I'm currently designing my new tank before sending the designs off to the laser-cutters and there's a couple of things I'd like to bake into the design regarding fuel delivery.

If I put a swirl-pot arrangement into the tank (as per the sierra tank snail-shell system) and a lower gated sump as part of the tank, then I should be guaranteed a constant pressure to the HP pump.

So, I'm wondering if I can't run the HP pump straight from the tank, straight to the injectors, pressure regulator, and return back to the tank into the swirl pot.

I've seen that SBDev advise low-pressure to high-pressure pumps in one of their designs, and the traditional swirl-pot, two pump design as well.

Ideally I'd like to avoid an external swirl pot if possible, and even use an in-tank HP pump if there's one available with a suitable installation kit as well.

Has anyone had any success with this kind of arrangement, or has a reason why it would fail or be unreliable?

High presure pump direct from tank to fuel rail is fine and how 99% of cars on the market run. Most are now in tank pumps but there's been plenty of externalones over the years.

My tank has a sump thats 150mm dia and 70mm deep on the bottom of the tank with only a 70mm diameter hole between that and the tank. That forms a lip and keeps the sump full enough on cornering. The feed come off the bottom and the return is back into the sump. Never had any problem.

That should work fine as long as your feed to the pump is big enough, Ford have used the same system for years to feed a Bosch pump - pipe MUST be 1/2" bore to supply the pump and prevent cavitation.

In tank pumps are the way to go if possible, a lot depends on the shape the tank.


A lot of production cars now have saddle shaped fuel tanks, the pump sits in one side of the tank in swirl potis continuously overflowing., and the return flow from the pressure regulator goes into the top of the pot. There is however an additional trick applied the return flow from the regulator goes through a venturi the suction of which is used to scavenge fuel from the opposite side of the tank.
As a result the swirl pot i

Lots of intank pumps out there, most seem to be spring-loaded so can be used on a range of tank sizes. Golf 4 are a reasonable size, as are freelander (think they have a built in pressure regulator too) as well as mgf, landrover and many many others.
Ebay provides helpful pictures!

I get that - similar to the way a spray gun sucks up paint, or in my case, a wine aerator pulls air in? I take it you mean only one in-tank HP pump?

I've been looking at fuel coolers as well, as there are lots of discussions out there about fuel temp, especially if the the bosch 044 pumps are running at full chat when they can draw 10A and that's a lot of heat to dissipate.

I won't have a saddle shape tank, and to describe it crudely, it'll be a T shape, with the lower part of the T going down into the transmission tunnel, and the upper part sitting in the void above the rear wheels. This means the mass of the fuel is moved inboard and low down, rather than behind the rear wheels, reducing polar moment of inertia, and moving the centre of mass forward. It lools like I will have an option to put a flatish swirl pot in the upper part of the T and the fuel pump in the lower part (acting as a sump). In this case I think I get what I need - energy taken out of the fuel, and a constant feed to the pump under cornering loads. I'll baffle and gate it regardless, especially between upper and lower parts of the T, so once fuel is down there, it stays down there.

In my fury, it would be easy enough to take the output from the fuel rail down to the chassis rail between the shocks, from there into the regulator, from the regulator to the fuel cooler mounted along side the radiator and oil cooler, and from there back to the tank.

This arrangement gives me the option later to add a long-range tank in the place where the old tank went, which could be attached via a dry coupling, or on a solenoid valve, and just run dry for the track.

venturi fuel sucker used by BMW MINI and Rover 75


Return from the regulator goes in through the semi-transparent brown pipe does a u-turn and out through the larger bore grey pipe. The scavenged fuel is sucked in through the blue grill visible in one photo sucker2




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isn't physics great?

Just another one - I see lots of pumps advertised out there, but struggle to see flanges for in-tank pumps. I see the kits but noone seems to include either a bolt-in or weld-in flange with their pump.

Any suggestions?

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Originally posted by FuryRebuild

This arrangement gives me the option later to add a long-range tank in the place where the old tank went, which could be attached via a dry coupling, or on a solenoid valve, and just run dry for the track.

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Thanks Davie

I think removable with a dry coupling is the way ahead. It's far more on the list of nice-to-haves than part of the rebuild.

I am probably going to start trailering it to track days though - having lost it before on a practice session taught me that it is best to not expect to get it home