Custom Petrol Tank for Fuel injection

[Dorian]

For fuel injection I'm aware that the Stag tank has fuel supply and return connections on the top but also aware that injection pumps generally need a low restriction larger diameter feed and don't suck very well.
Has anyone fitted a high flow immersed pump into a Stag?
I've ended up with an over complex system which takes a 10mm connection from the bottom of the tank through a low pressure pump which feeds a remote header swirl tank which in turn feeds a high flow pump via large bore pipe. I don't like the idea of the gravity feed in the event of a rear end shunt and I get a petrol smell in the boot which I think are the pipes sweating slightly.

The ideal would be an aluminium tank I guess with a pump built in but it needs enough flow for 500hp.
What has everyone else done with EFI (I appreciate I need more flow than most)?
Thanks Dorian

[KOY 23]

I have a similar system to yours but use standard Stag plumbing to SU output, which feeds swirl tank, swirl tank return into currently blanked off tank return via 0.6mm mig tip restrictor. Swirl tank output into high pressure pump and fuel rail return into swirl tank. Works fine as I didn’t want to modify tank. I think Steve (Stagdad) dropped a Range Rover pump into his tank.
A drop in pump from a big Merc should give you the flow you need,

[Phil S]

We had similar problems with some if the kit cars we built thar were in the same bhp range.
ford and volvo external pumps easily produce sufficient flow and pressure for 500 bhp.
they used a small swirl pot of about 1L capacity fitted Close to the engine

[Dorian]

Interesting, I use a Bosch 044 pump which draws nearly 10A and lifter pump, combined nearly 14Amps which I'm sure could be reduced too. The tank was modified to have an extension piece on the bottom with the outlet from there which worked but later I had concerns about getting a constant feed when the tank was low, hence the swirl tank was added in the void next to the fuel cap. My main issue is the constant fuel smell. The tank isn't rusty and has been out at least 4 times, been pressure tested, then another time a dye added and finally recently I epoxy lined it just in case there was a pinhole I had missed. All the plumbing replaced 4 times now the latest with R9 hosing, new pumps and filters and it still smells!
The simplest things always seem to give the biggest problems..
So since I have so many supply and return hoses I can only assume the pipes sweat a little and that enough to smell?
A tank with integrated pump would cut that down and also make it safer.
Does anyone know who makes the Ali tank I see advertised, I may talk to them about a version with a suitable pump?

Thanks again..

[KOY 23]

I had trouble sealing the banjo bolts to the SU pump, I found after a lot of pressure checking tanks and joints, that the recess in the pump was deeper than the fibre washers, so the washers weren't sealing, double washers and liquid PTFE cured it.
Agreed about the tank with integrated pump, as it would drastically reduce the number of potential leakage points.

[new to this]

Ive done the same thing as Stag Dad,put the pump inside my Dolly Sprint tank,im also using an6 fittings with stainless hose


Dave

[bullstarz]

I went for two red top lift pumps filling up two injector swirl pots, each of which have a Bosch 044 FIP in. There’s also 4 filter and accumulator.

[jakesmig]

My present system mirrors yours and works well but is cumbersome and with 2 external electric fuel pumps,1 lift & 1 high pressure, it is quite noisy. The tank is also of dubious integrity resulting in occasional petrol fumes which is disturbing.
I also run 4 dipped & 4 main headlights, an electric cooling fan, electric power steering and full EFI ignition and fueling and there are times when there aren't many spare amps left.

I've opted to make a new fuel tank with a Range Rover in tank pump which will drop 1 fuel pump out of the system and will massively clean up the plumbing at the same time.

When looking for a fuel pump the volume delivery is obviously important but the primary requirement is to match the pressure delivery to the injector requirements & ECU programability. The injectors will have a serial number and a Google check will indicate the volume it passes at set fuel pressures. These volumes and pressure generally need to be installed in the ECU settings for proper running. The quality of pressure valve is also relevant.

The rally Escort I'm involved with churns out about 250BHP on Webbers and does about 4MPG at full chat through forest stages and the fuel pump doesn't deliver huge volume, but it does deliver at constant pressure.

John.

[Dorian]

I didn't realise you could immerse a pump in a standard tank! How do you deal with the electrical connections passing through and into the tank and the mounting of the pump? Would this retain the standard float level sensor too?
It always amazes me that there so many regulations for electrical products in potentially explosive environments in industry, but in the automotive world you run petrol through a pump possibly in a tank of petrol with just a 15amp fuse for protection! It seems to work though....
I have 440cc Bosch injectors from memory and run about 40psi, I can't remember the duty cycle but could check the MAP.
As you say Jake, the Amps all add up! I've just converted to LED lighting to help that and it seems to cope quite well, but having a 20A + 2 x 15A fans, 14A fuel pumps, plus the ECU things could get tight at idle, so anything to reduce that overhead is good.

[KOY 23]

92C9F38C-1309-46AF-AC81-3F4C929C5F3E.jpeg Typical in tank fuel pump.

[bullstarz]

The swirl pots are possibly the easiest solution, as they always have a constant supply of fuel. But you do loose some boot space.

8444DA65-2288-4F97-9AFC-B78F6E4FCB5B.jpeg

[barkerwilliams]

Stunned, that is some plumbing.
Alan

[mjheathcote]

The swirl pots are possibly the easiest solution, as they always have a constant supply of fuel. But you do loose some boot space.

8444DA65-2288-4F97-9AFC-B78F6E4FCB5B.jpeg

Show off

[Dorian]

Wow, serious stuff, much better done than mine is now but it's even more complicated!
The photo is an example I guess of a Land Rover standard unit and suspect would need a swirl pot added in the bottom of the tank the sit around it?

Ideally what I would like to do is to buy a new tank such as the Aluminium one already available, but have it built to take an appropriate immersed pump.
Alternatively use a new standard tank with a lifter to the swirl but maybe find space under the car for all this plus the pump to minimise the smell problem!

More thinking required..

[Dorian]

I've been looking into this further and it looks like the Alloy tank already made for the Stag has been made with the provision for an internal pump (see picture below)

Standard
Ali stg tank.png
With extra Pump fitting flange
Ali stg tank with internal pump.jpg

The fabricator wants me to supply the pump assembly including integrated swirl pot and he will adjust the fitting accordingly, but finding one that flows enough for 500+hp that is quite shallow (I dont know the actual depth available) is difficult.
The one Koy suggested is along the right lines but probably not up to the flow...

I found a Universal fitting for a Evo (see link) https://www.ebay.co.uk/itm/174654227...4AAOSwjDZYiW2U
but it doesn't have a swirl pot.

Any ideas anyone that isn't too exotic?

Thanks Dorian