Tow Vehical MPG...

rcarlson1957

kottum good point on keeping the air stream clean. I have the hard folding factory cover and no rack or anything to mess with air flow front to back. I've thought about getting a inflatable tandem kayak or canoe but if we do, I'm store in directly behind the truck back window to insure it doesn't interrupt the air flow. We normally limit to 65mph on major roads and 55mph on secondary roads. Love the the paddle shifters in sequential mode in the mountains. Smooth reliable and very comfortable truck that pulls a 320 great. And that trunk in the bed is the bomb. 

CharlieRN

ScottG said:

My 4.0L V6 Nissan Frontier drops from ~20 MPG to ~15 MPG.

This topic comes up from time to time. ~15 MPG seems to be the sweet spot. Smaller vehicles with higher initial MPG seem to take a bigger hit when towing, so everyone lands in about the same place.

Yeah, this.

The mileage with my Telluride (3.8L V6) is very similar to that of @ScottG with his Frontier. The Telly gets roughly 21 mpg on the highway; towing our 320 decreases that to about 15-16 mpg depending on terrain.

marchule

For a 520 mile round trip with lots of mountain passes (in Utah) averaged 16.6 mpg.  On one leg of the trip with a strong tail wind I even got 20.1 mpg.  This is with a 3.8L V6 2022 Kia Telluride pulling a 400BD.

CharlieRN

I've often wondered if you could increase your mileage (or range if you prefer to look at it that way) by shaping the airflow with spoilers placed at the rear of the TV. You often see such devices on the roof of the cabs of tractor-trailers. This seems like something that would be relatively easy to do if the TV was an SUV with roof racks - at least for the flow over the top. I'd think you'd also want to do something similar for the sides, and that may be more difficult since you don't have convenient mounting points.

Another place that would benefit from improved airflow is the rear of the camper. This is something that you again in see in the trucking world, where movable shields are installed at the rear of the trailer. Unlike a trailer with squared-off rear, our T@B rears have some taper, which I'd think helps a bit, but a small rear spoiler may provide a marginal improvement.

While I've seen some concept trailers that are supposed to be streamlined, the Canadian company Safari Condo has been offering one for some time, the A2124 camper (drawing below). The camper is roughly the same size as the 400, but because of the design, offers less interior space and is also more costly. I don't know how efficient the A2124 is but it seems to be popular among Tesla owners who presumably are purchasing it because of its aero properties.

bigsnout7

We have an Audi Q5 TDI Diesel towing a 2022 TAB 400 Boondock. Our first trip from Dallas home to Denver we averaged just under 18 mpg traveling between 70-75 miles and hour. I actually enjoy the game of trying to eek out as much mileage as possible as I drive. BTW the VW/Audi diesels are amazing engines and much sought after for their power, efficiency, and reliability. 

Binghi

Only problem being they got outlawed for emissions fraud. I would have bought one but for that problem.

Jpvert

SO far im doing 17-18 mpg with my Rav4

tomwasser

I get about 70 mpg equivalent with my VW ID4 2021; maybe a little more on flat roads in the summer pulling my Tab S 2023

ClaudeA

Between 18 to 21 US mpg depending mostly on wind, hills, flat, with a 2022 Toyota Sienna Hybrid towing a 2016 320 outside kitchen model

Dragonfly4100

ClaudeA said:

Between 18 to 21 US mpg depending mostly on wind, hills, flat, with a 2022 Toyota Sienna Hybrid towing a 2016 320 outside kitchen model

Claude, is your Sienna an AWD model? I have been thinking of purchasing a new Sienna Hybrid for a TV and for general road trips for the fuel economy and capacity but right now our 2022 4Runner is only getting around 14 MPG towing our 2018 T@B CS-S. 
Tom

HedCount

just got back from a 380 mile trip over the mountains and back.  Towing with a 2001 F150 4.6 liter V8.   We averaged 12.5 mpg towing a 2023 TAB 400.   The truck usually gets 14-15 mpg empty so I figure its a win

ClaudeA

@Dragonsdofly Our Sienna is not AWD but I think the AWD model gets close to the same fuel economy. We just returned from a few days of camping and on a 100 mile trip but only going about 55 to 60 mph we got 21.5 mpg US(no wind). Trouble is they are very hard to get one. Toyota is way behind on filling orders. All in all it's the best all around tow vehicle we've owned.

Pretzel14

2022 320s Boondock and 2021 Toyota Highlander Hybrid

Flatland I get 22-25 mpg and WV, Smokies, Badlands, Black Hills all ranged 18-19 mpg.

sequimite

2016 320 S towed by a 2015 Mercedes-Benz GLK 250 (diesel). 23 mpg on our first long-ish trip of about 500 miles traversing 4 Cascade mountain passes (Snoqualmie Pass and Blewett Pass both directions) rarely breaking 60 mph. We currently have boxes on the boondock platform that are probably very aerodynamically dirty. I could see making 25 mpg with different boxes.

kottum

I love turbo-diesel torque for towing, and the fuel economy that gas turbos cannot do.  Only thing is, you have to factor in the higher price of diesel fuel and maintenance for actual economy.  Electric will be similar if/when they sort out the relatively short range issue; as is electrics can be considered commuter cars.

sequimite

Yep, more expensive fuel, and quite expensive maintenance. It's a trade-off.

MuttonChops

kottum said:
I love turbo-diesel torque for towing, and the fuel economy that gas turbos cannot do.  Only thing is, you have to factor in the higher price of diesel fuel and maintenance for actual economy.

Hear You.
Back in 2000 before I was travel trailer traveling, I purchased a VW Jetta Diesel (manual tranny).  Part of the before purchase justification for the higher cost engine was diesel fuel sold for a few cents less that gasoline.  {that was also before VW started gaming the EPA tests}

That fuel cost difference of course reversed within a few months of owning the diesel.  I've never understood how diesel was cheaper than gasoline for decades and decades and then one day it cost more than premium octane gasoline? ! ?

Since diesel provides more BTU of energy (why there is better MPG) one would think that it would have always been  more expensive than gasoline . . .

Due to purchase & operating costs the VW was my one and only diesel powered land vehicle . . . and even now the driving experience is remembered and missed - - - - talk about FUN to drive torque - - -

Side Note:
In the early 1900's steam engine powered launches used gasoline instead of water to generate the 'steam'.   Can you image today letting your kids play on the lake with a boat that has an open wood fire heating gasoline - - - -.  Yet, that was common and state-of-the-art at the time.

kottum

MuttonChops, we still have the 2006 Jetta TDI manual shift we bought new.  Loved the car and still do, it runs and looks like new with 100,000 miles. Handles like a sports car. Only about 300,000 more miles to wear it out.  Another bonus of diesel fuel, diesel is oil and it lubes the cylinder walls as it runs down the road.

I will say it hates biodiesel nearly as much as our gas engines hate ethanol.  We can thank corporate farms buying out politicians for that.

MuttonChops

kottum said:
. . . it hates biodiesel nearly as much as our gas engines hate ethanol. 

I ran 10-20% biodiesel (well above VW recommendation) for many years in the 2000 VW.
There was a slight decrease in MPG . . . but what's the issue of 1-2 MPG loss when highway driving was getting 55-MPG on pure dino . . . . there was no noticeable driving performance difference with biodiesel.

In my bigger diesel engine boat I ran up to 50% biodiesel with no issues.  That boat was a dry stack . . . and the exhaust smelled wonderful at 50% bio - - - - made one hungry - - -

kottum

VW manufacturer hated biodiesel, maybe because of poorer lubrication. Not sure. I hated biodiesel when my 1998 Jetta TDI induction system clogged with soot in a cold Minnesota 20-30 below winter. Dealership pulled the intake manifold and picked away at it to clean it.  So clogged the engine would barely accelerate.  My 2006 TDI runs poorly at low rpm with it.  Chrysler said avoid it, especially above 10% on our 2016 Ram EcoDiesel.  Both VW and Ram have threatened warranty coverage using higher concentrations of biodiesel.

I think the EGR system is where the problem lies.  Routing that sooty exhaust back through the intercooler, turbo, and intake manifold coats the whole system with soot, especially in cold climates.  Dealer told me the biodiesel causes more soot to accumulate.  There are ECM tunes to cut off the EGR routing, but they are illegal, and the dealer will often erase the tune when servicing the vehicle.

irvingj

And I still have my 2005 TDI Wagon. It has the BEW engine, using additional camshaft lobes to drive each cylinder's injector. VW only made the engine from about 2003+ until 2005.5 model years -- this was before the "cheater" BRM engine. It tolerates but doesn't like biodiesel. (VW says "no more than 10%".)

We used this to pull our 2004 DM T@B, and it did so surprisingly well,  after I figured out that the T@B, being so much wider and taller than the Jetta, became a parachute above 55 or so mph. Trying to maintain highway speeds, mileage dropped from 48 to 18 (!!), but once I slowed down to <60mph using "back roads," it went back up to 32. Not bad.

We sold out T@B (still miss it) and now have a 2015 Sprinter-based Roadtrek RV. Its diesel engine is amazingly complex --mostly due to emission controls-- and servicing it is definitely above my pay grade now, so expensive dealer visits are the rule, GRRRR. I don't believe I'll ever buy another diesel.

My 2005 Jetta Wagon, OTOH, I'll probably never sell. Now has only 170K miles; I do my own work on it.

BTW, our Roadtrek SS Agile (short/tall Sprinter, 3.0L OM642 engine) averages about 20 mpg -- not bad for 8,000+ pounds, but not like the Jetta/T@B combo (sigh)....

kottum

Okay Irving, now you've got me thinking about getting a custom hitch on our 2006 Jetta TDI, manual trans. Ours has the cam-driven injectors as well, much simpler engine than the later ones.

I also love this little car and neither of us would ever let it go.  These have the zinc-dipped body and a relatively simple diesel engine that will be impossible for us to wear out.  Plus terrific and reliable mpg against the wind or through the mountains with turbo-diesel torque. 

In the larger picture, that is real economy.

irvingj

A trailer hitch ("Hidden Hitch" brand) was one of the first things I got for my 05 wagon. I still use it quite a lot, for a 14' boat or a 4x8 utility trailer. With the trailer attached, I call it "my baby diesel pick-up." I remove & clean the EGR about every 10K miles. You have a 6th gear, right? Sure wish I did!

BridgerSunset

Another data point, possibly unique, for the archive:

6.6 liter diesel Silverado 3500HD (previously owned a 5th wheel).
5,000 mile roundtrip last month with 400 boondock, Montana to Virginia & back.
2 humans, 1 large dog, limited gear in the box.  Minimal fluids in T@B.  Speed generally 60-70 mph across I-90, I-80, I-70.  Some opposing weather going, calm upon return.

Overall result:  13.5 mpg

Normally 18 or so @ our elevation& town/country speeds.

ybakos

15mpg in my Honda Ridgeline towing a 2022 Boondock CS-S, full water tank. Driving about 55 - 70mph, varied terrain (up and down hills).