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?

[bobman]

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

[Eric_Lisa]

BradW wrote:
I will tell you what the Lance factory rep told me back in 1995 when I was planning on ordering a truck to haul our camper. He said if we plan on hauling our camper a lot, get the biggest motor you can get (460 CI back then). He said the big motor will get the same or even better mpg hauling the camper than the smaller motor.

Bradw

Yup. Yanked out the stock 350 and installed a 383 crate motor. Mileage with the camper is statistically unchanged. But now it climbs hills a heck of a lot better!

-Eric

[Eric_Lisa]

If my quick math is accurate, it looks like you used around 10 gallons more gas on the 280 miles coming back with the camper. Another way to look at this is it takes one gallon of gas to haul your camper 28 miles - pretty reasonable! :B

Your mileage will go down with a camper and will vary with all the stuff already mentioned on this thread. My comment is around filling the gas tank. Are you sure the tank was full on the return trip? Sometimes 'fussy' fill nozzles will shut off long before the tank is full. Is it possible the first & third fill (presumably your home station) is less sensitive and completely fills the tank and the second fill (out on the road) did not?

Until I changed it, my truck would cause the gas station nozzle to shut off 5-6 gallons before the tank was completely full. That was because GM had a tiny vent hole at the top of the sending unit. I drilled it out to a 1/4 inch when I changed the fuel pump, and now I don't have that problem.

Anyway, just another variable to consider. At the end of the day this is a really small sample with which to base a conclusion. Go take your camper on a long cross-country road trip for "research purposes". (LOL - I drove a classic car from OR to MN and back last summer. I got much better mileage when I was in the 100% gas states and away from the west coast ethanol states.)

HTH,
-Eric

[BradW]

I will tell you what the Lance factory rep told me back in 1995 when I was planning on ordering a truck to haul our camper. He said if we plan on hauling our camper a lot, get the biggest motor you can get (460 CI back then). He said the big motor will get the same or even better mpg hauling the camper than the smaller motor.

Bradw

[Camp_woof]

I've rented the Cruise America truck camper twice on the V8 F150 (camper is lance 650) ... got 12.5MPH driving conservatively through the Sierra's.

Sounds like you are spot-on.

Air resistance goes up by your speed squared ...

Dave

[SidecarFlip]

burningman wrote:
If you read as carefully as you drive you’d see he ran at 65 with the camper on.

My mistake, I saw 75 and though wow... Even 65 with a Lance on a 150 is pushing it.

[Jayco-noslide]

It's all about weight hauled and amount of "drag" and a head wind makes a big difference. Even several hundred pounds matters and 1000 lbs. a lot. Secondary to those factors is the engine, transmission and driving style. My Ford Focus drops from over 40 on the interstate to under 30 in town. With our 30 ft. V-10 motor home towing a 3000 lb. car we get around 9. When we towed a small 5th wheel with a half-ton truck we got 10 or 11. Driving 65 instead of 55 will lower MPG 3-5.

[IBguy]

A big thank you to all who chimed in! Some good insights there, with the bottom line that the Boost part of Ecoboost is mostly? to blame. Still, I really am mostly comparing apples with apples - dry weight on both campers within a couple hundred pounds, both cabovers, very comparable rigs. And actually, my MPG test was more like 380 miles, not 280, about 90% flat desert. So I don't see an appreciable increase as being likely in the future. And a 44% loss in MPG now, vs. a 21% loss with the old rig? I still don't see what can explain that big a difference. Oh well.....

Once the shock of the big drop in MPG sank in, we pretty much accepted it, as deltabravo explained: b

deltabravo wrote:

I bought the rig to enjoy life and have fun with, cost isn't a factor in that equation. If higher cost of fuel due to low mileage was a concern (and budget constraint), I wouldn't have bought the rig in the first place.

[Kayteg1]

My dually with big camper makes 12-13 mpg at 60 mph. When I try 70 mph, the mpg will drop below 10.
When I drive empty at 75-80 mph, I will get the same 12 what I do with camper at 60 mph.
That said, I can tailgate semitrailer at 75 mph and with my camper still get over 12 mpg.
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?

[JIMNLIN]

jplante4 wrote:
Headwind/tailwind will make a difference. You'll need to average over a longer "out and back" trip to get real numbers.

Good point. A short one trip mpg number can vary greatly vs mpg that are taken from several trips.

Looking at other 3.5 EB owners mileage pulling 6k-8k trailers shows about the same mpg drop as the OP 3.5 engine/truck camper.

[jimh406]

Wind can make a difference in mpg even with a rig my size. As others have noted, see what happens when you slow down and/or ride a reasonable distance from other large rigs.

You’ll also note if you do some searches that most people report approximately the same MPG with Fifth Wheels and TCs. I think that clearly says the wind resistance is a huge factor.

[jimh406]

HadEnOugh wrote:
My tricked out Dodge RAM 2500 and Arctic Fox TC cruises very comfortably at 80MPH all day long down the highway..

I’m not the speed police or weight police, but it sounds like you are wanted by both. :). Have you checked to see how fast you stop at 80? Also, have you looked to see how many mpg you are losing at 80?

Finally, I’m hoping you aren’t planning to pull your new trailer at that speed. It is only getting worse from here.

[jplante4]

Headwind/tailwind will make a difference. You'll need to average over a longer "out and back" trip to get real numbers.

[Tom_M1]

Mileage with my '05 Tundra V8 went from 17 to 11 when loaded with an Outfitter Mfg popup pickup camper.

[HadEnough]

SidecarFlip wrote:
Anyone that goes down the road with a TC as heavy as a Lance on an F150 at 75 mph is asking for a death wish.

I sure as heck don't want to be anywhere around you.

That is insane.

Try driving more conservatively and your mileage will increase.

Better yet, get a more capable truck and drive sanely. It's a vacation, not the Indy 500....:R

This is interesting.

My tricked out Dodge RAM 2500 and Arctic Fox TC cruises very comfortably at 80MPH all day long down the highway.

I've put a gazillion miles on it doing just that. All over the country from Maine to Florida and out to California, Colorado, etc.

I wonder if different vehicles handle differently?

I just go the pace of the other traffic around me or get way out front of the other people if they are going 65 or something.

Never an issue with it not handling well in a straight line. Corners, yeah. You gotta slow it down, though it's surprised me how resistant to rolling over it actually is.

I've even had someone pull out from a driveway in front of me when going 50mph and had to swerve into the oncoming traffic lane and back very quickly and it didn't roll. I thought for sure it would have.