12 replies to this topic

[Kjbfabrications]

Hello got a mpi want to fit right side tank too . Anyone done this ? Got a diagram on how to pipe it up ?

[Kjbfabrications]

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[mini13]

I messed around with twin tanks and injection, i found that having feeds and rreturns  in bith tanks caused issues, on tank would drain and fill the other slightly, to the point where at about 1/4 full on tank would start sucking air...

in then end I just returned to one tank, and had a T'd feed from both, thta worked... bit with the MPI tank... I would look at just adding a pipe into the bottom of the MPI tank, and connect that to the RH tank to balence the fuel, and just let the MPI feed and return do their thing.

[whistler]

I just bought the RH Tank fitting kit from Minispares. Easy. Onlt mod I did wasa to add a motorcycle fuel tap to isolate the RH tank if I needed to.

[Kjbfabrications]

I just bought the RH Tank fitting kit from Minispares. Easy. Onlt mod I did wasa to add a motorcycle fuel tap to isolate the RH tank if I needed to.

So how have u joined them ?

[Kjbfabrications]

I messed around with twin tanks and injection, i found that having feeds and rreturns  in bith tanks caused issues, on tank would drain and fill the other slightly, to the point where at about 1/4 full on tank would start sucking air...

in then end I just returned to one tank, and had a T'd feed from both, thta worked... bit with the MPI tank... I would look at just adding a pipe into the bottom of the MPI tank, and connect that to the RH tank to balence the fuel, and just let the MPI feed and return do their thing.

Was thinking new 8mm at the bottom of main mpi tank then that goin to the bottom of the right side tank . Return just to the mpi tank . Both breather T pieced together . No return to right side tank tho ? Or Return to both tanks ?

[mini13]

yeah, that sounds good.

slightly different to mine as I'm using two 5.5 gal tanks and external pump, but you way will be much neater.

8mm will be plenty, for just balancing the fuel, adding the fitting s will be the tricky bit.

[nicklouse]

Yes return to MPi side only. I would not connect the breathers. 
 

maybe fit a tap in the joining pipe.

[Ethel]

Wonder if you could use the fuel return to automatically prime a syphon from the reserve tank?

 

Regular reserve outlet tee'd in to the return for some Bernoulli action, likely to need a one way valve so the reserve don't syphon off the pump tank instead.

[nicklouse]

Wonder if you could use the fuel return to automatically prime a syphon from the reserve tank?

 

Regular reserve outlet tee'd in to the return for some Bernoulli action, likely to need a one way valve so the reserve don't syphon off the pump tank instead.

Seen that used to help empty both sides of a tank with two lower areas, like on a AWD or a car with an exhaust under the tank. But those can overflow back into themselves.

 

Not sure I would want it on a twin tank set up. But an interesting thought.

[Ethel]

Yes, hard to imagine why you'd do it. Perhaps if you really wanted to avoid adding a connection to the bottom.

[Bobbins]

I’m in the process of doing this to my JDM (SPi) Mini. After a lot of research I’ve concluded that the simplest method is to plumb both tanks together across the bottom (8mm / 5/16 hose) and to connect the RH tank breather to the original tank breather using a T-piece. I’ll also be fitting a fuel tap to isolate the RH tank.

The RH tank must have a breather otherwise it won’t function, but that breather needs to be connected to the original tank breather to ensure a ‘sealed’ system is maintained.

I’ve fitted a Minispares RH tank but it’ll need the filler neck removing and re-welding before my final fit because the angle is completely wrong, no surprises there.

Also be aware that the boot contact-switch is a very tight fit with the RH tank. Mine has the switch bracket but no switch fitted and I had to bend the bracket out a little to give more clearance. With a switch fitted it might need a rethink.

[timmy850]

One thing to note with twin tanks is that if you park on a side to side slope with near full tanks it’ll transfer fuel to the lower tank to level out the system. It can possibly over fill the lower tank. The factory got around this on early cars by piping the breather lines across the parcel shelf to drain on the opposite side. This might not be an issue with a sealed injection system, but worth thinking about