Increasing fuel capacity

[Hollowpockets]

Hi all,

I've had an idea and want to put it out for opinion, Here's a basic drawing of my tank and pumps set up but I want to increase the capacity by even just a few litres to extend the range with minimal effort and expense, without removing and cutting open my tank AGAIN and fitting lift pumps, new wiring etc etc, I estimate doing a proper lift pump and swirl pot set up with labour to be in the region of £500+ and a heap of messing around but could do the below for about £100. Plus I only have a couple of weeks before season starts and I don't want to start ripping the car apart again.

Quite simply, would something like this work, if not, how could I make it work.



Cheers

[Hollowpockets]

Just to clarify, Jetstream have already fitted proper baffles and a fuel collector pot in the base

[mgbond]

How doesn't the extra tank get filled?

[mgbond]

How doesn't the extra tank get filled?

[Hollowpockets]

mgbond said:

How doesn't the extra tank get filled?

the level in the tank would raise up from the bottom as it would in the normal tank, theres no 1 way valve in it anywhere, then once the car is running and the level drops below the top of the little tank, pressure would dictate the split between the big tank and the small tank so there was always a small head of fuel in the little tank. or so I suspect

[YellowShed]

Graham,

How about not splitting the return to the big and little tanks. Go to the small one only, and have that vent to the original regulator return? That way, the small tank will always be feeding the pumps/venting into the main tank.

YellowShed

[andygtt]

Your planning to do what I have with the exception I kept the swirl pot in the tank itself so it could be 5L and a lot taller and thus give a better head of fuel to the twin 044's

Ive driven into a petrol station and put just over 61 litres into the tank and driven away so shows the difference in effective range to the stock tank.

My tank made from scratch was less than the pro alloy one AND it included the swirl pot and twin lift pumps!

[Hollowpockets]

YellowShed said:

Graham,

How about not splitting the return to the big and little tanks. Go to the small one only, and have that vent to the original regulator return? That way, the small tank will always be feeding the pumps/venting into the main tank.

YellowShed

Thanks Trevor, good suggestion and saves on cost of a y-piece and breather connection on the filler neck too.

See my question below though

cheers

Edited by Hollowpockets on Monday 17th March 16:46

[Hollowpockets]

Yeah Andy, I'll measure up the space in the side pod and then will start hunting for an appropriately shaped tank to fit, hopefully close to 5 litres.

One concern I have is the pumps pull the hot fuel from the small tank only until its dry, then suck in air with the fuel still coming from the main tank.

Is that likely to become a problem?

One thought I've had to reduce the effects of this is each pump has its own take off from the main tank, so should I tap the swirl tank into both pump feed lines, or just one so that at least one pump is always going to collect from the main tank and keep the fuel mix cooler or have the swirl tank tap into both pump feeds???....

hope that makes sense

Alternative could be to have one gravity fed 044 fill the swirl pot then one 044 after the swirl pot, would that work? would there be enough space?
Problem with that idea being back to relying on the single 044 after the swirl pot to deliver enough fuel.

Edited by Hollowpockets on Monday 17th March 16:58

[GTO600]

Graham question - are you allowed a fuel cell outside of what effectively is the crash structure ?

[Hollowpockets]

GTO600 said:

Graham question - are you allowed a fuel cell outside of what effectively is the crash structure ?

Good question, will go and dig out the blue book

[Hollowpockets]

Hollowpockets said:

GTO600 said:

Graham question - are you allowed a fuel cell outside of what effectively is the crash structure ?

Good question, will go and dig out the blue book

It is listed as a recommendation but not compulsory, so it can be done, obviously where possible I'll try to keep it all as safe as possible, thing is, even with our fuel pumps where they are, in a big impact to that area resulting in a ripped hose to the pump would allow the tank to empty anyway. You could perhaps weld on a box section structure around the inside of the pod but it would probably need the tub lifted off first.

[GTO600]

Wasn't sure but thought worth checking.

[andygtt]

Hollowpockets said:

Hollowpockets said:

GTO600 said:

Graham question - are you allowed a fuel cell outside of what effectively is the crash structure ?

Good question, will go and dig out the blue book

It is listed as a recommendation but not compulsory, so it can be done, obviously where possible I'll try to keep it all as safe as possible, thing is, even with our fuel pumps where they are, in a big impact to that area resulting in a ripped hose to the pump would allow the tank to empty anyway. You could perhaps weld on a box section structure around the inside of the pod but it would probably need the tub lifted off first.

I recommend you don't take the tub off as its just uncovered a whole heap of of things needing doing lol

Your pumps are outside the crash structure anyhow so don't see why a small fuel cell would be an issue.... with my tank I deliberately have close to double the needed capacity on my lifter pumps so that they turn over the fuel in the swirl pot and thus hot fuel doesn't stay in there long... as lifters don't deliver a pressure they draw less current and don't get as hot so don't charge the fuel.

[Gadgeroonie]

i saw a gumball car that had extra tanks behind the seats - the driver flicked a switch and a pump filled the main tank from them

would there be any advantage having a tank in the front for ballast ? you could pump it about to distribute weight

[Hollowpockets]

Mike,

No tanks allowed in the drivers cabin, unless I built a bulkhead between me and it on the other side of the centre tunnel but it's a lot of work which would only be worth doing if I needed a 100 or 120+ litre endurance tank. Even then I doubt myself or the car could drive for 2 hours between stops

[Hollowpockets]

Think I've figured out the final piece of this puzzle,

If I fit a one way check valve in both normal pump feed lines between the main tank and the point where the swirl tank taps in, that will allow the swirl tank to fill up when I fill the normal tank and also to stop G forces in left hand corners pulling all the fuel out the swirl tank to the main tank and letting air into the feed.