Fuel Tank Interchangeability 124 Spider

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Fuel Tank Interchangeability 124 Spider

Post by fp55scca » Fri Dec 07, 2018 6:55 pm

--Ok guys, can I use an early (say '71-'78), non-fuel injected fuel tank in an '81 fuel-injected Spider? Other than the fuel hose size on tank output of the fuel injected Spider, is there any reason an early tank could not be used?
Jim Scurria
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1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 Fiat 124 Spider
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Re: Fuel Tank Interchangeability 124 Spider

Post by rridge » Fri Dec 07, 2018 9:14 pm

The FI pump requires a gravity feed. The FI tank outlet is on the bottom to provide that feed. Auto Ricambi has new rust-free baffled FI tanks for less than $200 though you would probably need an FI tank gas gauge pick-up as well.
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Re: Fuel Tank Interchangeability 124 Spider

Post by vandor » Fri Dec 07, 2018 11:51 pm

What he said. Carbed tanks have no fuel output, that is handled through the fuel sender. FI thanks have a ~1/2" output and ~5/16" inlet nipples on the right front corner, by the spare tire.
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Re: Fuel Tank Interchangeability 124 Spider

Post by fp55scca » Sat Dec 08, 2018 8:33 am

--Ah, thanks guys! This tank issue is for a "parts car" that I am just playing with (and enjoying) until I cannibalize the engine and transmission, both of which run beautifully! The body of the car is pretty much Swiss cheese, otherwise, I would most certainly put a new AR tank in it! So I guess the lesson learned here is a FI tank can be used for a carb'd application, but a carburetor-tank not so much for a fuel injection setup?

--Then just for discussion purposes, if gravity feed to the high pressure FI pump is the issue, what if I ran a low pressure electric fuel pump next to an early, non-gravity feed tank? The only purpose of the low pressure pump would be to prime the high pressure FI pump? An ON/OFF switch could even be used on the low pressure pump, because I think the FI pump would be self-sustaining once started? Thoughts?
Jim Scurria
Norfolk, VA

1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 Fiat 124 Spider
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Re: Fuel Tank Interchangeability 124 Spider

Post by friedman » Sat Dec 08, 2018 8:54 am

Wouldn't an FI fuel pump provide enough suction to pull fuel from a carbed tank....Just like a Facet cube pump pulls fuel for a carb?

Jim, you so bored from racing that you are playing with a holy spider? What's wrong with your white street hooligan?
Carl in Virginia
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Re: Fuel Tank Interchangeability 124 Spider

Post by rridge » Sat Dec 08, 2018 9:04 am

Jim wrote:
if gravity feed to the high pressure FI pump is the issue, what if I ran a low pressure electric fuel pump next to an early, non-gravity feed tank? The only purpose of the low pressure pump would be to prime the high pressure FI pump?
I think that might work. I used to use a simple Facet cube mounted outside the tank but in series with the in-tank pump on my E-type and it was capable of pulling enough gas through the often failing Lucas pump to feed three SU carbs and simply drop off line when not needed. When I heard the clicking of the Facet cube I knew it was time to do battle with the prince of darkness once again.

The fuel pressure regulator on the L-Jetronic fuel rail controls and limits total pressure to the injectors by simply returning excess flow to the tank. Think about how the return flow would be handled at the tank.
Richard
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Re: Fuel Tank Interchangeability 124 Spider

Post by fp55scca » Sat Dec 08, 2018 9:25 am

--Good morning Carl! Believe it or not, I was supposed to be racing this weekend at VIR in Danville, VA. (a make-up race for the annual Prod-Fest normally run in Oct., but cancelled due to hurricane Michael.) But, weather forecast this weekend at VIR is supposed to be wet and cold (snow), so I bowed out. I can do cold just fine, but wet and cold, not so much!

--You might like my temporary ratrod project. Were it not for heavy duty floor mats, it would be a Fred-Flintstone-mobile. I have to be careful in the rain, it takes on water! The hood fell off, so I replaced it with an old fiberglass race one; and it needed a top, so it got a Pininfarina top temporarily. The Pinin top is getting restored to go on my '74, which is slowly making progress as a CSA replica (although not a faithful one).
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Jim Scurria
Norfolk, VA

1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 Fiat 124 Spider
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Re: Fuel Tank Interchangeability 124 Spider

Post by fp55scca » Sat Dec 08, 2018 9:43 am

rridge wrote:
Sat Dec 08, 2018 9:04 am
The fuel pressure regulator on the L-Jetronic fuel rail controls and limits total pressure to the injectors by simply returning excess flow to the tank. Think about how the return flow would be handled at the tank.
------------------------------------------
--Richard, the early carb tank has a fuel return provision through the sending unit, and I would think that would work just fine?
Jim Scurria
Norfolk, VA

1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 Fiat 124 Spider
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Re: Fuel Tank Interchangeability 124 Spider

Post by fp55scca » Sat Dec 08, 2018 10:38 am

rridge wrote:
Fri Dec 07, 2018 9:14 pm
.....Auto Ricambi has new rust-free baffled FI tanks for less than $200 though you would probably need an FI tank gas gauge pick-up as well.
---------------------------------------------------
--Richard, just a side note for info, you can use a non-FI sending unit with a FI fuel tank and setup. You just need to close-loop the two ports on the sender with a short section of hose.
Jim Scurria
Norfolk, VA

1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 Fiat 124 Spider
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Re: Fuel Tank Interchangeability 124 Spider

Post by fp55scca » Sat Dec 08, 2018 8:03 pm

--Ok men (and ladies), here's my report on fuel tank interchangeability:

--1981 Fiat 124 Spider, FI, all original equipment as best I can tell. Fuel tank was leaking badly. Previous owner had attempted to repair and re-seal it, but it only lasted a few months for me.

--I replaced the OE FI fuel tank with a used one from a 1972 124 Spider [one of the last series to have a drain plug in the bottom of the tank]. I've probably had the '72 tank on the shelf for maybe 15 years. It's in excellent condition.

--I made a 1/2" to 5/16" brass coupling (Home Depot - plumbing) to adapt the half-inch FI hose to the early tank fuel port on the fuel quantity sender. The return fuel hose attached directly to the fuel sender port.

--I elected not to install a low pressure pump (as we had discussed), just to see what would happen. The car starts and runs like normal. I'll update if anything changes.
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Jim Scurria
Norfolk, VA

1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 Fiat 124 Spider
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