I've been throwing around an idea for a while, what would be involved in making your own fuel tank/cell? Could I just weld a leakproof aluminum box with a filler spout, and the appropriate fittings for a fuel pump, etc.?

Mathius

yeah and you'd need to figure out how to get the "foam" or whatever they call it inside the tank, or make baffels, but i don'tthink it'd be as good as the foam.

What purpose does the foam serve, and how is it applied?

Mathius

It isn't applied, it is basically just a big block of foam that is put inside the tank. Its purpose is to prevent or at least lessen fuel slosh.

i cut my tank open to weld a sump on and never saw any foam in there

They don't put them in factory tanks, it is more for racing. Because when you launch or take hard corners, your gas sloshes around in the tank. They put the foam in there to prevent this from happening. Look in any aftermarket fuel cell, you'll see it.

hey i believe you lol so why no foam in factory tanks? i would think a street car would have more sloshing gas then a track car

You know, that is a good question. I'm going to have to say that I don't know the answer to that one.

ive heard of products that give your tank that inner foam lining. wont attempt using one though

Our factory tanks had no inside baffles at all? I'm gettin ready to sump out a different tank for my car so I'm anxious to get inside and take a look see after hearing this. I made a fuel cell for a buddies 29 Ford and we installed 2 baffles inside. Left an 1" clearance off the bottom of the tank and drilled 2 more 2" holes per baffle as well. Do take this advice if you plan on making your own pressure test it. I left and he was going to test it before installing and fitting, well he filled it alright- with gas, and found a pin hole, said he had faith in my welds-duh. Next afternoon I get a phone call from him asking if I could come fix it up for him, once I got there his arm was all bandged up. Found out he just dumped the gas out, ran some water through the tank and when he tried to weld that spot he had his forearm right in front of the filler tube-the arc sparked up the vapors and shot a nice flame onto his arm and gave him 2nd degree burns, so be careful if you dont know what your doing.

becarful when you cut the holes for the sump. i chopped the thin brace that was inside the tank. gave it a nice little slice. when i drained my tank, i funneled the gas out with a siphon and filled it with water and let it sit for a few days then rinsed it out. had no problem welding it

Did you just cut too deep when that happened? and what was the general vacinity of that brace your talking about? center of the tank towards the bottom?
I'm lucky I got a buddy that parts out 3rd gens and I have a Texas rust free tank to play with Think I'm gonna install a AN fitting also so I can just run the return line straight up from the pump. I'm knocking on wood as I type this, but played with fire and fuel tanks in the past and still have all my hairs instact I think my budy had one serious brain fart going that day and got lucky with only 2nd degree burns. Been in the shop before when this has happened and have heard the the high pitched "thaarup" sound coming from the vapors igniting and blowing out the fill tube. For some reason it got my heart beating a little faster

money my friends. if you have to put in foam say its only 10 bucks a car. multiply that by say 5million cars and walla thats alot of money the generals out thats why if your rebuilding a engine and you have left over bolts ur an you never have extra bolts when it comes to building cars from the factory:werd:

Well just my .02 worth, but the reason they put the foam in fuel cells is to take up space that would otherwise be occupied by vapor. It help keeps the tank from exploding during an impact and yes it also serves to keep the fuel from sloshing around. I dont recommend putting foam in a fuel cell your building as it tends to break down over time and clog your fuel system. Most of the experienced racers and performance shops in my area all remove the foam for this reason and have had no problems. I do however recommend running an aluminum over a plastic tank as the plastic tank tends to collapse alittle over time after the foams removed. Though it really doesnt effect the fuel delivery it can make the tank come loose from its mounts when it collapses too much.