One of the biggest campfire questions has to be What is the Fuel Economy of your RV? or What is the MPG of that RV? Calculating the MPG or Fuel Economy of your RV is a pretty simple task, but ask one of these questions around the campfire and you’re likely to get a fisherman style story!

I’m not saying I’ve never done it, we’ve been calculating our RV MPG for years with our Monaco Vesta (you can see that info here: gonewiththewynns.com/vesta-fuel-economy) Nikki has occasionally caught me exaggerating when chatting up our RV fuel economy. What I have not done is tell a giant lie like “our 40 footer gets 16 Miles Per Gallon!”….come on people that’s just ridiculous.

So how do I calculate the MPG or Fuel Economy of my RV?

If you’re good at keeping a log there are plenty of apps that make tracking MPG, price, miles driven, etc. a breeze as long as you remember to do it at the pump. We’re not that disciplined (usually after dropping a couple hundred bucks at the pump the last thing on my mind is filling out a questionnaire).

I keep track of all my receipts, notate the RV Mileage, and file away in a box above the driver’s seat.

The Computer on your RV is not a MPG calculator, it’s more like a video game…its made for entertainment purposes only! This little computer can’t monitor every detail about the fuel consumption of your RV, but it can help you get an idea of your RV’s best engine RPM and teach you not to have a lead foot or perform “jack rabbit” starts at the stoplight.

Below are my Miles Per Gallon calculations for Roy, our 2014 Fleetwood Excursion 33d. If you don’t have an Excursion you can take these calculations and guesstimate for just about any similar size, weight, and shape of RV that’s using a Cummins engine. Keep in mind we are towing a Smart Car which has a small footprint and weights a lite 2,000 pounds. We also keep the speed between 55 mph and 60 mph, so if you have a heavy right foot your MPG will likely be much lower. Before we departed Indiana our RV was weighed in at 24,500 pounds loaded (with with all our gear and the tanks approximately half full) and our tire pressure was adjusted for maximum performance and safety.

 

05/2014 – 08/2014 Conklin Fuel Supplement Test: Flat, Boring and Hot as Hell!

In March we had a reader contact us to see if we’d like to get better fuel economy in the RV. He said “I love your website…I’m a private supplier of Conklin products and they can provide your RV with a cleaner engine and better fuel economy.” I said “duh, of course we’d like better MPG“. So he sent us one bottle of Conklin 4-Power D to clean out the engine, and one bottle of Conklin Diesel Plus Fuel Conditioner to improve fuel efficiency. I waited to use the product till we crossed the Appalachian mountains so the terrain would be more flat. After running both bottles through I was concerned we wouldn’t get a real reading with only 2 fill-ups, so I got one more bottle of the Diesel Plus. So here’s the scoop on our Conklin Diesel Fuel Supplement Test in our Fleetwood RV:

Route: Bardstown, KY to Walnut, IA (via MI and da UP)
17,047 Starting Mileage
19,392 Ending Mileage
2,345 RV Miles Driven
276.749 Gallons of Diesel Used
$1,030.74 Total Diesel Cost
8.48 MPG Sub-Total
34 hours of generator use
17 gallons of generator fuel consumed (approximate)
*7 gal of DEF used (approximate)

9.02 MPG for the Fleetwood Excursion with my Conklin Diesel Fuel Supplement test

I have done a few things “wrong” in this test that most likely influenced the readings:

• In my other tests I haven’t really used the drivers A/C, but this stretch of travel was extremely hot, so I pretty much rant the A/C non-stop on the “MAX” setting. I’m sure this has thrown off the MPG reading.
• Conklin recommends changing the fuel filter after using the 4-Power D but I feel unless I needed a new fuel filter the expense of this service will cost far more than what I would save in MPG; so I didn’t spend the money on a new fuel filter & service.
• Our diesel engine is barely broken in at 17,000 miles, so I’m guessing the engine is pretty clean, so maybe an older RV will benefit more from these supplements?
• It’s nearly impossible to know the amount of fuel consumed by the generator unless you document every device run, including the watts, time run, etc while using the generator, but I’m not that patient.
• Filling the DEF is a pain and some places don’t have it, so I just made note of the DEF reading at the start and finish of the MPG test, so that’s why it’s “approximate”.

*My trip computer is a little optimistic, as is typical with RV MPG computers

I wish I could have reported a 1-2 MPG increase but it’s not the case with this test. So compared to my other RV Fuel Economy readings it doesn’t seem that the Conklin products helped me achieve better MPG. I’m not saying the products don’t work, and I’m sure the lower MPG reading can be attributed running the HVAC in the drivers area. Please know Conklin has run their own tests and they stand behind their claims about performance, value and longevity; and when I flip through their website it seems they have plenty of happy customers that claim better fuel economy and cleaner engines. If you use any fuel supplements in your RV tell us about it in the comments below.

Just for fun here’s the Smart Car info for the same time frame:

1182 miles driven
32.94 gallons of Premium Gasoline
35.89 MPG for our little Smart
Now if only we could have a diesel Smart car here in the states…now that would be AWESOME fuel economy to report. Till next time we’ll keep truckin’ along and trackin the RV fuel economy. Please share your RV make, model, year, size and MPG in the comments; we love comparing RV Fuel Economy readings.

01/2014 – 02/2014 Big Winds, Mountains and Desert

Our Excursion has a liquid urea tank so I decided to make my first Miles Per Gallon calculations based on 5 gallons of DEF. We filled up in Wichita Falls, TX as we headed north towards the Rocky Mountains. We battled a gnarly head wind for around 30% of the drive and a severe cross wind the remainder of the nearly 1000 mile trip to Breckenridge, CO. We also drove in the Rockies with giant climbs and descents…so to say this is an unbiased real world test would be an understatement.

Route: Dallas, TX to Breckenridge, CO to Cloudcroft, NM to El Paso, TX
12,679 Starting Mileage
14,261 Ending Mileage
1,582 RV Miles Driven
169.448 Gallons of Diesel Used
$28.12 approximate DEF Cost
9.34 MPG Sub-Total
10 hours of generator use (approx)
5 gallons of generator fuel consumed (approx)

9.62 MPG for the Fleetwood Excursion based on this first test

I have done a few things “wrong” in this first test:

• I didn’t reset all my MPG, miles driven, etc on my CPU to get an accurate idea of the bias of my on board MPG CPU. I did reset the average MPG upon my first fill up and snapped this photo at the end of this MPG test, surprisingly it’s fairly accurate at 9.8 MPG.

• I didn’t fill the DEF full for the test, so I don’t know exactly how much DEF I’ve used.
• I didn’t notate my starting generator hours so all I have is an estimated run time.
• It’s nearly impossible to know the amount of fuel consumed by the generator unless you document every device run, including the watts, time run, etc while using the generator, but I’m not that patient.

Overall I’m pretty happy with the 9.62 MPG, especially considering our route and how Mother Nature didn’t help us out any! I wish there was a way to increase the MPG of an RV but other than a more streamlined and aerodynamic design, or maybe an electric hybrid RV, I’m not sure it’s going to get much better anytime in the near future.
Check back soon as I’ll be updating regularly throughout our trip.

03/2014 – 05/2014 Hills, Plenty of Flat and “Mountains”

This time we drove through the Hill Country of Texas, the higher elevation of Birmingham Alabama, and the Blue Ridge and Smokey Mountains of North Carolina and Tennessee. Needless to say there was some pretty big up and downs on this route so it’s interesting to see how these hills affected the Fuel Economy of our RV.
Same driving habits as before: 55mph, no a/c, towing a Smart car, etc. Fredericksburg, TX to Birmingham, AL to Boone, NC to Bardstown, KY

25.67 MPG Combined Fuel Economy

 

2014 Fleetwood Excursion 33D

14,998 Starting Mileage
17,047 Ending Mileage
2049 Miles Driven
202.73 Gallons of Diesel Used
$758.22 Cost of Diesel Fuel
$31 ½ tank of DEF – approx. 6 gallons
10.11 MPG Sub-Total
7.2 Hours of Generator Use (78.5 -85.7)
3.6 Gallons of Generator Diesel Consumed (approx)

10.29 MPG for the Fleetwood Excursion based on my second fuel economy test

As you can see in the photos the trip computer wasn’t too far off from our actual mileage, but it was still a little more positive than reality (granted it’s much better than the Trip Computer on Windy the RV)

To add a little fun to the total MPG of our RV we’ve also logged the fuel economy of our Smart Car. Realistically we should be combining the MPG of these two for our overall trip fuel economy…after all we purchased the Smart car specifically to tow behind the RV so we could easily explore the adventures waiting outside of the campground. It’s only fair to combine the number right?

2009 Smart Car ForTwo

30,566 Starting Mileage
32,037 Ending Mileage
1,471 Smart Car Miles Driven
35.83 Gallons of Premium Gasoline Used
$137.78 Cost of Gasoline

41.05 MPG for the Smart ForTwo Convertible

 

What’s most interesting is the RV industry is not required to deliver any sort of EPA regulated numbers, you know: like a car!

So when you ask your RV salesman “what kind of Miles Per Gallon does this RV get?” when he answers it’s most likely a big fat guess…or worse…a bold faced lie. In my opinion this is one of the major downfalls to the RV industry; but leave it to bloggers, writers and forums to test, document, and report on their real RV MPG. A little searching online and hopefully you can find some real world Fuel Economy on the RV of your dreams.

Share your RV Make, Model and MPG below in the comments; let’s make it a little easier for people to find this valuable information. If you don’t have an RV tell us which one you’re interested in and maybe we can help with finding the MPG for you. If your 40 footer really gets 16 MPG please tell us how you do it 🙂

Disclaimer: We were not compensated for this post and as usual our comments, data and math skills are all based on our experience with our Fleetwood Excursion and the RV industry as a whole.