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Discussion Starter #1
Anyone ever cut apart a Spica equipped vehicle's fuel tank ? I.E.- how is the fuel return line plumbed internally, or does it just dump back into the tank as soon as it passes through the tank wall ?
I'm contemplating an e.f.i. conversion to an originally carbureted vehicle tank and would prefer to keep it simple. Maybe even fabrication of an additional hose barb/elbow onto the original outlet/sender flange. Is there benefit to running the return line down into the tank and letting returned fuel out in the general area of the in-tank fuel pump and pickup that I intend to use in conjunction with an external pump ?
Anyone have experience with this ?
I have done a previous e.f.i. conversion to an original Spica GTV so the plumbing was simple. I did not use an internal supply pump- the stock external pump was perfectly adequate in 99% of situations.Suggestions welcomed...
 

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Discussion Starter #2
O.K.- let me ask a simpler question: who has converted a carbureted 105/115 Alfa to e.f.i. using the stock tank and how did you do it, please ?
 

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Discussion Starter #3
O.K.# 2- after a little web research I can answer one of my two above questions. Accepted industry wisdom/best practice is to plumb returning fuel back into the tank BELOW existing fuel level to prevent aeration of fuel. IOW, don't let it just cascade (pour) back into the tank as this causes all sorts of fuel pressure variations and thus drivability issues potentially due to that aeration. It is worth the extra time and effort to devise a way to introduce returned fuel below the existing tank fuel level. Makes sense to me.

I would still be interested in seeing what others have done to fabricate outlet and return systems for an e.f.I. conversion using a carb fuel tank.
 

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Discussion Starter #6
To clarify: I would like to see pictures and/or have a description of how you modified any model year carbureted 105 series fuel tank to be used in an e.f.i conversion, of any sort.
Spica tanks are easy, BTDT sucessfully. I want to know what you did when you ****canned the webers and adapted an electonic fuel injection system in your formerly carbuteted car. Please.
There are lots of posts regarding hardware used under the hood for intake, injectors, ignition, exhaust, etc. I want to know about the other end, I.E.- fuel tank fitting and plumbing, fuel pumps, fuel filters, the supply end of things using a non-Spica tank. Tanks in advance.
 

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SPICA injected cars have a vented gas cap. That prevents any sort of pressure buildup.
No they don't. The carb cars have vented gas caps. If Spica had vented gas caps there would be no need for the Evap system or the expansion tanks.
 
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I'm not sure about the fit of other FI tanks for your car but, (the tank opening should be the same.)
why not just buy a used/new one. If used, there are a lot of suppliers selling kits to clean and coat the tank in sides. On mine (Spica to Weber converted) the outlet is at the bottom front of the tank. (like the picture above) The fuel pump is near the outlet. You would have to source (APE) the parts to mount the pump but it will be safer and cleaner.
 

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Discussion Starter #11
Thanks all for the replies. Condition and availability of the tank in this case is not an issue, and yes the tank hole size and bolt pattern for the gauge sender/fuel pump unit !'are all identical, I think. Now that I have researched and determined the internal plumbing requirements the remaining fabrication job is to add a return line fitting and internal hose to an already very crowded flange. If anyone has done this I would love to see the results.
 

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Discussion Starter #13
Osso- thanks for the pix, hope you didn't go to all that effort just for me. Anyway, that's a drag about the failed tank liner material, if that 's what we're seeing. Also, not quite sure what I'm looking at in your second pic- don't recognize that opening. What tank in what car ?
Attached are some pix of the pieces and eventual complete assembly I cobbled together years ago for the twinspark into 74 GTV conversion I did. I never used it because the external supply pump worked great without an internal helper pump. This was on the stock, bottom outlet Spica tank. Look closely and see if you can identify why this particular orientation between outlet and float would not have worked very well. ;)
Doesn't appear as if there is enough room for adding another fitting for the return line beside the outlet though. :(
 

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