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guskmg · 03-20-2021, 04:23 PM

It is pretty simple because diesel engines will get about 40% better milage due to more BTU per gallon than gas engines. Gassers will get 7-8 while diesels will get 12-14 mpg. Out West there is a lot of biodiesel and ethanol laced gas. Both get less mpg than straight fuel. I have seen info that says the enviromental cost of our smog equipped diesels accounts for 3-4 mpg. It all adds up to better mileage with emproved efficiency, but we pay a penalty for cleaner air. Without the smog equipment and using straight fuels we would be getting 4-6 better mpg.
guskmg

27ftToaster · 03-20-2021, 06:25 PM

We have a new 2020 2500 RAM Limited with the Cummins Diesel (still under 9,000 miles). We find it to run about 11 mpg with our 27' FC in tow. I have to admit, that we have a heavy foot and tend to push 70 - 75 mph, while others are doing 80. I know that costs us MPG, but... we have places to go... things to do...

n2916s · 03-21-2021, 09:27 AM

Quote:

Originally Posted by 27ftToaster

We have a new 2020 2500 RAM Limited with the Cummins Diesel (still under 9,000 miles). We find it to run about 11 mpg with our 27' FC in tow. I have to admit, that we have a heavy foot and tend to push 70 - 75 mph, while others are doing 80. I know that costs us MPG, but... we have places to go... things to do...

At 9000 miles your engine isn’t really broken in yet. Mine improved about 20% from new by the time I had 24000 miles on it.

AnnaBelle33 · 03-21-2021, 10:09 AM

I have a 2019 RAM Diesel Limited with a ‘21 Classic 33 and we keep it at 65 mph and I get 15 mpg in Florida & Georgia. We plan on hitting TN, NC, VA & WVa this year and I’m sure it will drop in the bigger mountains.

SuperTrouper · 03-21-2021, 12:20 PM

2008 27FB with 2002 Excursion 7.3 with 300K on the clock. Full water tank. 62 mph. 11.5 MPG, 12 on a good day. EX get's 17MPG when not towing.

CMHM · 03-21-2021, 06:04 PM

Thanks for all the replies. Since I was driving between Las Cruces -> Roswell with high wind warnings that must have been the determining factor in terms of fuel consumption. Will definitely use cruise control less too when going up and down hills!

JayOhBee · 03-21-2021, 06:21 PM

2015 Ram 2500 diesel, 2012 FC 30RB. Pretty steady 14MPG at 63-65MPH. Wind and speed seem to be the two biggest factors.

vwii · 03-21-2021, 07:22 PM

10-13 mpg depending on who's driving and the terrain. 2014 Tundra 5.7 towing 28 foot Flying Cloud. Interestingly (at least to me) the non-tow mpg isn't all that much different, around 14.

Dick tracy · 03-24-2021, 09:57 AM

I've been rving for 20 years, started with class a diesel pushers, 8 MPG didn't matter if it were hills or flat trips, wind, all the kids or just the wife, always 8 MPG. moved to an AS a few years ago and am happy with any above 8 MPG.
currently getting 9-10 MPG with a 2019 F150 v8 gas, love it.
don't love the gas prices in CA or during the Obama/Biden war on energy policy years. was happy with Or/Wa $2.65 gallon.
Elections have consequences.

Milo1952 · 03-24-2021, 10:07 AM

Quote:

Originally Posted by albret

Agree with most everything everyone has said. I pull a 28 foot with a 2500 Dodge diesel. Speed does affect your mileage per gallon. Hold your speed down to nothing over 65 MPH. I get about 19 MPG with calm winds and flat roads. Going down hills with gentle slopes will give me 23 MPG. Steep hills drops the MPG to about 15-16 MPG. Many people pass me on the road, but what is the hurry? They arrive 5 minutes before me or get backed up in traffic and arrive at the same time. An under-powered vehicle will also eat up additional fuel.

You get 19 mpg towing ! Is your vehicle before "def" days? Or did you do a DELETE on the emission control system?

Aznomad450 · 03-24-2021, 10:55 AM

I have pulled my 1991 - 25' Excella all over the nation and until recently I always used cruise control or not and experienced the same general fuel mileage. The truck engine was bullet proofed in 2014 and I run a SCT towing programmer. I would engage tow/haul on my shift lever when in mountainous areas and before exiting the interstate in order to use the engine as a brake, but otherwise disengaged it while at Interstate speeds.

Last year I decided to leave tow/haul engaged full time. The engine RPMs remain at a slightly higher range when doing so which obviously puts the engine in a sweet spot. After all these years I am now getting an average of 1.5 to 2 mpg better fuel mileage. Go figure. Think of all the fuel I wasted by not using a feature that was factory built into my truck.

Daquenzer · 03-24-2021, 11:46 AM

I tow 28’ with F150 Ecoboost. I get 10 to 12. The main difference is speed, wind, hills. For every 5mph above 55 mph mpgs drop significantly. If I drove 55mph I would be at 12mpgs on a cosistent basis. I seldom drive over 65 for a number of reasons, but basically at 70mph mpgs go down significantly, and I don’t get there any quicker anyway since I stop about every 2 to 3 hours. But at 65 mph mpgs are just above 10 (as an average). And I always tow in tow haul.

And I think aerodynamics plays a bigger role than we realize. I have a 7x12x7 cargo trailer that weighs far less than AS. And I can’t get above 10mpgs with that. And most often at 9mpgs. And it is all about aerodynamics.

cricket · 03-24-2021, 11:59 AM

I’ve been using old school equipment compared to what everyone else is using. I have a ‘52 22 ft Flying Cloud and tow it with a ‘53 Ford country squire. I don’t get any better mileage than other people are quoting here, even though my combination is considering lighter in weight than new. On the truck scales my combination weighs in around 5500 lbs. the best mileage I ever achieved towing is 11 mpg, while running solo I’ve gotten 18mpg. The old saying is that it takes gas to produce power, you’re going to use more under load. I think the tow ratings of the new trucks are well beyond the abilities of the vehicle. It’s ridiculous to assume that a half ton truck is going to be able to tow 10,000 lbs with a small motor, the tires, brakes and chassis are too light for that kind of weight, not to mention that you’re going to cut the life of the motor by working it that hard. It takes as much energy to stop a load as it does to get it moving, if some reason you were have to make a emergency maneuver with a overloaded combination, you’re guaranteed to be wrapped up in whatever is in front of you.

MikeAnkorage · 03-24-2021, 12:06 PM

Elevation can have an extreme effect, even with modern turbochargers. My first lengthy tow experience included I-40 in New Mexico. Speed limit was 75, as I recall. I kept the VW TDI pulling at no more than 70. That tank of fuel went by really quickly.

Mom2twins · 03-24-2021, 02:38 PM

Interesting thread - just returned from a 450 mile trip from N Cal to S Cal and was wondering the same.. driving up mountains to 5000' and through the grapevine on I5. Got better mileage on the way there up the mountain than on the way home but it was several hours of high wind gusts coming home.. makes sense now reading comments. Guess I am happy with my avg 11.5 mpg with my Ford Expedition.. I towed in 2WD but wondered if 4WD uphill on the mountain would be better... I did downshift to 2nd and 3rd out of overdrive for the uphill climb.

Shiny16 · 03-24-2021, 04:12 PM

Quote:

Originally Posted by n2916s

Inland Andy did a whole article on how an airspeed indicator on the tow vehicle would help you maximize your mileage.

That man was unique...

True or indicated?

David in Lex · 03-24-2021, 05:41 PM

We tow our FC 30 with a 2020 F150 EB max tow package. We average 12 mpg over 7500+ miles in all kinds of terrain , weather, etc. I don’t use cruise when towing but I do use the tow mode transmission setting. I keep it around 60 and try to stay under 65. We have a ProPride hitch. I have no idea what effect if any that has on fuel mileage.

VacuumKing · 03-24-2021, 07:03 PM

Two things I did not read hear.
That mpg you will find is off by 2-3.
A side wind is more drag than a head wind.
Do a tank and divide the gal. into the miles. My idiot meter tells me I get 12.8 mpg.
25 gallons at 275 miles. I get 11.
2016 v6 eco
I do 70 most of the time. I know, I need to slow down.

AZ camper · 03-24-2021, 10:27 PM

Quote:

Originally Posted by Dick tracy

I've been rving for 20 years, started with class a diesel pushers, 8 MPG didn't matter if it were hills or flat trips, wind, all the kids or just the wife, always 8 MPG. moved to an AS a few years ago and am happy with any above 8 MPG.
currently getting 9-10 MPG with a 2019 F150 v8 gas, love it.
don't love the gas prices in CA or during the Obama/Biden war on energy policy years. was happy with Or/Wa $2.65 gallon.
Elections have consequences.

Unfortunately we haven’t seen the end of gasoline price increases. Oil and gas leasing and drilling permits have been suspended on federal mineral estate including offshore. Domestic oil companies are no longer investing in new exploration or prospects because of the hostility of the current administration. Domestic supply will decrease over time and demand will continue to increase. I spent 35 years as a federal oil and gas geologist and am glad to be retired.

uncle_bob · 03-25-2021, 07:16 AM

Quote:

Originally Posted by VacuumKing

Two things I did not read hear.
That mpg you will find is off by 2-3.
A side wind is more drag than a head wind.
Do a tank and divide the gal. into the miles. My idiot meter tells me I get 12.8 mpg.
25 gallons at 275 miles. I get 11.
2016 v6 eco
I do 70 most of the time. I know, I need to slow down.

Hi

At least the way I run things (when I put in fuel, I always fill the tank), the MPG indicators have been very close on the last few vehicles I've owned. Comparing the computer's numbers to the "fill up" numbers is normally within a tenth.

Bob