Outer Limits 4x4 Board

I have tried to build the ultimare efi off road fuel tank

This is what i wanted out of my fuel tank

only one elec high pressure pump (no elec lift pump)
surge tank
the truck can be run for extended period at any angle(for winching etc)
light weight
rock, drive shaft and stone resistant
able to support the weight of the truck
low profile with flat botton (no pump well)

This is what i did

the heart of the tank is the intergral surge tank this is where the HP pump lives




there are then 2 motive flow venturi pumps mounted 1 at the front one at the back that fill the collector(surge) tank






until it over flows back under fuel level to stop unessary evaporation





the tank is constructed on the bottom and tailshaft side of 6mm aluminium
this is where it is mounted from for max strength


sender unit is mounted in the main tank chamber with an extra pump in case of main pump failure (dont want to be stuck as the tide comes in)



any how what do ya think ?
any ideas for futher improvement would be great

cheers

thrashlux

Turns out i cant read and my eyes are painted on

Comment withdrawn haha.

Possibly cage in the 2 pick up pumps that are filling the surge tank with 1/2inch holes etc in the bottom so when the truck is on unlevel ground etc the fuel doesnt run away from the pickups and they're not running dry, the holes giving you some time before the fuel drains from the pickups etc and obviously so the fuel can flow in and around, maybe some baffling to stop the sloshing around.?

I'm no good at explaining things but i'm sure you get what i'm saying.

Thanks for your ideas

there is a baffle its just hard to see

the motive flow venturi pumps can run dry all day long they have no moving parts they are powered by the return fuel from the return line a if the fuel is not at one pump it is at the other
the reason i did not have little walls around them was so that if a wave of fuel went past at low level it would get gulped up on the way past

there is also a 1 way valve on the collector tank to allow fuel to enter the tank via gravity from the main tank in addition to the venturi pump

I was probably not very clear or explained how it all worked

cheers jonathan

I'm not an expert with fuel tanks, but with fuel constantly being pumped in and a one way valve for gravity filling, will it create a vacuum? in the surge as the fuel is drawn to the engine bay?. is there an overflow back into the main tank from the surge tank area as there is in normal external surge tanks?

berad wrote:I'm not an expert with fuel tanks, but with fuel constantly being pumped in and a one way valve for gravity filling, will it create a vacuum? in the surge as the fuel is drawn to the engine bay?.is there an overflow back into the main tank from the surge tank area as there is in normal external surge tanks?

The venturi pumps can pump about 5 times the volume of the main pump
causing the surge tank to be continuosly overflowing with fuel if there were not a over flow the surge tank would presurise

there will be an intial drop in fuel level in the collector tank due to it having to slowly gravity fill but no vacume as air will enter through the breather from the main tank,
this drop will only occur as the system primes for the first time filling the fuel lines but as soon as return fuel is available there will be an over abundance of fuel in the collector tank from he venturi pumps
(the gravity fill is only used for intial fill and priming of the collector tank)



the over flow is that funny looking pipe on a 45 deg angle returning it to under the surface fuel to stop tumbling , airation and reduce losses due to evaporation

jonathan