FuryRebuild
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| posted on 21/8/12 at 08:48 AM |
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In tank swirl pot straight to high pressure pump - design advice wanted
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?
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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adithorp
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| posted on 21/8/12 at 08:58 AM |
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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.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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BaileyPerformance
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| posted on 21/8/12 at 09:09 AM |
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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.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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britishtrident
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| posted on 21/8/12 at 10:27 AM |
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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
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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cliftyhanger
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| posted on 21/8/12 at 10:57 AM |
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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!
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FuryRebuild
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| posted on 21/8/12 at 10:57 AM |
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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.
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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britishtrident
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| posted on 21/8/12 at 11:14 AM |
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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
 
Description
 
Description
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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FuryRebuild
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| posted on 21/8/12 at 11:18 AM |
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isn't physics great?
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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FuryRebuild
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| posted on 22/8/12 at 07:01 PM |
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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?
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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daviep
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| posted on 22/8/12 at 07:29 PM |
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quote:
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.
The idea of a long range removable tank is good the idea of having it fitted to the car empty is terrible. Tank full of vapor is just about the
closest thing you can get to a bomb.
Cheers
Davie
“A truly great library contains something in it to offend everyone.”
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FuryRebuild
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| posted on 22/8/12 at 09:42 PM |
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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 
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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