Hey guys first post! - Pirate4x4.Com : 4x4 and Off-Road Forum

rotarygod · 01-27-2009, 12:49 AM

I guess this would go here but if not mods feel free to move it.
I would like to add another fuel tank to my rig for extended range driving. I have all the space I need under the rig for a 30 to 40 gal tank depending on the shape of the tank. None of that is an issue my question lies in the fuel lines and pumps. It is efi with an in tank pump now and the reserve tank will also be this configuration. The question is when I have one pump going and the other off will the fuel back flow through the pump that is off or will the pump prevent that, or will I have to plumb in a pair of one way check valves at each tank to keep the backflow from happening?

Thanks in advance guys!

big giant head · 01-27-2009, 04:06 AM

Are you going to let us in on the secret of what the fuck this vehicle is?

roscoFJ73 · 01-27-2009, 04:18 AM

Quote:

Originally Posted by rotarygod

The question is when I have one pump going and the other off will the fuel back flow through the pump that is off or will the pump prevent that, or will I have to plumb in a pair of one way check valves at each tank to keep the backflow from happening?

Thanks in advance guys!

I think the pumps in their off position would stop fuel flowing backwards.

Sometimes the best way is to add an auxillary tank and use that to feed the main tank when its empty.

My Landcruiser has dual factory fitted fuel tanks and the plumping is diabolical

rotarygod · 01-27-2009, 05:35 AM

Quote:

Originally Posted by big giant head

Are you going to let us in on the secret of what the fuck this vehicle is?

I'm not sure I have a flame suit that's good enough for the hell I'll catch.

roscoe: not a bad idea, the only thing that worries me with the piggyback feed system is I'm supercharged so I need a good flow rate, probably much more than even the stock pump to feed the main tank. I suppose a 255 walbro would do the job.

BAGDADEXPRESS · 01-27-2009, 09:38 AM

I strongly suggest you find your fuel rate and not over fuel your motor. Then go to WALBRO for best deal on the properly sized pump.

Over fueling & over pressure can become the grim reaper coming to claim your motor.

Many motor vehicles have 1 main tank then another aux tank mounted higher than the main one, Volvo comes to mind here where aux is mounted higher that main tank. An on/off fuel flow valve in aux fuel line is good for gravity feed to top off main tank. Usually, in a 1 tank higher than other situation the upper tank is filled to fill both tanks and having plumbing to suit install.

There are switcher valves that can incorporated into your system but tanks must comply w/current epa guidelines in your a/o, meaning that if it's un-vented the aux tank needs to be un-vented too.

Safety first, tanks cannot be mounted in an interior area (say trunk) w/o air tight bulkhead between trunk and pass compartment.

rotarygod · 01-28-2009, 04:23 AM

I believe it has a regulated return line like most of my cars so the excess fuel is simply rerouted back to the tank. I'll have to check.

I think my mounting location will be higher than the factory one but only 4-5 inches.

As for location that goes without saying. The only way I'd put a tank inside a vehicle body would be a safety cell in a race vehicle, besides why waste all my glorious interior space for a fuel tank. It would have to go in the back where I carry all my recovery gear. My mount location is underneath in the back like a cherokee or most small suv's.

Thanks everyone for your input.

01-27-2009, 12:49 AM	#1 (permalink)
rotarygod Registered User Join Date: Jan 2009 Member # 128265 Posts: 3	Hey guys first post! I guess this would go here but if not mods feel free to move it. I would like to add another fuel tank to my rig for extended range driving. I have all the space I need under the rig for a 30 to 40 gal tank depending on the shape of the tank. None of that is an issue my question lies in the fuel lines and pumps. It is efi with an in tank pump now and the reserve tank will also be this configuration. The question is when I have one pump going and the other off will the fuel back flow through the pump that is off or will the pump prevent that, or will I have to plumb in a pair of one way check valves at each tank to keep the backflow from happening? Thanks in advance guys!

01-27-2009, 04:06 AM	#2 (permalink)
big giant head Registered User Join Date: Dec 2007 Member # 105299 Location: Nova Scotia,Canada Posts: 321	Are you going to let us in on the secret of what the fuck this vehicle is? __________________ Owning a handgun doesn't make you armed any more than owning a guitar makes you a musician.

01-27-2009, 09:38 AM	#5 (permalink)
BAGDADEXPRESS Registered User Join Date: Sep 2008 Member # 120891 Posts: 113	Fuel rate I strongly suggest you find your fuel rate and not over fuel your motor. Then go to WALBRO for best deal on the properly sized pump. Over fueling & over pressure can become the grim reaper coming to claim your motor. Many motor vehicles have 1 main tank then another aux tank mounted higher than the main one, Volvo comes to mind here where aux is mounted higher that main tank. An on/off fuel flow valve in aux fuel line is good for gravity feed to top off main tank. Usually, in a 1 tank higher than other situation the upper tank is filled to fill both tanks and having plumbing to suit install. There are switcher valves that can incorporated into your system but tanks must comply w/current epa guidelines in your a/o, meaning that if it's un-vented the aux tank needs to be un-vented too. Safety first, tanks cannot be mounted in an interior area (say trunk) w/o air tight bulkhead between trunk and pass compartment.

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01-28-2009, 04:23 AM	#6 (permalink)
rotarygod Registered User Join Date: Jan 2009 Member # 128265 Posts: 3	I believe it has a regulated return line like most of my cars so the excess fuel is simply rerouted back to the tank. I'll have to check. I think my mounting location will be higher than the factory one but only 4-5 inches. As for location that goes without saying. The only way I'd put a tank inside a vehicle body would be a safety cell in a race vehicle, besides why waste all my glorious interior space for a fuel tank. It would have to go in the back where I carry all my recovery gear. My mount location is underneath in the back like a cherokee or most small suv's. Thanks everyone for your input.