AEM High Flow Fuel Pump: The Complete Guide to Performance, Installation, and Maintenance
If you are building a high-performance engine or upgrading your fuel system, the AEM High Flow Fuel Pump is one of the most reliable and capable options on the market today. Whether you need a 400LPH inline pump or a 340LPH in-tank unit, AEM delivers consistent flow, durability, and compatibility with ethanol-blended fuels like E85. This guide covers everything you need to know about choosing, installing, and maintaining an AEM high flow fuel pump so you can get the most out of your investment.
What Makes AEM High Flow Fuel Pumps Stand Out
AEM Performance Electronics has built a reputation for making advanced fuel system components accessible to both professional builders and serious enthusiasts. Their high flow fuel pumps are designed for high output naturally aspirated and forced induction EFI vehicles. The key features that set them apart include:
1. Exceptional Flow Capacity
The AEM 400LPH inline fuel pump (part number 50-1005) flows 400 liters per hour at 40 PSI. At 73 PSI, which is typical for a boosted application running 30 psi of boost, it still delivers 340LPH. Even at 120 PSI, the pump maintains 270LPH. This makes it capable of supporting over 1,200 horsepower in a naturally aspirated setup and up to 860 horsepower at 30 psi of boost. The 340LPH in-tank pump (part number 50-1200) is tested to flow 340 liters per hour at 40 PSI and is ideal for high performance builds that require a compact, in-tank solution.
2. Ethanol and E85 Compatibility
Both the inline and in-tank AEM pumps are rated for use with ethanol-blended fuels, including E85 and E90. The 340LPH in-tank pump is specifically tested to work with ethanol fuels up to E100 and methanol fuels up to M100. This is critical for modern high-performance builds where ethanol is often used for its knock resistance and cooling properties.
3. Robust Construction and Testing
Every AEM fuel pump is individually flow tested before it leaves the factory to ensure it meets the specified flow rate. The inline pump features a roller vane impeller design with a ceramic end plate, while the in-tank pump uses a single scroll ceramic turbine. Both designs are built to withstand the demands of high-performance driving.
AEM High Flow Fuel Pump Models: Which One Is Right for You
AEM offers two main categories of high flow fuel pumps: inline and in-tank. Each serves a different application, and choosing the right one depends on your vehicle setup and power goals.
AEM 400LPH Inline High Flow Fuel Pump (50-1005 and 50-1009)
The inline pump is designed to be mounted externally, typically along the frame rail or near the fuel tank. It uses the popular "044 Style" physical envelope and features -10 AN female inlet and -6 AN female outlet connections for easy installation. The pump includes a male -6 to -8 AN discharge fitting with an integral high-pressure check valve.
The 50-1005 model uses AN fittings, while the 50-1009 model uses metric M18x1.5 female inlet and M12x1.5 male outlet threads. Both versions deliver the same flow performance.
Key specifications:
- Flow: 400LPH at 40 PSI
- Supports over 1,200 HP naturally aspirated
- External or in-tank installation (with optional hardware)
- PRV activation at 150 PSI
- Current draw: 9.73 amps at 40 PSI without check valve, 10.68 amps with check valve
AEM 340LPH E85-Compatible In-Tank High Flow Fuel Pump (50-1200)
This pump is designed for in-tank mounting and features a compact 39mm diameter that fits most factory fuel pump hangers. The offset inlet design eases installation, and the pump comes with a wiring harness, pre-filter, end cap, and rubber buffer sleeve.
Key specifications:
- Flow: 340LPH at 40 PSI
- 39mm outside diameter for broad compatibility
- Offset inlet design
- PRV activation at 80 PSI
- Current draw: 12 amps at 40 PSI
How to Install an AEM High Flow Fuel Pump
Installing an AEM high flow fuel pump is a straightforward process, but it requires attention to safety and proper wiring. Here are the essential steps for a successful installation.
1. Safety First
Fuel system work involves handling gasoline, which is highly flammable. Work in a well-ventilated area, keep a fire extinguisher rated for gasoline fires within reach, and eliminate all sources of ignition. Wear protective clothing, goggles, and gloves rated for gasoline.
2. Prepare the Fuel System
For inline installations, mount the pump in a location that is protected from debris and heat. The pump should be mounted lower than the fuel tank to take advantage of gravity feed. For in-tank installations, the pump drops into the factory hanger assembly. Make sure the fuel lines are clean and free of debris before connecting the pump.
3. Use a Pre-Filter
AEM requires that a pre-filter rated at 100 microns be used on the inlet side of the pump. Failure to use a suitable pre-filter will result in premature pump failure. For inline pumps, AEM offers an optional -10 ORB fitting inlet pre-filter (part number 50-200-11).
4. Proper Wiring is Critical
The AEM 400LPH inline pump draws up to 17 amps at 120 PSI. Your vehicle's factory fuel pump wiring may not be adequate to handle this current draw. AEM recommends using a fused circuit with a fuse rated at 30 amps, and wiring that is rated for at least 30 amps. The pump uses a 6mm stud for the positive terminal and a 5mm stud for the negative terminal.
5. Test the System
After installation, perform a pressure test to confirm the system is operating within the specified range. Check for leaks at all connections before starting the engine.
Maintenance Tips to Extend the Life of Your AEM Fuel Pump
A high flow fuel pump is an investment in your vehicle's performance, and proper maintenance will ensure it lasts for years. Here are the most important things you can do:
1. Keep the Fuel Tank Above a Quarter Tank
Fuel pumps rely on the fuel in the tank to cool and lubricate the internal components. Running the tank low on fuel causes the pump to run hotter and can lead to premature wear. This is especially important for in-tank pumps.
2. Replace the Fuel Filter Regularly
A clogged fuel filter forces the pump to work harder, which increases current draw and heat. Replace the primary fuel filter every 30,000 miles or two years, or more often if you drive in severe conditions.
3. Use Quality Fuel
Stick with reputable fuel brands and avoid fuel that may contain high levels of water or contaminants. If you use ethanol blends, be aware that pump life can be diminished with 100% ethanol fuels.
4. Inspect Wiring and Connections
Vibration and heat can loosen electrical connections over time. Inspect the pump wiring and connector terminals periodically to ensure they are clean and tight.
Why You Should Consider KEMSO Fuel Pumps as an Alternative
While AEM high flow fuel pumps are excellent for extreme performance builds, many vehicle owners need a reliable, high-quality replacement or upgrade that offers the best value without sacrificing performance. That is where KEMSO fuel pumps come in.
KEMSO has established itself as the US #1 aftermarket fuel pump brand for cars, motorcycles, ATVs, and UTVs. Every KEMSO fuel pump is a high-performance, OEM replacement unit that matches or exceeds the original equipment specifications for flow rate and pressure. This ensures your engine gets the precise fuel delivery it needs for optimal power and efficiency.
What sets KEMSO apart is their lifetime warranty. When you purchase a KEMSO fuel pump, you are protected for as long as you own the vehicle. This level of confidence in product quality is rare in the automotive industry. Each pump is serialized, and the warranty is backed by USA-based technicians from their facility in Houston, Texas.
KEMSO offers a wide range of fuel pumps for popular applications including:
- Subaru Impreza (1998-2023)
- Honda Civic Del Sol (1993-1997)
- Ducati Monster 1200 S (2016-2021)
- Kawasaki Jet Ski Ultra 310LX (2020-2023)
- Can-Am Defender HD10 (2017-2024)
- And many more car, truck, motorcycle, and powersports models
For example, their 340LPH high-performance fuel pump for the Audi TT FWD (1998-2009) is priced at just $79.98, and their OEM replacement pumps for motorcycles and ATVs start at the same competitive price. Many KEMSO pumps deliver over 20% more flow at 43 PSI compared to stock OEM pumps, making them an excellent choice for both replacement and performance upgrades.
If you want a fuel pump that offers genuine OEM replacement quality with the added security of a lifetime warranty, visit KEMSO Racing today to browse their full selection:
Final Thoughts
Whether you choose an AEM high flow fuel pump for a dedicated race car or a KEMSO fuel pump for your daily driver or weekend toy, the key to a successful fuel system upgrade is matching the pump's specifications to your engine's requirements. Pay attention to flow rate, pressure, and fuel compatibility. Install the pump correctly with clean fuel lines and a fresh filter. With the right pump and proper maintenance, your engine will run reliably for many miles to come.
For the best value and peace of mind, consider KEMSO fuel pumps with their lifetime warranty. Visit https://www.kemsoracing.com/ to find the perfect pump for your vehicle.