Best ideas fuel cell fabrication. Lets get the diagrams/sketches Posted!

[Topdown]

if I am thinking right, the sump can be as "deep" as you want it to be... an inch probably wouldnt make a ton of difference but a foot would.

so the more baffles, the slower the fuel "moves" around in the tank, that makes sense.

The next issue is how to keep the sump full of fuel while off-camber when your running a shallow but wide tank. I am thinking that the best bet might be running two sumps and running the holley dual fuel pickup inside the tank so that one is always submerged... put one at each far side of the tank in the last chamber in a sump.

Then make each baffle open low right at the sump... or even a "flapper" type valve that would allow fuel into the chamber but would close off and not stop fuel from leaving the chamber but seriously slow it down... put one of those on each end chamber baffle.

Oh hell... I hate having idea's like this.

 

[ntsqd]

Perhaps I should point out that the pic I posted are the baffles "as veiwed from the top"?
When you tilt it you get a sump by default. Don't need any hangy down parts, works with a flat bottomed tank.

If you want more trapped fuel volume in place the 90* pieces use two pairs of baffles shaped like "[ ]" with one pair oriented East-West and the other pair oriented North-South.

 

[85m1009]

Here is a link to the cell I built for the Blazer http://www.mo-offroad.com/TANK2.jpg It was made of stainless and had two baffles front to rear. They ran the full length of the tank and had alternating half moon pieces cut out on top and bottom. The top ones are necessary for proper ventilation. To maintain fuel at all angles there is a 5 gallon square sump added to the bottom. The hole in the upper tank is just large enough to fit the sending unit into. No matter what angle you are at besides upside down there is at least two gallons of fuel to pull from. The sending unit is a stock GM saddle tank fuel injected unit with a weighted swivel pickup.

 

[BadDog]

"Weighted swivel pickup". Any more info? Just an extended rubber line for more mobility, or something more?

Also, the "no sump" method is very limited in low fuel situations. That baffle arrangement will trap fuel near the pickup, but it also traps fuel in other areas which is then unavailable at the pickup. Changing orientation doesn't help too much either since the entry to the pickup area is very small and most fuel changing sides is directed into the lost areas. And the pick up will still run dry on more extreme angles when below 1/4 tank or so (depending on proportions) due to drain out. Just imagine that baffle drawing as "top equals front". Now imagine low fuel and that the vehicle is 50* or so nose-up. See how the fuel would just run to the back of the tank past the arms of the "Y", leaving the center dry?

I do agree that that design is probably as good as it gets without a sump, but it can't compare to a sump constantly filled by directed flow (by baffles) and return dumped into the sump.

One other point to consider is that the return dumped into the sump is not ideal either due to fuel heat issues. Basically, the fuel is heated by the pump and engine proximity. Normally this is mixed with the cooler tank fuel and not directly returned. But if it dumps into the sump and pulls from the sump, then the hotter fuel is going to get returned to heat some more. This can lead to problems. When fuel is low, oh well, not much you can do about it, there is only so much fuel to carry/disperse the heat load. But when not so low, it would be ideal to work out a design to return fuel to the main tank rather than the sump, and then somehow redirect when it's low. I had in mind just pointing the return at the sump access hole from several inches above. If there is no fuel in the way, the jet should head right on in, but if fuel is above the hole, the jet will be at least partially disbursed into the surrounding fuel.

 

[bgreen]

Look up tygon tubing on google. its what snowmachines, model aircraft, and real aircraft use for their "clunks". (Clunk = weighted fuel pickup)

this is jmo, but fuel slosh isnt as much of a concern for most of the common offroad motorsports we are involved in. A tall, narrow tank, with a "Clunk" would provide the best of both worlds, IMO.

You can get very heavy wall tygon tubing which allows the tubing to be bent into very small radiuses to prevent the weight from kinking the tube shut.

 

[85m1009]

I obtained the pickup from a stock car racing friend, used. I imagine it is readily available from racing shops. I was a heavy wall tubing with a brass insert in the end for weight.

 

[juanblzer]

Russ is THE man!

Russ, your plans for a successful fuel cell definitely worked! I added some length and width to your plans to accomodate my fuel capacity desires and voila! The result was completely successful.
I currently hold 32 gallons when its topped off and havent suffered any fuel starvation since the new tank. The sump is basically a large box(think shoebox) fed by a small hole (big enough for the gm sender/pump assembly to drop into). I'm also running a baffle set up exactly like the drawings that Russ came up with. My only additions:
Metco Gm/sender ring
RCI (foamless) sender for fuel level (the stock one would not work in such tight confines)
a fuel filler neck
a drain plug...
Thanks for the schematics Russ! YOU ARE THE MAN.
oh and I tested it too!
No Spillage, not even a drop or a whiff of fuel and it was topped off bro!

 

[BadDog]

Sweet! Glad it worked for you. Always nice to be of some use.