MPG/Range question specifically for those who pull a trailer

[Martinjmpr]

Wife and I just got back from a great 5,000+ mile 2 week trip that took us about 2/3 of the way across the US and back. 13 states and 1 Canadian province. We left from Denver and went North to South Dakota, North Dakota, across North Dakota through Minnesota, upper Wisconsin and Upper Michigan, then into Ontario, past Toronto and over to Niagara Falls, down past NYC and then back West on I-80 through PA, OH, IN, IL, IA and NE.

We were pulling our new T@B clamshell trailer. By the book it weighs around 1700 but I'm guessing with all our stuff on board probably close to 2000lbs. Well within the V6 4runner's 5,000lb tow rating.

Everything went pretty well but my MPG was atrocious. Horrible. Really the worst I've experienced. My highest recorded MPG was around 13 and lowest around 10.

So I'm wondering, from those of you who tow a 1-ton trailer on a regular basis, if this is just what I need to expect? When we had a 1,000lb trailer I could regularly pull 15 MPG. This trailer is not only heavier, but it's quite a bit higher than the top of the 4runner.

And understand (before anyone says it ) yes, I know a 4runner is not a Prius and I don't expect 50mpg. The issue I have is that while the 23 gallon tank is more than adequate for a vehicle that gets 16 - 20 MPG (as the 4runner is rated, obviously non-towing), for a vehicle getting 10-13, that 23 gallon tank goes fast. I was stopping roughly every 200 - 225 miles which is a lot more frequently than I like to stop.

If it was a full-size truck it would get bad MPG but it would also have a correspondingly larger gas tank to deal with that.

So I'm putting this out there to ask what experiences others have while towing a trailer of this weight. Not necessarily what your MPG is (since there are so many ways to calculate that) but how often do you have to stop for gas? Don't know what else I could check but as far as I can tell everything on the truck is working fine.

Tow vehicle specifics are as follows: 2007 4runner, SR5, 4x4, V6. Currently about 136,000 miles on it. Has a mild (1") FJ Cruiser lift and running 265/70/17 tires on FJ Cruiser steel rims with BFG AT KO's that were new last year. For the last 1000 miles I generally kept it in 4th gear (as the manual recommends when towing) which didn't seem to affect MPG much (it was a solid 12 - 12.5) but it kept the transmission much cooler (I run a SGII and monitor transmission fluid temps.)

 

[blind squirrel]

I towed our 21 ft Malibu boat, roughly 2700 lbs, from Kansas to lake powell and averaged 9 mpgs by the meter on the car. Most folks on here say our digital read outs are wrong, but I didn't track the mileage myself. I think you are normal at your readings. Mine is a v8 though too.

 

[RPS13]

A pic would help, but I think you're experiencing aero drag. Weight has very little to do with MPG when towing at highway speeds. Your rolling friction goes up, but that's small potatoes compared to aero drag, especially with something larger than your 4Runner in frontal area, and really boxy.

I get about 13-15 mpg towing this @ ~4200-4400 lbs (~1800-1900 lb trailer, ~2400-2500 lb car). Way more weight than you, but the aero drag isn't that horrible, so it pulls fine in 4th, with occasional trips into 5th if I'll be going downhill for a bit.

And yes, that's too much tongue weight to illustrate what that looks like! Moved the car back about 8" and it really evened out.




But really, any gas engine car pulling a trailer with lots of aero drag will get horrid gas mileage.

 

[Martinjmpr]

A pic would help, but I think you're experiencing aero drag. Weight has very little to do with MPG when towing at highway speeds. Your rolling friction goes up, but that's small potatoes compared to aero drag, especially with something larger than your 4Runner in frontal area, and really boxy.

I get about 13-15 mpg towing this @ ~4200-4400 lbs (~1800-1900 lb trailer, ~2400-2500 lb car). Way more weight than you, but the aero drag isn't that horrible, so it pulls fine in 4th, with occasional trips into 5th if I'll be going downhill for a bit.

And yes, that's too much tongue weight to illustrate what that looks like! Moved the car back about 8" and it really evened out.




But really, any gas engine car pulling a trailer with lots of aero drag will get horrid gas mileage.

Thanks for the input. I had hoped that since our T@B has a "teardrop" profile the wind drag wouldn't be as bad as if I was pulling a big white box down the road.

Here's a photo of the rig for explanation:

Your comment about a gas engine car pulling a trailer with a lot of drag pretty much confirms what I thought: I don't think there's anything "wrong" with my setup nor do I think there's anything I can really do differently (though at least one person suggested an air deflector - which I might try, though we also carry kayaks so if we have the kayaks on, I can't use a deflector.)

Basically what this means to me is that when it comes time to replace the 4runner I will replace it with a full size truck. Honestly I don't mind the 12 MPG as much as I mind the 220 mile range. An Avalanche or Suburban would probably still give me 12mpg but the 31 gallon tank would give me a working range of over 300 miles between fuelups and would also provide a lot more space to carry stuff.

 

[CXS]

I just finished a 2 week trip too. Denver to the Grand Canyon (north and south rim) then Lake Powell for 2500+ miles. Mileage was lousy but it was 100+ degrees the whole time so I had the a/c running, 3500lbs trailer and V8. I pull a barn door so 9mpg's was fine.

 

[RPS13]

The teardrop probably doesn't help that much, as the divergence angle is too steep for the flow to be attached. In other words, the air sees it as basically a square shape of that height (roughly).

Anything steeper than this half-raindrop shape will cause flow separation (grey area), and thus create a lot of suction pressure on the back of the object. For the speeds we are travelling, the back of a vehicle is actually as much or more important than the front when it comes to aero drag due to this flow separation issue.

 

[G.I.G.]

Sorry to hear that you took such a big hit on MPG's while towing. My wife and I recently purchased a Livin' Lite Quicksilver XLP that weighs 1,500 lbs dry and will be taking it on our first road trip this holiday weekend. Wish us luck!....

I have a couple of observations. First, I've noticed that towing capacity and what is an ideal towing limit for a particular vehicle are not necessarily one in the same. My 4R has the V8 and a 7k lbs towing capacity, and I would never want to tow anything above 5k lbs with it. While the drivetrain and chassis might be capable of towing that much, I think you're really starting to push the limits of a mid-size SUV at that point, regardless of which engine you have. And like you mentioned, other gear (coolers, etc.) quickly add weight and therefore kill MPG's.

Wind resistance of course plays a factor as well. Since you were on a long road trip with a lot of highway driving, this probably played a major role in the hit to MPG's that you observed. I had considered a hard-sided camper when we first started looking, and you can find some nice ones weighing under 5k lbs. However, living in Colorado and driving in the mountains with the added wind resistance of a trailer that sits up higher than my 4R, I decided it would be best to stick with a popup due to both weight and wind resistance savings.

Unfortunately, what you gain in MPG's with the V6 around the city and not hauling gear, you sacrifice when towing. I suspect that I will get around the same MPG's as you when I head out this weekend. I'll let you know what my observations are.

I know that none of this directly answers your question regarding MPG performance and range. The gas tank in the 4th gens is the same size regardless of engine (V6 or V8) so I have the same size tank as you. I think our 4Runners are jacks of all trades, masters of none. They're great for cruising around town comfortably, doing some off-roading without the need for a ton of mods, and towing/hauling gear for us weekend warriors, but they don't excel at any one of those things alone. I still love my 4Runner and think it's perfect for my needs (daily driver, occasional off-roading, family/gear hauling) considering I only own one vehicle, but it is not the ideal towing vehicle. A slightly larger gas tank would have been nice. Other than keeping your 4Runner tuned up and serviced, I don't think there is much you can do to improve MPG's or range.

 

[having fun]

I drive a big rig and by what I see of your trailer isn't too bad on top for wind restrictions. Look at the trucks some time, you have close to the angle to the way the trucks air flow on top is. Now I can't tell by your picture but, if your trailer is wider than the 4unner is, that will make a difference there on aero restriction. Again look at a 18 Wheeler, there trucks are pretty much as wide as the trailer. Some have added flairs on the sides to make up the difference.

 

[wnelax04sr5]

i get about 15 mixed towing a utility trailer at approximately 3500 pounds

 

[MangoJucie]

Was thinking the same too

I was doing some research before I go in on the set up. Your post helped with the gas mileage I’m going to get thank you, I made an account just to post that I found an auxiliary tank made to fit in the spares spot,it adds 24 gallons so you can make less stops that’s what I’m going to end up doing because I was originally gonna have like 20 gallons in gas jugs but not only does that take up alot of my cargo space I’d have to stop to fill it anyways.just posted because I didn’t see anyone say it.

Tanks and Accessories for Toyota 5G 4Runner - 2010-2022

 

[AuSeeker]

I was doing some research before I go in on the set up. Your post helped with the gas mileage I’m going to get thank you, I made an account just to post that I found an auxiliary tank made to fit in the spares spot,it adds 24 gallons so you can make less stops that’s what I’m going to end up doing because I was originally gonna have like 20 gallons in gas jugs but not only does that take up alot of my cargo space I’d have to stop to fill it anyways.just posted because I didn’t see anyone say it.

Tanks and Accessories for Toyota 5G 4Runner - 2010-2022

Thanks for posting and welcome to the forum....BUT you have posted a 5th Gen gas tank in the 4th Gen forum section, for those interested here's a link to the 4th Gen gas tank.

Tanks and Accessories for Toyota 4G 4Runner - 2003-2009

Either tank is a bit pricey if you ask me at over $2000..but if you need and or want it, go for it!!

 

[gaber6]

2005 v6 with 225k miles .
I towed a 14 foot 2000lb dry camper trailer 3000lb loaded likely for the past 18 months.

16mpg on flat 40mph.
13mpg heading west 55 to 65 across the plains.
19mpg in the Rockies from Denver to Vegas. Lots of 20mph up hills and coasting down.

Keep the rpms below 1900 and the car is happy.