Increasing the capacity

[ORCoaster]

I would like to know if I can swap the 14 gallon tank from a pickup into my Rabbit and get the extra 4 gallons of fuel space.  Can it be done?  Is there anything that would cause problems?  My route is just about the limit of my fuel tank right now so I carry an extra gallon with me but I would rather just add the capacity to a tank underneath.  Packing two extra gallons for the colder weather and poor mileage will just add to the smell in the car and I rather not have it.

Anyone already do this change out?

[81 vw pu]

I have a 81 pu and a 81 4-door rabbit and the tanks are completely different. Not saying it can't be done but they are different shapes.

[CRSMP5]

way different..

also caddy is ~18 as when i had mine 17gal fill ups were common..

81-84 diesel westy bunny also have a ~12 gal tank.. again many 11 gal fill ups.. but say a jetta diesel is 10... no idea where the extra room comes from..

what you seek is one of the spare tire tanks... ~10 gal.. fills by filing stock tank.. fills via t added to stock neck..

now if you had a mk1 jetta.. i have a ~15 gal 2nd tank i could copy that sits behind the back seat... like a audi 4k.. add that to a westy tank you got ~27gal on a fill up.. back in the hayday i could run 700 miles with the ac on in my gasser..

[ORCoaster]

Well that just tears it now doesn't it?  I was hoping for better news but I guess it is start looking at Best Tanks or some place for the wheel well model.  But the throws the spare in the cargo area.  Or on the roof? 

I wonder if they make a small enough one that would go inside the wheel of the spare?  That might be about 6-7 extra gallons but the hook up would have to allow me to get to and use the spare if I needed to.  Which occurred just a month ago.

Thanks for the info and the tips.  Not sure what I will be doing on this just yet.  Time to go look at what they got. 

[maxfax]

A 55 gallon drum fits pretty nicely in the spare tire well of a MK1..  Kinda hard to close the hatch unless you cut it down though...    I made my WVO tank out of such and had the fill spout located behind the plate like the old GM products..  Fuel gauge and all..  IT worked rather slick...

[ORCoaster]

I think I will look into a 100 gallon tank I can put on two wheels and a hitch and just drag it around behind me.  At the rate I am using fuel that would last about 3 months.  Might take a substantial reduction in mpg for the first 50-60 gallons though.

[R.O.R-2.0]

I think I will look into a 100 gallon tank I can put on two wheels and a hitch and just drag it around behind me.  At the rate I am using fuel that would last about 3 months.  Might take a substantial reduction in mpg for the first 50-60 gallons though.

maybe i should look into building an aux tank for the tire well..

if its got enough demand, maybe i will build a few...

[81 vw pu]

My bently states that rabbits through 79 hold 11.9 us gals.
80-82 rabbit=10 us gals.
83 rabbit=11 us gals.
jettas =10.5 us gals.

Not sure if pre-80 rabbit tank will fit but that would give you an extra 1.9 gals.

[CRSMP5]

R.O.R-2.0 ive thought of making them per order.. same as my mk1 jetta tank i have and the 27 gal caddy tank...

what you wanna do is get a donut spare.. and then build it with the height to tuck that ontop of the one you make..

people spend 200+ on old stock spare tire tanks... there is demand... just people cheap

[R.O.R-2.0]

R.O.R-2.0 ive thought of making them per order.. same as my mk1 jetta tank i have and the 27 gal caddy tank...

what you wanna do is get a donut spare.. and then build it with the height to tuck that ontop of the one you make..

people spend 200+ on old stock spare tire tanks... there is demand... just people cheap

that would be IDEAL..

make it so you could stuff a space saver down on top of the tank, and still have everything fit!

[CRSMP5]

the worst part with spare tire tanks is the vent is never big enough for diesel.. takes forever to fill... so just idea if you do this.. make a center fill/cap which will also hold the spare in place.. then all you need is a line to feed into the return line of the main tank..

why return line.. you do not want the main tank draining into the spare tank on a hill.. use it as a way to fill the main tank..

that only works with center fill idea.. else it will fill via the main filler and feed the main tank that way..

the tanks originally had a T added to the rubber fill hose between neck and tank.. at the lowest point of sad spare tank.. then a small vent tube at the top of the tank to get  T into the original vent tube..

ive seen plastic and steel spare tanks.. and one of the 2 steel ones had a cap on it for filling.. so 3 designs total..

the jetta tank and caddy tank were both made of aluminum..

of them all the caddy tank is the most simple to build.. and by measurements.. was 27 gal.. LOL..

[R.O.R-2.0]

im thinking, that if a 55 gallon drum fits in a spare tire well, im gonna use part of one of those.. should be sturdy enough. probably going to weld in some internal baffling..

[CRSMP5]

i think he meant that it fits in back of bunny.. think its too big in diameter...

i know where 3 are.. a plastic and 2 steel ones... he does not know if he wanna get rid of them though.. so told him to discuss it with you when you chat on the conversion... 

[ORCoaster]

I think a 55 gallon drum is too big but what about one of the smaller drums?  A 30?  I seem to remember a smaller one someplace.  I think the idea of small flat tank under the doughnut spare is the most do able idea.  Maybe even two fill locations, the standard and one behind the plate would do well I think.  Then servo a delivery line to the main and returns and switch it when you hit 400 miles on the OEM tank and gauge the second as well.  And yes to baffles in the tank.  Not sure what amount of gallons you would get from that setup but if it allows me to make 550 miles that is better than pushing the car up to the pumps.  Ah yeah, came close to that one twice. 

Why did they drop the capacity of the Rabbits compared to the originals?  Seems like they should have increased it.  Perhaps they decided that since the car gets such good mileage they didn't need more than 10 gallons of fuel on board. 

[maxfax]

The steel 55 will fit in the spare tire well of a bunny..   It's a tight fit, I had to bounce it in there with a mallet..  Nice part about that, no hold down needed...  IIRC I did massage things a bit at the very bottom of the well so that it would fit down down against the bottom, otherwise there was a half inch gap.. I could have made it shorter, but that ran into fitment problems for the goodies in the tank.. I welded a 2" wide ring (like a donut) to the top where I had cut it off, then made a round plate that bolted to that with a gasket so that I could open it up if need be.. The fuel gauge sender (universal type), pickup and return, and a nipple for the filler are mounted in the "lid" as was (for my case) a heat exchanger.. The pickup was just 3/8" brake line welded in there with no screen.. I opted for an inline fuel filter outside of the tank for easier cleaning..

I think when I was all said and done it turned out to be about an 8 gallon tank..  I'd imagine less the heat exchangers it would have been about 8.5 gallon..  A solid lit would work fine for plain ole diesel, since I used it for WVO I wanted the option to be able to get in there and really clean the thing out if need be..

Kevin, baffles are a MUST!!!   I did not put baffles in my tank, and I have darn near paid for it several times taking a turn a bit fast on wet roads.. So far the guard rail and poles have gotten out of my way...