Twin fuel tanks and injection

[John_S4x4]

Just a quick question. I have a car with twin petrol tanks running on carbs. At the moment, the tank outputs go into a Y adaptor with a single feed line to the carbs/pump. If I went for an injection setup, is there anyway to keep the tanks as is ? Can I have one tank for feeding the fuel rail/pump and the other for return, with some kind of Y adapter or balance/cross pipe. What's my best bet ? I don't want to change the tanks if I can help it. Cheers - John

[annodomini2]

Wouldn't it be better to compile the two feeds from the tanks into a Y piece which is fed into the fuel pump and have a single return pipe from the fuel pressure regulator to one tank, the y feed between the two tanks would then act as the balance pipe, an idea?

Should theoretically make the setup simpler.

[GreenV8S]

If you only have one outlet from each tank then I think you would need to connect the return between the Y piece and the pump inlet iywim. This isn't ideal because it means the same small amount of fuel gets recirculated round the fuel rail again and again until it gets used; better to dump it back into the tank and draw out some fresh cool fuel. You also need to be carefull about returning to one tank only, as the pump will then transfer fuel from one tank to the other rather quickly.

[eliot]

What about a swirl pot/surge tank ?

Existing low pressure tank feeds the surge tank, which feeds your efi pump. Fuel rail return goes into surge tank.

search under fuel @ www.msefi.com has been discussed as length.

(and on this forum and possibly under ultima also)

>> Edited by eliot on Monday 11th July 19:47

[steve_D]

Go look for the valves from an XJ6. They have a tank switchover which switches both the supply and return from tank to tank. All done with solenoid valves.
The switch also switches over the fuel level senders.

Yes this has been done on the Ultima forum and discussions on swirl pots with high and low pressure pumps.

Steve

[andygtt]

eliot said:

What about a swirl pot/surge tank ? Existing low pressure tank feeds the surge tank, which feeds your efi pump. Fuel rail return goes into surge tank. search under fuel @ <a href="www.msefi.com">www.msefi.com</a> has been discussed as length. (and on this forum and possibly under ultima also) >> Edited by eliot on Monday 11th July 19:47

this is what I would do.... the risk of any other route is that the feed is not of sufficient size to fuel the engine (by only using only one pipe you will effectivelly half the potential fuel flow from std).

You'd also need to ensure they were balanced otherwise you'd empty one and potentially fill the other.

[John_S4x4]

Thanks very much guys. I shall investigate a swirlpot for the return, fed by the single feed from the twin tanks. The petrol tanks are intergral to the car, and I would of have had to disc them out with a grinder.

[nel]

Silly question maybe, but are you sure that the two tanks are not linked by another crossover pipe apart from their outlet feeds? I thought that twin tank set-ups always had a crossover for level balancing purposes.