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Walbro Carburetor to EFI Conversion Fuel Pumps Kits
Choose from these Carb2EFI kits...
...or start by taking a quick course on EFI Fuel System Conversion!
Congratulations! Taking the step to move from carburetion to Electronic Fuel Injection (EFI) is commendable--and comes with some great rewards! But it does require some upgrades to be made to your existing fuel system. We are frequently asked what fuel pump and other components are required to make the carb to EFI switch. This page sets out to answer those questions and give you a one-stop shop to purchase the exact components you need to be successful!
How Do I Upgrade My Carburetor Fuel Pump?
The biggest difference between a fuel system for a carbureted engine and the fuel system for an EFI engine is the pressure. Most carburetors want about 2-4 PSI at the inlet. Any more than that will push the fuel right past the needle valve and flood fuel into the engine. To accomplish this, carbureted vehicles use a much lower-pressure pump (you'll need to change that) and a non-return style regulator (you'll need to change that too.) The non-return style fuel pressure regulator simply holds back whatever few pounds of excess pressure is supplied by the low-pressure fuel pump and only lets through what pressure is required by the carburetor.
How Much Fuel Pump Do I Need?
Set aside the question of pressure for a moment--we'll get to that. The question you need to ask at this point is, "How much fuel pump do I need?" That is based on the amount of horsepower you expect your engine to make. We offer EFI fuel pumps in several different flow ratings. These fuel pumps will feed different amounts of horsepower based on whether the vehicle is carbureted or uses force induction (turbo or supercharger) and the fuel that the engine uses (gasoline or E-85.) Here is a chart to give you an idea:
*All values shown for gasoline. Multiply by .72 to calculate the amount of horsepower supported when using E85.
Inline or In-Tank Pump?
When converting from carbureted fuel system to EFI fuel system, inline is generally the easy answer. Buy one of our inline EFI conversion kits, install the pump as close to the tank and as low as possible. Ensure that you install a filter before and after, and you are all set. You likely don't even need to drop the fuel tank!
However, some folks just aren't happy with inline fuel pumps and want to go in-tank. Maybe they need to run E85 (which is only compatible with the 450 LPH in-tank pump) or they need more than 255 LPH (the maximum individual inline fuel pump. In-tank pumps are, admittedly, a bit quieter (although the Walbro GSL-family of inline fuel pumps are remarkably quiet for performance fuel pumps.) In that case you need to be prepared to do a bit more engineering as a result of your choice. Our in-tank EFI conversion kits include a in-tank pump along with a sock filter. It is going to be necessary for you to use a wiring bulkhead (included in the kit) to provide you with power in the tank for the pump. Then, you are going to need to engineer some sort of holder to which to affix the fuel pump so that it stays firmly in place, upright and at the bottom of the tank. Consult a fabricator who has experience in this area if you have specific questions or need assistance.
What Fuel Pressure Regulator Do I Need?
(The answer is a little different if you are installing a low-pressure TBI system such as a GM TBI. For that answer, read What If I'm Running Throttle Body Injection?)
You will need a return-style fuel pressure regulator to deliver the correct fuel pressure to the engine. Those are readily available. We recommend the outstanding Holley HP EFI Adjustable Fuel Pressure Regulator. It is adjustable from 15 to 65 PSI.However, the intuitive reader will realize there is currently only one fuel line between the fuel tank and the engine compartment. That means that a second fuel line must be installed for virtually all EFI fuel system upgrades. It is not necessary for the line to be metal (as is the OE fuel line.) We recommend using a good quality EFI fuel hose that is available at any auto parts store. It is left as an exercise to the installer to determine the safest way to correctly secure the fuel line in place in a manner that ensures that it is not crimped or kinked. An abundance of cable ties fixing the hose to the OE metal line usually works well. Note that sometimes it is advisable to use the metal line as the return and the hose as the feed. This is particularly true when one is running an especially-high horsepower engine and might be feeding two or even three fuel pumps into a single line. In this case, source a larger hose to accommodate the large amount of fuel that will be needed.
Where Do I Return Fuel To The Tank?
The fuel tank that was installed in your carbureted vehicle likely made no provision for fuel return. That being the case, this is another opportunity for you to be creative. Many tanks have a vent that has been used by some installers to attach the return line. We don't have enough experience to either confirm or deny the efficiency of that method. However, on all of our kits we offer the option of ordering a fuel line bulkhead. This allows you to drill a hole in the top of the tank and insert through that a hose barb fitting. The bulkhead fitting includes washers for both sides of the fuel tank and should provide perfectly for your requirements.
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