Auxiliary Gas Tank Build

Hey guys!

I've commented in a couple threads, and on the TW Facebook page about my spare tire gas tank project. Decided to start a dedicated thread so those of you who've shown an interest can follow my progress. Feel free to pitch in ideas, constructive criticism is appreciated!

After researching all the commercial options, I ran into two major issues. First was the price. $1200-1500 just for the tank, plus another $500-1000 for shipping/labor/bull$#!*. Second issue I had was the designs of the available aftermarket tanks. One of them expands the existing tank right over the exhaust piping (umm, no thanks!). Finally was the change in fuel capacity. Best total from commercial tanks was about 35 gallons, which isn't quite the extended range I wanted.

So.... I opted to make my own, and do it better.

Project goals...
1) Add 20+ gallons of total fuel capacity (success!)
2) Allow for transfer of fuel to the main (stock) tank without getting out of the cab (pending)
3) Maintain ground clearance & departure angle (pending)
4) Do not cut, drill, weld, or otherwise modify the frame (pending)
5) Spend less than the base cost of the cheapest commercial option (roughly $1200) (pending)

Due to the number of comments, I would like to clarify that there WILL be baffles in the tank!

Parts & Costs HERE

5 JUNE
Visited my local sheet metal shop. After explaining what I was wanting to do, I was rejected do to "insurance reasons", but was given a phone number of a local welder that runs a shop out of his garage. Called him, then met up and discussed my idea. He decided to give it a try, so we spent an hour or two brainstorming under the back of my truck.









11 JUNE
Met with the guy who's welding up the tank today. Had a cardboard mock-up just to check the spacing and general shape.
Original plan was a 22"L x 20"W tank, 10" deep in the front, and 8" deep in the back. This worked out to about 17 gallons (not quite hitting Goal #1). After the cardboard test-fit, we expanded it to 28"L, and kept the same upward slope on the bottom of the tank. Rough math now works out to nearly 22 gallons!

I will add pictures tomorrow to show the general ideas about placement and layout of everything.

I have all the fittings, pump, filter, etc on order. Should arrive in a week or so. Tank built hopefully by the end of the month, but my welder runs his business out of his garage and he's constantly busy.

12 JUNE
Well I seem to have developed insomnia tonight, but I can't do any real work at the moment, so I sketched out the tank design and location for reference. I'm not a draftsman, so please forgive my mediocre penmanship!

 

ROUGH COST LAYOUT
Labor................................$???.??
Sheet metal for tank............$75.00
Fuel pump..........................$86.99 (Carter, P4070)
Fuel filter............................$53.99 (JAZ Products, 547-836-001-11)
10ft of 3/8" fuel hose...........$25.00
"Big Red Switch"...................$4.00
Rollover vent.......................$31.99 (JAZ Products, 547-834-006-11)
Tank fill valve.....................$111.99 (JAZ Products, 547-345-250-03)
Fill valve mounting plate........$35.99 (JAZ Products, 547-315-030-03)
Remote fill nozzle..................$96.99 (JAZ Products, 547-350-250-03)
Fuel filler housing..................$13.13 (Rampage, 594-7508)
TOTAL................................$535.07

 

subd

 

The only thing I would point out is that you might want to consider the possibility of an explosion and fire from a rear end collision when putting it where you suggest. The tank would easily be pushed into the rear Differential and rupture or just rupture from the impact. Also I see there are no baffles included in the drawing. You might want to think about that so as not to have the gas slushing around while driving.

 

Did you say..... Pinto?

 

Same place as where the wrangler and land rover discovery has theirs. they may break down all of the time, but there aren't mass amounts of vehicle fires when they get rear ended.

 

Good idea for sure. Suggestions:
1. Consider making the tank out of aluminum. (Steel tanks rust FAST on the inside, and you have no way to protect the INSIDE once it gets welded up)
2. Baffles on inside (as mentioned)
3. Rollover flapper (just in case of a problem, you won't have gas leaking out all over the place. Very dangerous)

 

Always happy to see someone doing something different. Keep up the good work!

If you are going to stick with steel for your tank you will want to line it. Check out this thread for more information on the product and application.

 

Thanks for the suggestion! Something like this, perhaps?

http://damonq.com/red-kote.html

 

That one appears to be intended for older tanks, you'll want to talk to the manufacturer about using it on new steel. It should work though.

 

Another good suggestion! I really wanted to do aluminum, but it's so hard to find people willing to weld that stuff for a decent price!

If this project turns out as well as I hope, and there's interest in a group buy, I might look into an aluminum version. Sure would save a few pounds!

 

Things to consider for your fuel cell.

Make it out of aluminum. It will bend rather than fracture/crack/break unlike steel.
Baffles are a wonderful thing. Helps prevent sloshing which should keep your turns a little smoother.
Install Sea foam into the tank. (You will need an external pump for this). Sea foam will help keep the slosh down.
Have the tank lined on the inside. This way it will not or should not leak if you are hit.
Lastly. Venting the cell. Credit goes to those on Pirate4x4 for this. Page 2 has some diagrams.
http://www.pirate4x4.com/forum/general-4x4-discussion/837433-fire-safty-fuel-cell-2.html

Good luck on the build.

Bacon

 

This is high on my list for future mods on my truck.

I'm sure you considered the aux tank From a 1985 ford F150. In your view why not go with that tank?

 

Subd. Keep up the good ideas flowing.

 

I mean its cool and all... but 3-4 5 gallon cans strapped down in the bed leaves A LOT of money left over to fill said 5 gallon cans.

 

I've thought of this, however I sleep in the bed of my truck under the camper shell. It's also a fun project. I like the idea of not having to unload and individually fill 4 gas cans and then individually add them to my gas tank. I have thought of putting the cans on a hitch mounted cargo basket as well. For the short term this might be okay, but for long long trips with a lot of off road I don't see it being viable. Also anything above my roof line kills what few Mpgs I get.

 

Interesting stuff. Looking forward to seeing how it goes.

 

Subbed

 

Keep us posted.... i am sure this post will inspire others to build.

 

That tank is roughly 35"W x 28"L. It wouldn't fit under the bed without cutting off the spare tire supports. One of my major goals is to NOT permanently modify the frame.

Certainly would be cheaper. But I use my truck bed a LOT, and having to relocate gas cans every time I want to haul something would be a pain in the butt. Plus, with a transfer tank, I refill my existing tank with a flip of a switch, and I can do it without stopping and getting out of my truck. I already carry three 6-gallon water jugs in the bed, so more jugs is... well, more jugs.

All personal preference I guess. For me, the cost-benefit decision was to build the tank. Besides, I love a good project, and the chance to do something new.