having a in bed aux fuel tank made

[emarsh]

A buddy owes me a big favor and said he would gladly make the tank for me. He is an excellent aluminum welder as a profession and said to draw him some plans and he will make it. I have a roll & lock bed cover and the tank will be just under and to the rear of the roll up part. It will be gravity feed to a aux pump so that I can fill up my VW Jetta Diesel as well as transfer to my 02 Ram factory tank. I plan on a 1/2 inch outlet at the bottom and a 2 inch fill along with a vent, plus baffles inside. What other considerations should I concern myself with?

 

[B.G. Smith]

Put a filler nozzle on both sides of the tank, makes it more convenient and at some RV filling islands there are nozzles on both sides from the same pump. bg

 

[chuckwilson]

Put a vent line from top of aux tank to the filler neck in your stock tank so it will gravity feed!!!!!!

 

[rweis]

A gauge to know how much is in the aux tank. I use a mechanical gauge, no need for electric.



A shutoff valve for the aux tank to be able to work on the OEM system and not have to empty the aux tank to do so. Also you can pump the OEM tank into the aux tank with the shutoff valve closed to be able to work on the OEM tank, then refill the OEM tank from the aux tank.



Do not vent off the roll over valve, somewhat unpredictable in flow rate of fill. Use the optional fuel return on the tank cannister as a OEM tank vent or the vent on the DrawStraw (orgional) to the aux tank.



Vent your aux tank to the atmosphere through a lawn mower fuel filter so bugs do not clog up the vent line.



DO NOT return the VP44 return line to the aux tank unless you have a REALLY LARGE line from the aux tank to the OEM tank. The VP44 can return 31. 5 gph at cruise speed and can overtake a gravity feed line to the OEM tank and start filling your aux tank faster than the aux tank will gravity feed the OEM tank.



DO NOT use the Northern Tool fuel filler line adapter for the aux tank to fill the OEM tank. There is a very small restriction in that mechanism that will not even keep up with normal unloaded fuel usage out of the OEM tank.



BOLT it down well so it does not shift.



Just some thoughts,



Bob Weis

 

[steved]

Put a vent line from top of aux tank to the filler neck in your stock tank so it will gravity feed!!!!!!

They will gravity feed without being vented to the main tank... mine does, and I know I'm not alone. With 3/8" lines, mine will easily keep pace with demands.

 

[JLandry]

A gauge to know how much is in the aux tank. I use a mechanical gauge, no need for electric.

Ditto. Here's a good place to buy mechanical gauges:



Krueger Sentry Therma Gauges - Stainless Steel



That's the model I use on my aux tank.

DO NOT use the Northern Tool fuel filler line adapter for the aux tank to fill the OEM tank. There is a very small restriction in that mechanism that will not even keep up with normal unloaded fuel usage out of the OEM tank.

I disagree completely with this one.



I have an RDS aluminum aux tank and the gravity flow filler neck kit from Northern Tool on my truck, and the flow rate exceeds the truck's consumption rate by quite a bit. My experience has been that *if* the aux tank isn't adequately vented, then yes, in that case the gravity feed flow rate of the filler neck kit will be very slow (if at all), and it might not keep up with the truck's consumption.



In my truck the gravity feed flow rate seems to be about 8. 5 gallons per hour. So in theory that gravity flow rate should be adequate down to less than 7 mpg before it can't keep up with the truck's consumption rate. I've personally never seen fuel non-economy that bad, even when towing my travel trailer in mountainous terrain.



John L.

 

[PRout]

I had mine set up for gravity feed but used an inline filter. It worked "ok" (so-so) for about a year until the filter started getting clogged and gradually slowed the flow to the point that it wouldn't keep up while towing the trailer.

Ended up plumbing the OEM lift pump inline and control it with a mini toggle switch/relay combo. Also used a manual tank valve down by the driver seat. Sure sped up the transfer process. Just make sure you have a timer, red led, or some kind of reminder that you are transferring fuel or you WILL overfill the main tank. (not that I've ever done that or anything ). Just something else to consider.

 

[rweis]

The VP44 uses 70% of the fuel for cooling. The max flow rate is 45 GPH. 30% could be used for injectors. 30% of 45 GPH = 13. 5 GPH used.



JLandry "In my truck the gravity feed flow rate seems to be about 8. 5 gallons per hour".



Might be my setup. Each setup is a little diferent.



Bob Weis

 

[JR2]

I would put some kind of valve (electrical or whatever) so that if you ever get in an accident and the tank get moved around it does not "gravity feed" fuel all over the place. I believe there is a DOT law about in bed tanks and gravity feeding your stock tank.

With that said most of the tanks I have seen where set up just the way you describe. If it where me I would use a lift pump to pump fuel into your stock tank... you could put a check valve in so that if the lift pump is off it will not gravity feed to the stocker. I bet if you where really clever you could tie into the fuel level gauge wires to turn on/off your fill pump.

 

[PRout]

I bet if you where really clever you could tie into the fuel level gauge wires to turn on/off your fill pump.

That would be slick! Could be used as a fail-safe device if you forget.