway, just to stretch, pee - the usual. BTW, our other car is a Hyundai Ionic; great little car, not as goofy looking as a Prius, and gets 55 MPG at 75 MPH. When I average that out with the 12 MPG camper, it ain't all that bad a deal.

[free_radical]

Headwind or tailwind will make a big difference..and SQUARE box aka camper will slow you down and reduce mpg big time..

One reason I built my TC rounded aerodynamic in front and light,so get almost same mpg with or without it on truck..

Also small V8 motor will get better mpg then turbo six..mine idles at 1600 rpms at 110klicks..