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V8 fuel pump options with custom tank


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Right, I have seen this covered in some other places and taken on board the advice, but it hasn't *quite* answered my precise query....

I have a custom tank, originally used for the devils fuel, and as such it has breather, flow and return, all 8.3mm OD, and then of course the 50mm filler. As you can see in my sig, I run an EFI V8, meaning a bit of swaparoonees needs to be done, I think. EFI pumps don't suck well, but some external pumps are OK as long as they are below the bottom of the tank, which mine would be.

So, first option, an external fuel pump, these are available off the shelf, Sytec being one manufacturer (as well as numeroous OEM Bosch units), a bit spendy at around £80.... One problem with this is the fact that almost all EFI pumps have a 12mm inlet, and 8mm outlet, will this mean the 8mm pickup on the fuel tank is not big enough? I can physically join them with a reducer, but is this likely to affect it's "sucking" capacity and/or flow? The pump will be below the bottom of the tank, however the fuel pickup is right on top, as usual.

Second option, the most expensive one I think... Run an electrical carb pump (£30) to a small swirl pot (£80) which has a 12mm outlet, 8mm feed and return, then add an EFI pump on the back end of this. I am sure this will work, and work well, but knocking on £200 is getting expensive, not to mention introducing 2 failure points.

Third option, this is quite a tall tank, though I'm not sat right in front of it at the moment, What about a V8 90 EFI fuel pump? How do these fit into the top of the tank? Is there a special ring for them to mount into which needs welding/brazing in place or would it be possible to just cut a hole with a hole saw, drop it in and self tapper it in place with a gasket? Or am I barking :) I'd rather not weld it as it has a small amount of the devils fuel still inside it :rolleyes:

If the above is true, I guess I can butcher a 90 V8 carb pump... a'la FF, I think? I now have 2 spare V8 EFI fuel pumps here, ready to butcher if I can :)

Any feedback gratefully received :)

Many thanks,


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I have run an external fuel pump with a reducer on a kit car. So far no problems.

The swirl pot method is excellent, but IMHO overcomplicated.

I'd recommend using an in-tank EFI pump. These can be easily extended to reach the bottom of the tank - I did this to mine before fitting to a series tank.

They are held onto the top of the tank by a ring and some bolts. I cut the ring from a RR tank and then welded onto the top of my series tank. Mind you, my tank was new, so no issues with welding it. Despite the issues with welding a fuel filled tank, I think this is probably the simplest (and cheapest) way to achieve what you want.

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OK, that sounds like we are getting somewhere, thanks chaps :)

Will probably visit a breakers today/tomorrow (if it ever stops raining :rolleyes: ) to see what they have kicking around, and see if I can get the ring off the tank at the same time -maybe hacksaw blade/battery drill time.....

As for welding it, I think I will try the water method, it will get rid of all that stinky diesel too :)

Will show the result when done, I've just finished stripping the OE EFI pump I have here on the shelf, there's really not much to it is there :)

*EDIT* Just a thought, if I cut out a ring from some 6mm plate, drilled and tapped to accept some ~M4 bolts this would work OK I presume?

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I use a RRC in tank EFi pump in my 110 for my 4.6 and not had any fuel starvation issues. (Apart from when the tank is empty... Which seems to be all too often...)

I put a new pump in when I replaced the tank so I didn't have to worry about pulling the tank out again for a while. Been good for 2 years now.

Works well and was simplest option for me.

I'd get the EFI pump fitment ring welded into your chosen tank (Part fill with water to weld and then drain and let drip dry for a few days in warm environment) , extend the pump pick-up to reach the bottom of the tank and off you go....


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I extended a RRC in tank pump to fit a 90 tank.

I avoided welding by making a ring nut from about 6mm plate and sawed a missing segment from it which allows it to be fed/fiddled into the tank through the hole cut for the pump. Hold the ring nut in plate with a length of stud on one of the threaded holes and then the pump can be positioned and the first couple of bolts put in and the stud wound out.

I already had the tank in the vehicle, half full of fuel as it had been running on carbs so i didn't want to water fill it to weld it

Edit: Didn't see your last post!

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Cool, lots of options, got a pump arriving tomorrow hopfully, so I can play :)

When I see exactly how it is designed to mount, I may be able to think something up which won't leak :)

Thanks guys!

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I have used both options, I have a custom made aluminium tank which uses a vauxhall cavalier fuel pump (Bosch) from the bottom of the tank. The tank has a internal baffle and is foam packed as well. total £120

The other tank is a modified series tank with a efi pump mounted into the top. (its for sale now as well!!) See picture attached, this prob cost 30 quid to complete.

post-2168-068030200 1294345887_thumb.jpg

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  • 3 weeks later...

WELL..... It's all done and dusted now :)

In the end I used the 'cut it from 6mm plate, drill, tap and weld in place' method, it has worked surpisingly well, though making the ring took a while due to the first one being too small (hole saw not big enough) and the second one needing fettling to get the pump to fit through -it makes for a pretty thin ring to get it all to bolt up.

The ring pre-fettling:


And on the fuel pump (still needed more fettling once I had extended the pump):


You will notice this is the earlier Rangie fuel pump, with only one fuel attachment, unlike the later with the sender and return included in the same unit, this makes it much easier to fit and also extend, and as I already had a pickup, return and breather pipe in the fuel tank, I had no need for another return. To extend I used a piece of ~2mm aluminium plate cut in a thin strip which I trimmed to fit well into the wide c-section bits which originally hold the pump together, this was plenty rigid enough. The extend the fuel pump outlet I just used some 8mm HP fuel hose and two petrol pipe clips, which is all that holds it together originally. :)

I MIG'ed the ring in place slowly with the tank half full of water, welding 6mm to ~1.6mm steel takes patience, but it doesn't leak ;)

Before bolting the pump down with 5 * M5 stainless bolts I put plenty of silicon around the mating surfaces to ensure a leak free seal. If I had had some ~ 2mm cork gasket I would have used that, but I didn't, so I didn't :)

I've not got a photo of the extended pump, sorry :( Hope the above description is enough.

Took about half a day, annoyingly long, but it is at least done and she runs again!

Thanks for your help peeps :)

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