Fuel pump selection for LS based engines and EFI conversions

Choosing the right fuel pump for your LS engine install or EFI conversion.

One of the most common requests that we have come in is what electric fuel pump should be used in order to install an LS engine or to do an EFI swap. There are thousands of different fuel pump options when you look at factory fuel pumps, OEM replacements, aftermarket fuel pumps, high performance, E85 compatibility and high flow options.

So how can you figure out which is the best fuel pump for your LS swap or EFI install?

First, we need to determine your flow rate requirements and this is based on your horsepower goals and type of fuel used. If you recall from the article we wrote about hose size selection there is a formula you can use to determine the required fuel flow rate. That article can be found here. In the interest of saving you time we will showcase the most popular fuel pump options for LSx swaps and fuel injection installs and what HP they are capable of supporting including E85 compatibility.

Choosing an Inline fuel pump or an in-tank fuel pump – What is the best option?

Hot Rod fuel hose sells both in-tank and inline fuel pumps to support a number of different applications. Depending on the type of sending unit and tank or fuel cell you will be utilizing you may only have the option of running an in-line pump. If the horsepower level you are seeking will support an in-tank pump and you have that option we strongly recommend it.

Benefits of an In-tank fuel pump over an Inline fuel pump for LS engines & EFI

• In tank fuel pumps are considerably quieter, the sound they produce is muffled by both the fuel and the tank and therefore let’s you focus on the sweet exhaust note your engine produces.
• In tank fuel pumps operate at a cooler temperature as they are submerged in fuel in turn which helps to prolong the fuel pump life.
• The install appears cleaner and less fittings are needed on the fuel line.
• Low chance of cavitation (failure) of the pump due to constant fuel at the inlet of the pump (when using a baffled tank and a high enough fuel level)

Benefits of an inline fuel pump

• More install options for a wide variety of older vehicles and hot rods / street rods.
• On very High Horsepower applications it may be necessary
• Replacement of a failed pump can be completed more easily than in tank.

*Note when installing an inline fuel pump you should mount the pump as low as possible in order to reduce the chance of cavitation on the pump. As pumps are built to push fuel rather than pull fuel this helps to reduce the amount of work the fuel pump needs to do in order to get the fuel out of the tank.

Now that we have some background what fuel pump should I choose for my LS engine install or EFI swap?

Most LS engines operate at 58 PSI, as well the most popular EFI systems operate anywhere between 48 PSI and 58 PSI. The exception to this would be Gen V LS engines with direct injection which have a higher-pressure requirement. Always choose the proper fuel pressure regulator for your application. We have many different options that can be found here.

You will notice on the pumps below that those that are compatible with EFI have a lower HP rating compared with gasoline. The reason that this happens is that in order to produce an equal amount of energy or HP from E85 takes more fluid approx. 30% more for each unit of HP. All ratings are for naturally aspirated engines, boosted applications will have different flow requirements please contact us if you require a fuel pump for a boosted application.

550HP E85 – 650HP Gasoline (Naturally Aspirated)

Walbro GSL-392 In line fuel pump – the most common choice for factory LS swaps up to mild mod engines. 255L of flow and based off of the OEM design for corvette. Features 10mm x 1.0 inlet and outlets so be sure to grab the adapter fittings found on our website.

Walbro GCA-758 In Tank fuel pump – A widely universal in tank design based on a GM sending unit design. Is compatible with many different sending units across many different applications both factory and aftermarket. Conversion to Hot Rod fuel hose line and AN fittings will depend on the sending unit used please contact us and we will be happy to help you figure out which adapter fittings are needed. This pump features a 255L flow rate and is very popular for LS engine installs and EFI conversions.

750HP E85 - 950HP Gasoline (Naturally Aspirated)

Aeromotive 11569 – In Tank fuel pump – A great option for keeping a factory looking install using the OEM sending unit while supporting an increased flow rate to 340L. This pump follows the GM style design but still supports many different applications. A popular option for higher horsepower LS swaps and EFI installs.

Higher horsepower applications than this will need many more questions answered, we suggest you reach out and we would be happy to help you plan out your entire fuel system. As experts in the area of fuel delivery we would be happy to help you plan out your system from pump to rails. Contact us HERE

 As always Hot Rod fuel hose provides high quality hose, fittings, pumps, filters, and regulators for LS swaps, EFI conversions, and any other application where AN fittings and line may be used. Click below to check out all of our available products. 

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