Range when towing

So after our first 450+ mile round trip pulling the camper I found the range is pretty poor as I expected. We are planning a trip to either Texas or Colorado next summer (around 2700 miles round trip) as well as a trip to Florida in the fall (2500 miles round trip)
I’m considering two paths for adding fuel.
1st is a 15 gallon cylindrical tank meant to be mounted on landscaping trailers. My plan would be to have a unistrut or 80/20 rack in the driver side front corner of the bed for this tank. Adding a pair of 12 volt solenoids ( a 1/4 on the cap for vent, and a 1/2 inch on the output for the drain.) I would have a quick disconnect braided stainless line which would tee into the main fill nozzle to the tank. A switch near the steering wheel would allow gravity feed into the main once the main is below 1/4 full. This unit would be removable as I would only utilize it when towing long distances.

option two would be another tank with a pump in the spot the spare tire fits. It would be plumbed into the fuel feed to the engine. I’m guessing I could find a 18-21 gallon tank from a random vehicle to fit in there. This tank wouldn’t have a sending unit, so I would t know the fuel level. I would drain this tank first, and then when the engine starts to sputter switch to the main. And continue on as normal. Figuring out where to put the fill spout would be interesting. Ive seen a gent with an avalanche who did something similar to this, and he had both tanks filler necks in the stock fuel door. He made a new mount plate so he could fill either from that one location. the spare tire would sit in the bed which would be a pain.

Thoughts? Anyone done anything like this?

 

Since you asked, I’ll chime in and say just keep it simple and stay OEM. With so many gas stations conveniently located, why bother with an extra tank? Usually, one needs to stop for the restroom or grab a bite before the gas runs dry.

Disregard the above if you are way out in Wilderness towing.

 

Yeah, I could see both sides of the argument. Leave it stock, stop more often to get gas or check the rig. Or, add a tank for convenience. I would feel better adding a tank under the truck inside the frame, like you mentioned. It just seems safer..

 

When towing at 7.5-8.5 mpg that’s a usable range of 150-190 miles. In the past we would typically do 250+ miles between stops. This will add around 6-7 stops to theses trips. A not insignificant amount at 15-20 minutes per stop.

 

Thats awful MPG. Usually, I’m 10-11MPG on long trips at worst. Sometimes 13MPG depending on load. These are highway miles.

Turd Gen Section has plenty of ‘Bigger Gas Tank’ Threads for ideas.

 

Yes it is pretty poor, 3rd gen has aftermarket support. I haven’t found anything that is bolt in for our trucks.

 

Here is the mileage I saw

Mileage based on

$140 ScanGauge - SG2 II Ultra Compact 3-in-1 Automotive Computer with Customizable Real-Time Fuel Economy Digital Gauges , Black , 5"

scan gauge over 10 miles of relatively flat and relatively steady speed.
71 mph - 7.4mpg
68 mph - 8.2mpg
64 mph - 8.6mpg
60 mph - 8.9mpg

on my first tank at pretty steady 70, I got 7.5 mpg and 165 miles before the low fuel light came on. Running 60-65 offers a more reasonable 8.5, which is what i ran on the way home, but still had to make a stop on the 230 mile drive.

 

I can’t recall anyone in 1st Gen doing an auxiliary gas tank mod. I’m sure its doable. Spare tire location sounds best.

 

You said that you tow but exactly what do you tow?

 

A travel trailer. Kz escape 231bh

 

Yeah. You are pulling a very large wind catch. Might need a bigger truck.

 

Found these articles...

https://www.tundratalk.net/threads/aux-in-bed-fuel-tank-install.162353/

It's for a 2nd gen, but this was very interesting. I'm sure it could be engineered with the right skill set and patience..
https://forum.ih8mud.com/threads/replacing-the-tundra-26-gallon-tank-with-oe-38-gallon-tank.1101251/

 

Pulls it well, just drinks fuel. My uncle recently got a similar trailer, 25 foot rather than 23 and he’s seeing similar mileage in his 2018 Tahoe. He’s also grouchy with the range. I’m thinking with something like this behind me no matter what I drive I can expect under 9 mpg. I just want another 12-20 gallons of fuel.

 

How much does that rig weigh (approx.) when you are towing?
Include water, food, ice, toy, gear etc.

 

The gvw is 5000lbs. 3950 dry.

 

I wonder if there are gains to be had with a camper shell to streamline airflow.

Maybe a re-gear or performance mods. PHM has 12-hole injectors on his truck.

 

a couple things.

1: unless you’ve corrected the mpg readings on the scan gauge to your truck, they’re probably not accurate. I’d double check with the odometer.

2. I’d think for a permanent solution, under the bed would be best. I know the 1980s and 1990s Ford pickups used dual tanks and a selector valve to choose between them, this also made the fuel gauge read from the selected tank.

another, simpler way to do it would be to set up a simple electric pump to go from the aux tank to the main tank. When the main tank is down to about 1/4, you flip a switch to fill it back up, that way you don’t need to mess with any of the factory wiring.

just my two cents.

 

I don’t think regearing is going to make a difference in fuel economy. Debatable with performance mods, but they certainly aren’t going to offset the cost of themeselves.

 

1. I have corrected it.
2. Those are the tanks I was looking at. I was considering. That simpler method.
The only concern is I would then have the spare in my bed.
I just found this on Amazon. 10 gallons would be ok, 80 more miles. comes with a solenoid. Lightweight, and fits over the wheel well and in the front corner out of the way.
however it’s for water methanol, so I’m not sure it would hold up to gasoline.

 

I second that.

Frequent stops and jerry cans in the bed for dry spots or emergencies.

 

We towed thousands of miles with our 4runner. It had a useable range of about 100 miles before looking for a fill up. I added a 5 gallon can on the trailer tongue. I like to stop and pee and run a lap around the parking g lot. Th 5 gallon can allowed some stops to happen at rest stops or just some random lot. It kind of changes the pace when you stop for you and not because it's where the fuel is. I'm looking forward to the extended range of the tundra. A towing range of around 400+ miles would be nice and it would really help change the pace of the trip. Towing a giant square box around at 70 is pretty much always going to result in 10mpg or worse. Round trailers do get better mpg but does 11mpg instead of 10 matter that much?

 

Some of these solutions seem very elaborate and involved. Hows about a few gas cans in the bed of the truck and an old fashioned funnel. Pull over when needed and fill up by hand. Total cost for the equipment is about $12.

 

Agree with x-tra can in bed, I've always carried x-tra 2.5 gal can in summer and short trips , if not for me just if someone else needed a couple gals. Bought a tall narrow plastic 5 gal. for longer trips, gives me x-tra 7.5 gals.

 

I average around 9 mpg when towing. So range sucks. I typically put about 5000 lbs behind the Tundra to achieve these results.

 

I have the exact same truck, 1st Gen double cab. Towing a 3500 pound flatbed (much less wind drag) I get about 280-300 miles before I fill back up (I don’t usually let it go below a quarter tank). That flatbed is wider and taller than the truck (with the load on it). Mpg is around 9-11 depending on speed.

on the contrary, pulling a chalet camp trailer (the hard sided A-frame) I get close to 12-13. Trailer is same width as the truck and shorter, so the wind goes right around it. I can make it close to 350 miles on a tank this way.

both of these are towing near the speed limit (60-65-70 mph) with a good load in the bed and three passengers. Likely a tad overweight to be honest. Also running premium (92 octane) gas.

With my experience, the more wind drag you have(this is increased by both the size of your load and the speed you go, combine the two and fuel mileage goes south FAST) the less mileage you will get and the harder it is to keep speed. You just can’t escape the laws of physics. The more wind drag you have the harder it is to pull, and the more fuel your truck will burn.

Don’t be surprised if my math is wrong with my fuel mileage calculations too.

nice setup! I like it. Looks real good behind your truck. Every time I see a Gen 1 towing I smile, I don’t see them too often!

 

I have a camper shell. Towing my A-frame chalet and flatbed trailer, I don’t notice a difference. I haven’t towed too far without the shell on so my experience is limited but the 1 mpg difference in the shell isn’t worth the cost in my opinion.

if I was to get a different shell right now, I’d get one of those sod toppers. Cheaper than hard shell and just as weathertight. Plus you can remove it yourself. Super super cool design.

 

@Professional Hand Model do they (not exactly sure the company) make bigger injectors for vvti trucks? Do they have adverse effects with the transmission shifting? (like adding power via tuner to a diesel pickup, bye bye tranny)

also, cost. How much are they if you don’t mind sharing??

 

Best person to discuss this topic is Keith at Dirty Deeds, but from the little I know the vvti has a greater cc capacity. The vvti and the non-vvti have different cc capacities. Price ranges in the mid $300’s depending.

My experience is the transmission holds the low gears a little longer on acceleration. On deceleration, that lazy downshift when coming from speed down to slow into a turn is no longer present. The gear is there when you go to accelerate. No better or worse on MPG.

I believe the effects from the injectors happen at the throttle body sensor which send the signal to the transmission. Thats where the magic happens. The transmission isn’t overtaxed, but just reacts in a better way.

 

Last year I drove this brand new Sequoia with this embarrassingly tiny u-haul across the country to deliver the truck and some furniture to a client in Montana.

With no fixed speed limits in Wyoming and Montana for much of the journey along with up to 80 mph headwinds and much terrible blizzarding and way too many crazy ass fellow drivers seemingly in competition the rest of the way it was tough to keep the speed I wanted to and do much better than 7-8 mpg much of the way!
I was more than a little surprised too and kept experimenting trying to get improved mileage as I went.

Unless I stayed at 70 or under and there was no little wind or snow I just could not break 12 or so when driving at Elevation too.

The minute I arrived at the u-haul store in Bozeman and lost the trailer I was back in business though!
I was the most shocked that the tiny trailer could have that much influence over the Sequoia and the 5.7 but the numbers did not lie.

 

280 miles with a quarter tank left??? that's my normal non-towing MPG. That's like 15.5mpg or so. No way you're towing 3500# and getting that kind of range. Unless you have a giant fuel tank and not the factory 25 gallon one I have. What's the secret here?