Looking for a cheap Auxiliary Fuel Tank solution

Tom P · Nov 17, 2017

Supercharged111 said:
Is gravity feed still illegal with a shutoff? I forget. My intent is just that. Also to ensure the vent is shared with the main tank.

That is a good question. I suppose if it didn't look suspicious, then you would probably never have to worry about it. We don't have vehicle inspections here so the only way the authorities would ever see one is if my truck was impounded, or at the least, some DOT cop with a chip on his shoulder, but they usually don't bother trucks with RV's.

Christian Steffen · Nov 17, 2017

I would be shocked if anyone in a pickup got hassled for how they added fuel capacity. As long as it's safe, I wouldn't worry about it. Just my opinion anyway.

I too have thought about adding a gravity feed reserve to add range. 25 gallons doesn't get a big block far haha

Tom P · Nov 18, 2017

Christian Steffen said:
25 gallons doesn't get a big block far haha

No kidding. My OBDII scanner can estimate my fuel economy and right now it says I'm averaging 5.1mpg. Granted my trips to work are short and when I hook the scanner up and drive with it, I'm usually testing "throttle response". Towing this summer with my 28" travel trailer I calculated around 7 mpg so that put my range at around 150 miles per tank. Hopefully, I still have a gremlin hidden somewhere that is causing me power loss and and poor fuel economy. I'd really appreciate 10mpg towing next summer. Digging into what I think is a fuel pump problem today. Hoping its just a ground or bad wire.

Christian Steffen · Nov 18, 2017

Tom P said:
No kidding. My OBDII scanner can estimate my fuel economy and right now it says I'm averaging 5.1mpg. Granted my trips to work are short and when I hook the scanner up and drive with it, I'm usually testing "throttle response". Towing this summer with my 28" travel trailer I calculated around 7 mpg so that put my range at around 150 miles per tank. Hopefully, I still have a gremlin hidden somewhere that is causing me power loss and and poor fuel economy. I'd really appreciate 10mpg towing next summer. Digging into what I think is a fuel pump problem today. Hoping its just a ground or bad wire.

What does the trailer weigh? 10 might be a bit optimistic depending on the terrain but maybe 8 or 9 is achievable. When were talking numbers that low, even 1 mpg is a pretty big deal.

df2x4 · Nov 18, 2017

Dear lord... I never realized the mileage from the 454s was so bad! The carb'd 400 SBC in my Monte has been averaging 10.5MPG or so since the last rebuild. You guys have got it rough!

Tom P · Nov 18, 2017

Dry weight on the trailer is ~4500 lbs but that was taken in 1994 before decades of use. They absorb moisture and I know my trailer has dry rot which adds weight. Not to mention, they vinyl floor was replaced with laminate. Ive never weighed it, but when my brother in law pulled it to our campsite on that trip while my truck was being towed, he said it felt similar to his 2014 aspen trail which has a slide. On that trip we were loaded with 10 days worth of bottled water, juice, food and beer of course. We pretty much have to bring everything with us. Bikes, trikes, kiddy pool, strollers etc...

Tom P · Nov 18, 2017

df2x4 said:
Dear lord... I never realized the mileage from the 454s was so bad! The carb'd 400 SBC in my Monte has been averaging 10.5MPG or so since the last rebuild. You guys have got it rough!

Unloaded, when my truck was running well, I got around 10mpg on a day of pure highway driving.

df2x4 · Nov 18, 2017

Tom P said:
Unloaded, when my truck was running well, I got around 10mpg on a day of pure highway driving.

Ah that's not so bad then. I just saw that 5.1 that you posted earlier and my eyes about popped out of my head!

Christian Steffen · Nov 18, 2017

Oh if its only around 5k lbs then you might get into the 10s, I was imagining around 10k lbs. In bone stock form my truck used to get around 8 (maybe a bit more, been awhile) pulling a 10-12k trailer at 70 mph. This was usually on flat-ish ground with a few decent size hills. The worst we experienced was pulling a hill into the big horns outside of buffalo, wy. Its like a 20 mile pull that is mostly 6-7% grade, I bet we burned almost 10 gallons of gas haha

I really don't have any good mileage data while pulling on my current setup, but I average 12.5-13 dailying it and have gotten close to 15 cruising at 70.

BowtieBrody · Nov 18, 2017

Christian Steffen said:
Oh if its only around 5k lbs then you might get into the 10s, I was imagining around 10k lbs. In bone stock form my truck used to get around 8 (maybe a bit more, been awhile) pulling a 10-12k trailer at 70 mph. This was usually on flat-ish ground with a few decent size hills. The worst we experienced was pulling a hill into the big horns outside of buffalo, wy. Its like a 20 mile pull that is mostly 6-7% grade, I bet we burned almost 10 gallons of gas haha

I really don't have any good mileage data while pulling on my current setup, but I average 12.5-13 dailying it and have gotten close to 15 cruising at 70.

Last time I did the calculations, my trucks averaged 13 to almost 13.5 with the cruise set at 55, mainly open country driving, and on the day I brought home I managed to get about 14 with the CC set at 70;

My dad's C3500 gets 10 regardless.

Looking for a cheap Auxiliary Fuel Tank solution

Tom P

I'm Awesome

Christian Steffen

I'm Awesome

Tom P

I'm Awesome

Christian Steffen

I'm Awesome

df2x4

4L60E Destroyer

Tom P

I'm Awesome

Tom P

I'm Awesome

df2x4

4L60E Destroyer

Christian Steffen

I'm Awesome

BowtieBrody

Jesus Murphy!

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