EFI in-tank fuel pump to carb?

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LowDeck451

LowDeck451

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Could a late 80’s early 90’s factory high pressure (40? 50? psi) FI fuel pump be regulated down to work with a carburetor (with a return line of course)? Reasons being factory pump reliability and quietness in a ‘74 D100 daily driver. Thanks.
 
Yes, I spoke to Aeromotive about this and they said you'd need a two stage regulator as it was too far of a leap to go from EFI pressures (50+ psi non-regulated pump pressure) down to 8psi or less as required for a carburetor with a single regulator. They also stated a larger return line would be needed, 3/8" minimum.

My specific question was using their Stealth II tank and a regulator. That when the -6 (5/16") return would be too small. The two stage regulators were over $300 so I stuck with a mechanical pump and factory pick up.
 
Thanks. Yeah, that’s interesting, but the reason I’m leaning toward a factory pump is reliability. I was hoping to use a tank and pump (new pump) from a late 80’s/early 90’s D150 in my ‘74 D100 since those trucks are so similar but, not sure if that’s a drop in deal though. Also, I’m hearing a lot about aftermarket pump failures, though these are the external pumps. My 2000 Ram has 293k miles on the original pump, which maybe is unusually good, but still...
 
My race car has a Aeromotive 2000 external fuel pump. It was sent to Aeromotive to be rebuilt cause the wiring fried. I then bought it from a friend. Like I said it was rebuilt to their factory specs. The very first time we turned it on it had 48 pounds of pressure. We could only turn it down to 8 psi. My Pro Systems carb works fine. Kim
 
YoloCtyFlash said:
Could a late 80’s early 90’s factory high pressure (40? 50? psi) FI fuel pump be regulated down to work with a carburetor (with a return line of course)? Reasons being factory pump reliability and quietness in a ‘74 D100 daily driver. Thanks.
Click to expand...
This was taken from Aeromotive website under frequently asked questions. This is going to be my setup once I finish the install. The last paragraph is the plan, I'm using my stock in tank pump, stock fuel lines on '89 D100 w/ 5.9 magnum swap. Can't comment on how it will work but will try it.

1. I want to convert my EFI engine to a carburetor, how can I “knock the pressure down” coming out of my EFI pump? What Aeromotive regulator should I use for this?

A common misconception about fuel pumps is that they “put out” a specific pressure. It makes more sense to think of the pump as a source of flow. A bypass regulator creates pressure by restricting flow from the pump, forcing the pump to produce pressure up to the regulator’s set point. Once enough pressure is created the regulator bypass is forced open, allowing excess flow onto the return line. From here the regulator relieves just enough excess volume to maintain pressure. The Aeromotive 13301 bypass regulator can bypass enough volume to handle most medium to larger in-tank EFI pumps, if the return line itself is large enough. Note: Most stock EFI return lines are too small for a carburetor conversion, creating more backpressure than the regulator. At minimum, carb conversions with a 13301 regulator will require a –06 AN (3/8″) return for small OE pumps and an AN –08 (1/2″) for medium to larger pumps. When in doubt install the larger, freer flowing AN -08 line to ensure good results.

If the return line is too small, the question becomes, “Besides running a bigger return line, is there any other way to use the stock, in-tank EFI fuel pump to feed a carburetor?”

There is one possibility, but it means adding another regulator, using both a bypass and a static regulator together. In this case the 13301 regulator is used to first control what is called “line pressure”. This means feeding the stock supply line into the 13301 and then running the stock return line from the bypass port back to the tank. Next, the outlet line from the 13301 is fed into the 13205 static regulator before going to the carburetor. The 13301 is set for 12-14 PSI, high enough to allow use of the smaller, stock return line and then the 13205 is used to block that down to the 5-8 PSI range for the carburetor.
 
rdunnam said:
This was taken from Aeromotive website under frequently asked questions. This is going to be my setup once I finish the install. The last paragraph is the plan, I'm using my stock in tank pump, stock fuel lines on '89 D100 w/ 5.9 magnum swap. Can't comment on how it will work but will try it.

1. I want to convert my EFI engine to a carburetor, how can I “knock the pressure down” coming out of my EFI pump? What Aeromotive regulator should I use for this?

A common misconception about fuel pumps is that they “put out” a specific pressure. It makes more sense to think of the pump as a source of flow. A bypass regulator creates pressure by restricting flow from the pump, forcing the pump to produce pressure up to the regulator’s set point. Once enough pressure is created the regulator bypass is forced open, allowing excess flow onto the return line. From here the regulator relieves just enough excess volume to maintain pressure. The Aeromotive 13301 bypass regulator can bypass enough volume to handle most medium to larger in-tank EFI pumps, if the return line itself is large enough. Note: Most stock EFI return lines are too small for a carburetor conversion, creating more backpressure than the regulator. At minimum, carb conversions with a 13301 regulator will require a –06 AN (3/8″) return for small OE pumps and an AN –08 (1/2″) for medium to larger pumps. When in doubt install the larger, freer flowing AN -08 line to ensure good results.

If the return line is too small, the question becomes, “Besides running a bigger return line, is there any other way to use the stock, in-tank EFI fuel pump to feed a carburetor?”

There is one possibility, but it means adding another regulator, using both a bypass and a static regulator together. In this case the 13301 regulator is used to first control what is called “line pressure”. This means feeding the stock supply line into the 13301 and then running the stock return line from the bypass port back to the tank. Next, the outlet line from the 13301 is fed into the 13205 static regulator before going to the carburetor. The 13301 is set for 12-14 PSI, high enough to allow use of the smaller, stock return line and then the 13205 is used to block that down to the 5-8 PSI range for the carburetor.
Click to expand...
That’s interesting, thanks!
 
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