Fuel pick up - odd shaped tank

[100SRV]

Application:
100" Bowler with EFi Rover V8

I decided to simplify things and instead of having dual fuel lift pumps (reasons documented here https://www.pistonheads.com/gassing/topic.asp?h=0&... I'll instead opt for modifying the fuel tank and relocating the HP pump to the rear.

Main reasons are:
heat soak into the fuel causing occasional starting problems - the car does a lot of low-speed work and underbonnet temperatures can get quite high.
simple solutions are the best.

Problem is ensuring that the HP pump isn't starved of fuel (tank is a funny shape, vehicle gets used at odd angles).
The tank is long, wide and narrow (packaging reasons) which doesn't lend itself to persuading fuel to stay in the best place for a pick up.

Idea 1 is below - build a "collection box" inside the tank where the return feeds into it.
Image is from front RH corner and doesn't show how long the tank is.


The "collection box" has two holes - a small lower one to allow fuel in and a large upper one as overflow for the return.
Concerns are:
recycling hot fuel into the HP pump
will it stay full on funny angles and low tank levels? (I think so - the holes will be in the uphill face on the centre line)


Idea 2 is to use a Holley fuel mat which isn't cheap but is "off the shelf" and easier to install than getting this box made and then installing it.
Ideal 3 is a swing hose but I worry about the hose deteriorating with fuel contamination.

Idea 2 is favourite at the moment, have any of you used one?


100SRV

[GreenV8S]

Is the lower hole likely to be exposed to air for longer than a few seconds? I assume that would depend on fuel level and vehicle attitude. If it is, you might be better off with multiple sections with flap valves to encourage the fuel into the center section.

[stevieturbo]

No idea what you think that box is going to do ?

What is the current setup, that you mention dual lift pumps ?

Can the main tank not be designed so as not to need any additional parts ? Any pics or drawings of the main tank ?

And it sounds like you're saying you already have an external swirl tank of sorts ? Details...sizes ? Is that not sufficient ? As also asked, how long might the vehicle be at odd angles to cause problems ?

And the Hydramat is a pretty special piece, expensive for a decent size, but pretty amazing how it works.

[100SRV]

Thank you for replies

No idea what you think that box is going to do ?
Concept for discussion, idea is to trap fuel to keep the pickup submerged on steep climbs, off camber or slosh.

What is the current setup, that you mention dual lift pumps ?
LP lift pump adjacent tank (below bottom of tank) supplies swirl pot at front. Swirl pot above HP pump. Had random failures of LP pump, see thread link, hence desire to simplify.

Also sometimes get siphoning of fuel back to tank with engine off and high under bonnet temperatures.

Can the main tank not be designed so as not to need any additional parts ? Any pics or drawings of the main tank ?

Can post some pictures of tank. Want simple solution hence idea of collector dropped in from the top.

And it sounds like you're saying you already have an external swirl tank of sorts ?
See above
Details...sizes ?
One litre

Is that not sufficient ? As also asked, how long might the vehicle be at odd angles to cause problems ?
Minutes up to tens of minutes including periods with engine off.

And the Hydramat is a pretty special piece, expensive for a decent size, but pretty amazing how it works.
I've looked at the Holley website, might be best off-the-peg solution.

Need to do some maths based on fuel depths at climb and off-camber to see where the level is at various low volumes. This will inform where to place fuel mat or what to do with the box.

[stevieturbo]

Your thread link just brings me to the main pistonheads page, for some reason it does not go to whatever it should.

If the vehicle spends 10 minutes at extreme angles.....that's a lot of fuel movement and runtime to cover.
Realistically a rectangular box...with holes in it....is neither going to let sufficient fuel in, nor retain it in for seconds, nevermind 10 minutes ?

If you believe fuel temperatures are a concern, fit a fuel cooler.

To simplify, a low pressure lift pump in tank via hydramat to a swirl/surge tank with internal pump would be a neat solution.

The surge tank could also be incorporated internally to the main tank to keep everything neat and tidy

https://www.nukeperformance.com/product.html/fuel-...

3 litre as per that probably not needed though, but just for an idea.

Or Radium make nice stuff

http://www.radiumauto.com/FST-R-Fuel-Surge-Tank-wi...

I guess another option might be some sort of fuel cell with an internal bladder that might work for that sort of thing ?

[eliot]

Does the fuel return from the rail return to the tank or the swirl pot? if the latter, what about returning it to the tank? Would mean the LP has to keep up with the HP pump though.

[100SRV]

eliot said:

Does the fuel return from the rail return to the tank or the swirl pot? if the latter, what about returning it to the tank? Would mean the LP has to keep up with the HP pump though.

Fuel rail return goes to the swirl pot.

[100SRV]

Your thread link just brings me to the main pistonheads page, for some reason it does not go to whatever it should.

• Sorry. Original thread is "Fuel pump alternative" I believe you've very kindly contributed to that too.

If the vehicle spends 10 minutes at extreme angles.....that's a lot of fuel movement and runtime to cover.

• I thought about this and some of the green lanes I drive do have very long off-camber sections.

Realistically a rectangular box...with holes in it....is neither going to let sufficient fuel in, nor retain it in for seconds, nevermind 10 minutes ?

• Most of the time in off-camber operation the car is at idle so fuel consumption is low. Problem is to ensure that the box is large enough and doesn't drain too quickly.

If you believe fuel temperatures are a concern, fit a fuel cooler.

• Fuel temperature isn't a problem most of the time - it is heat-soak with engine off leading to restart problems which is. I get around that by running the LP pump for a short while until the swirl pot is full then gravity does the rest and I can start the engine.

To simplify, a low pressure lift pump in tank via hydramat to a swirl/surge tank with internal pump would be a neat solution.
The surge tank could also be incorporated internally to the main tank to keep everything neat and tidy
https://www.nukeperformance.com/product.html/fuel-...
3 litre as per that probably not needed though, but just for an idea.
Or Radium make nice stuff
http://www.radiumauto.com/FST-R-Fuel-Surge-Tank-wi...
I guess another option might be some sort of fuel cell with an internal bladder that might work for that sort of thing?

[anonymous-user]

You need to look at how aircraft pick fuel up from their tanks!

If you're seriously offroading, then the engine needs to stay fuelled at 100% gradient in all directions, ideally down to something like 20% of the tank volume as a minimum.

At this point, you're probably looking at a flexible pick up with a weight on the end....



If you have a metal tank, cover the weight in suitable bit of rubber fuel hose to stop in knocking !

[mywifeshusband]

Why not have two fuel tanks? A smaller (tall with small base area) tank of circa 1+ gallons capacity which has the high pressure feed to the engine. This can be fed by a bigger tank of any shape. When at extreme angle for sustained period the small tank will be able to supply the engine and it won't matter if it isn't being topped up by the larger tank.

[stevieturbo]

mywifeshusband said:

Why not have two fuel tanks? A smaller (tall with small base area) tank of circa 1+ gallons capacity which has the high pressure feed to the engine. This can be fed by a bigger tank of any shape. When at extreme angle for sustained period the small tank will be able to supply the engine and it won't matter if it isn't being topped up by the larger tank.

It seems he already has a surge tank setup like that, he just wants additional backup to maintain that supply to the surge tank.

[AER]

Max_Torque said:

If you have a metal tank, cover the weight in suitable bit of rubber fuel hose to stop it knocking !

That's an innovative method of knock control...