Fuel Tank for Injection Engines

[flyerncle]

I built a roadster for someone to race and it used Ginetta G20 engine and box diff etc,all Quaife and brand new.
The fuel tank was from Rally design and foam filled(designed for nitro but no probs with petrol)it suffered fuel surge at half a tank for no earthly reason.

Low pressure pump through large FI filter to swirl pot and HP pump to FI filter to rail and now no problems,over capacity is better than being close to capacity.

[baz-r]

sumped tank

[flyerncle]

Perzactically (mix up of perfect and exactly)

[Josh]

Update on my fuel tank progress (and questions!)

I have folded the main section of my tank from 2mm half-hard ali (left over sheet from my floor). It is exactly to the book specification; however it's a very (very!!!) tight squeeze to get it into position on the car. And I think the tank is deforming slightly as I push it in - it won't be able to do this once the tab has been welded in place and the sides/baffle welded in. Is there a trick to getting the tank in other than force in from the top?



I've brought myself a Mondeo in-tank fuel pump and level sensor which I plan to fit into the top face of my tank. It's just the right height to have the L-shaped fuel filter/pick-up sit just off the floor of the tank.

I'm thinking of constructing an internal swirlpot to prevent fuel starvation. This would probably be four 'walls' that sit around the 'L' with many small holes to prevent fuel rushing out. Will this work? I'm thinking the walls will have to be high enough to stop fuel rushing out over the top.

Thanks
Josh

[alga]

Yes, the book tank is very, very tight. Mine is a bit bigger than the spec due to bend radiuses. When pushing in place, it contacts the rollbar rear stay bracket gusset plates and the rear vertical tubes. Massaging the relevant places with a heavy hammer helped. That said, I had removed and reinstalled the tank without too much bother last week.

Also, pay attention to the material thicknesses when making sides of the tank. I had to ditch the first attempt as they were too tight to fit on the main section with this thickness. Now the extra sides serve as trays for the nuts and bolts.

I cannot comment on the internal swirlpot, I have no experience whatsoever with them, but I have doubts about them theoretically. Cars like this corner on the skidpad at around 1 g, meaning the surface of the fuel will lean at 45°. If you have a third or a tank of fuel, how long will you be cornering until all fuel escapes from the swirlpot? Also, remember that a typical injection fuel pump circulates at least 2 litres per minute, high performace pumps up to 5 litres per minute.

[flyerncle]

Put sump on tank and junk in tank pump,it will cause problems with fuel surge as Albert suggests.

[Josh]

I had a look inside a Ford Granada fuel tank my dad had lying around today. This had an internal 'swirlpot' arrangement which sat in a very slight recess/sump (about 15-20mm deeper than the bottom of the tank). The internal pump and fuel level sender unit was very similar to the Mondeo one I have.



I am now planning on folding up a similar 'maze / spiral' that will allow for my 'L' fuel filter/pick-up to sit inside. I will cut a hole in the base of my tank and slide this in such that around 20mm sticks out below and a further ~50mm sticks up above. This will then be sealed on the outside with a small side blanking plate and a sump floor plate.

I will then make an insert with a sunken lip to allow my Mondeo pump/level sender unit to sit down lower than the top of the tank, such that the 'L' fuel pick-up sits on the floor of the sump.

I'm confident this will work; it seems to work for Ford! Your thoughts though, please?

Josh

[voucht]

When I read your previous post, that is exactly what I thought about. Same system in the fuel tanks of EFI Sierra, and I guess it really avoids fuel surge. If you build a similar "maze" in your fuel tank, I think you are safe. Just my modest opinion though...

Another thing, if the "L" shaped filter of the Mondeo takes too much room, you can have smaller ones ("I" shaped ), like the one from the EFI pump of the Sierra (you can see it on the last pictures at the very end of this post of my blog: http://vouchtroadster.blogspot.se/20...reservoir.html)

I bought a brand new one from FSE Glencoe. I've been working with this company for 15 years, and they are in the UK, you can order one from them, you have the choice. Just check the diameter of the fitting, but I'm sure you'll find something to replace yours if you need to.
http://www.glencoeltd.co.uk/walbro-f...in-tank-parts/

Good luck

[alga]

Very smart!

One more consideration. The swirlpot below the bottom of the tank allows one to run the tank to nearly empty, not to mention the 1 l of extra capacity it adds. This design will require a couple of litres left in the tank for the pump not to suck air.

On my 2l Zetec with factory ECU the fuel usage is ~8.5 l/100 km, meaning the range is below 300 km.

I took a pic of my swirlpot when the tank was out:
http://imgur.com/4eZ7pIh

Here you can see it stick out at the back, as you see it's not in harm's way:

[baz-r]

Originally Posted by alga

Very smart!

One more consideration. The swirlpot below the bottom of the tank allows one to run the tank to nearly empty, not to mention the 1 l of extra capacity it adds. This design will require a couple of litres left in the tank for the pump not to suck air.

On my 2l Zetec with factory ECU the fuel usage is ~8.5 l/100 km, meaning the range is below 300 km.

I took a pic of my swirlpot when the tank was out:
http://imgur.com/4eZ7pIh

Here you can see it stick out at the back, as you see it's not in harm's way:

very like mine and mine works a treat
external pumps make life alot easier
put a baffle at the center like wit a hole under it so left/right slosh keeps it full in the corners