Lost 1.5 mpg....about right??????

[NYSUPstater]

Upon picking up our new BC 3560 SS, stopped and got things weighed before long trip home. 5er weighs 14,000 and pin weight of 2860. Grossed out at 22,500 lbs empty.

Truck: 2015 F350 XLT, SRW, cc, 4x4, sb, 6.7, 50 gallon T-flow tank, 3.55 gears.
MPGS are:
-- City/hi-way, 13-15 summer, 10-13 winter
-- Old RV 13,000, 2,000 pin, 21,700 gross---ave 10.5
-- Enroute to pick up new RV, ave 19.0 (truck alone no RV attached)!!

All above speeds at 70 hiway and 30-40 local streets

Coming back w/ new coach netted 9.0 mpg @ 70 mph on ave and had some cross winds.

Truck never once sneezed as it it did GREAT towing it.

Am guessing the drop in mpg's is due to extra weight or perhaps flat front compartment door area? OR just plain due to the wind? Seems odd that tho about same gross weight as old RV, that I would have lossed 1+ mpg. RV towed like a dream BTW. Any thoughts? FWIW, am due to change fuel filter within next 3k miles as one that's on now has been on since last May.

 

[danemayer]

My experience is that wind has more effect on mpg than just about anything else. We were towing yesterday at 65 mph and had some diagonal winds against us. 8.5 mpg. Today we towed at 75 mph with a tailwind. 10.5 mpg.

 

[fastcarsspeed]

Over 60 mph towing will greatly reduce your mpg. I just towed our Cyclone 4100 which is about 14400 from Charlottesville VA to Southern Maryland and I was at 10.5 mpg. I kept it under 65 the whole way and had some stop and go traffic. Also wind will also add to the reduced mpg. I have a 2011 F350 4X4 6.7 8' bed with delete package and programmer.

 

[travelin2]

Love those tailwinds!!! Drive north from MB last week on I95 then over I81, 600 plus miles, cruise set 63-64, 11.8 mpg!!!!
I was fueling in Winchester VA beside another SD owner towing a bumper pull long enclosed car trailer who struck up fuel a mileage conversation. Comparing mpg he winced when I said I was close to 12 mpg. He was getting less than 10 mpg SB into the wind running 70+ mph


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[rxbristol]

Oddly, when we were in Colorado and Wyoming, at higher altitudes, my truck got fantastic gas milage--towing, I was averaging 14.3 mpg. Now that I'm at a lower altitude, I'm back to 10.5 mpg.

 

[JohnD]

I got around 7 mpg while pulling to and from the Alto, New Mexico HOC Rally a couple of weeks ago.

Gas engine and 4.10 rear end, though . . .

 

[Garypowell]

I was fueling a few yeas back beside a big rig loaded with steel. I asked him what different mileage he got loaded and unloaded. He said 1 MPG.

I was floored.....he said mileage has very little relationship to weight.

And I figured he should know what he was talking about.

And I see this in practice as we pull....every day is different mileage all depending on multiple things like wind, speed, elevation, and grade.....the weight of the rig changes very little.

 

[cemill]

We just returned from the Missouri Rally.
going we averaged 9 mpg at 65 mph with a heavy quartering cross wind.
Coming back home Sunday at 65 mph with very little wind averaged 11.3 mpg
The wind makes all the difference in the world.

 

[Shortest Straw]

We just completed a trip from KY to Casper WY. We had heavy crosswinds all the way across IA and NE. I tried slowing to 65 and resetting my fuel mileage average on the dash and did not see more than a couple of tenths difference between 65 and 70-75. We usually get about 9-10 mpg and that dropped to 7-8 across those two states. Once we got to WY we were in a head wind and were averaging a bit over 8.

The wind speeds we were up against this trip averaged no higher than 25 mph. While I do not concern myself about fuel mileage much more than just paying attention for engine health reasons, it seems to me it is what it is. IMO while a person may save a buck here and there in fuel costs, these big fivers still have a bunch of drag on them that cannot be overcome.

 

[dave10a]

Friction goes up by the square of the speed. Head wind is the largest component of friction for towing.

 

[NYSUPstater]

Thanks for the replies. Really thought it was just me/our rig, but everyone has had pretty much the same results as what we experienced.

 

[JohnD]

I've been considering taking the tailgate off when pulling to see if that changes the MPG's . . .

I'd like to get a louvered tailgate, but I've got too many other things to spend $400 bucks on these dayz . . .

 

[dave10a]

Contrary to popular opinion, the tail gate down causes more drag and increases fuel consumption.

Here is a wind tunnel test that is interesting.... http://www.autoblog.com/2014/08/26/ford-f-150-tailgate-up-down-mpg-video/

 

[JohnD]

That's without the big front end of a 5th-wheel trailer covering up half of the box . . .

How about with a 5th-wheel trailer hitched up?

 

[Alan_B]

I lose a lot more than 1.5 mpg when towing the fifth wheel.

Clean long-distance highway mileage for the truck without the trailer is about 20 mpg.

Pulling the fifth wheel over the last 1,000 mile trip we averaged 11 mpg.

Both numbers probably owe something to the 3.10 rear axle ratio.

 

[Bob&Patty]

Gary, big rig engines are rated by gallons per hour at a certain RPM. Loaded or empty they all get about the same MPG. Well at least every one I ever owned/drove.

 

[Shortest Straw]

I've been considering taking the tailgate off when pulling to see if that changes the MPG's . . .

I'd like to get a louvered tailgate, but I've got too many other things to spend $400 bucks on these dayz . . .

In the battle to brag about the best mileage with pickups these days I would be willing to bet that the manufacturers would be offering louvered tailgates if they indeed improved mileage at all. I read on the irv2 forum that someone had been hauling their fifth wheel without the tailgate, left it on for a trip, and his fuel mileage increased.

 

[HOOKERUP]

Did anyone buy the truck for fuel economy, or what it's meant to do. Just asking.

 

[fastcarsspeed]

If fuel economy was a concern then we would be looking at weight of the rv and also looking at items such as a roof wind deflector to put on top of the truck to deflect wind. Also I guess we could look at fashioning those fuel saver wings that we see on trailers these days that help with wind on the underbelly of the trailer and also the tail.

 

[wehavefun]

I personally don't think those fuel saver wings, fairings or tail wings will prove any savings on fuel verses initial costs. If you gain 1 mpg, how much would you save in an average year?

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