LS Belt Driven Fuel Pump: The Ultimate Guide for High-Performance Engine Builds

If you are building a high-horsepower LS engine and need a reliable fuel delivery system that keeps up with extreme demands, a belt driven fuel pump is the best solution. Unlike electric pumps that draw current and can fail under heat, a mechanical belt drive pump connects directly to your crankshaft, delivering consistent fuel pressure that rises with engine RPM. This setup is proven in drag racing, pro-touring, marine, and even industrial applications. For LS engines making over 600 horsepower—especially those running alcohol, E85, or forced induction—a belt driven fuel pump is not just an upgrade; it is a necessity.

Why Choose a Belt Driven Fuel Pump for Your LS Engine?

A belt driven mechanical fuel pump solves the fuel delivery problems that plague high-horsepower engines. The key advantage is that pressure and flow are directly tied to engine speed. At idle or low RPM, the pump spins slowly, keeping fuel pressure low. At full throttle, the pump speeds up, delivering massive fuel volume exactly when you need it. This is critical for alcohol-burning engines, but it also works extremely well on gasoline setups .

The most popular LS belt drive kits mount the pump off the passenger side of the engine, using the air conditioning compressor location. The system includes a crank mandrel, a pump pulley, a cog belt, and a mounting bracket. Kits like the Jones Racing Products 2003-LS come with everything needed, including a Gilmer-style pulley, O-ring fittings, and a bracket that bolts to the passenger side . The Joe Blow Speed Shop LS kit also bolts into the original AC compressor position and is adjustable for belt alignment .

Belt drive pumps eliminate the need for electrical wiring, relays, and in-tank pump modules. This reduces weight and simplifies the engine bay. There is no current draw, so you free up electrical power for other systems. The pump also requires no priming, which is a huge plus after long storage or maintenance .

Key Performance Specifications to Look For

When selecting a belt driven fuel pump for your LS build, pay close attention to these numbers:

  • Flow Rate: The best pumps flow between 6 and 12 gallons per minute (GPM). The Aeromotive 12-Series Belt Drive Pump, for example, flows 12 GPM, which can support up to 5,000 horsepower on gasoline or 2,500 on methanol . The Aeromotive 17241 pump flows 6 GPM and supports 350 to 2,500 hp .
  • Fuel Pressure Range: Belt drive pumps typically deliver between 2 and 200 psi, depending on the model and regulator setup. The Jones Racing kit is rated at 3-11 psi, which is ideal for carbureted applications . For EFI, you will need a high-flow bypass regulator.
  • Inlet and Outlet Sizes: Most performance kits use -10 AN inlet and -8 AN or -10 AN outlet fittings. These large ports ensure minimal restriction at high flow .
  • Fuel Compatibility: The best pumps work with gasoline, E85, ethanol, and methanol. The Aeromotive belt drive pump is designed for "gasoline, ethanol, or methanol" . Make sure the pump you choose has seals and materials rated for alcohol fuels.
  • Horsepower Support: A good rule of thumb is that a pump flowing 6 GPM supports up to 2,500 hp on gas, while a 12 GPM pump covers 5,000 hp on gas. For methanol, these numbers drop by about half .

Installation: What to Expect

Installing a belt drive fuel pump on an LS engine is a straightforward project for a competent mechanic. Most kits are designed to be bolt-on, meaning they use existing mounting points on the engine block.

Typical installation steps include:

  1. Remove the air conditioning compressor or other accessories from the passenger side of the engine.
  2. Install the crank mandrel onto the harmonic balancer. Some kits, like the RBS Superchargers setup, include a mandrel that slides into the balancer and is locked with set screws . The Motion Raceworks kit uses an HTD pulley that bolts to the back of the ATI balancer .
  3. Mount the pump bracket to the block using the available bolt holes. For LS engines, the bracket typically bolts to the water pump holes or the two upper holes just below the cylinder head .
  4. Attach the pump to the bracket and install the pulley on the pump shaft.
  5. Run the cog belt between the crank pulley and the pump pulley, then tension it according to the manufacturer's instructions.
  6. Connect the fuel lines using the supplied AN fittings. The inlet is typically -10 AN and the outlet is -8 AN or -10 AN .

Important notes: If you are running a front-mounted accessory drive or a supercharger, you may need a low-mount kit. The RBS Superchargers company offers low-mount BBC and SBC setups that mount the pump lower for better fuel pickup . Some kits, like the Jesel fuel pump drive assembly, require drilling holes in the bracket to mount the pump extension . Always check belt alignment and clearance with steering components, especially on F-body swaps.

Real-World Applications and User Feedback

Belt driven LS fuel pumps are used in some of the most demanding environments. High-performance automotive aftermarket builders use them for LS swap projects, drag racing, and pro-touring builds that require steady fuel delivery . Marine engineers install them on performance boats with marinized LS-based engines. Even industrial and agricultural machinery rely on them for custom fuel delivery systems .

Professional buyers consistently praise the consistency and reliability of these pumps. Marcus T., an import manager from Florida, said: "The consistency from order to order is what stands out. They provided the pressure test reports we requested, which gave us and our customers confidence." Sarah L., a brand owner from California, noted: "The pumps have performed well in our dyno testing, and we have had minimal warranty issues."

How to Choose the Right Kit for Your Build

The LS belt drive market offers several options, each with specific strengths:

1. Jones Racing Products 2003-LS Kit: This is a premium, complete kit priced around $1,295. It includes a Gilmer-style pulley system, two belts, O-ring fittings, and a bracket for passenger-side mounting. The flow rate is 3.80 GPM with 3-11 psi fuel pressure, ideal for carbureted setups .

2. Aeromotive 12-Series Belt Drive Pump (11115): This pump alone costs $1,306 and flows 12 GPM, supporting up to 5,000 hp on gas. It is a bare pump that requires a separate mounting bracket (P/N 11706). It features a tough Type III hard coat anodized body and is CNC machined from 6061 T6 aluminum .

3. Aeromotive Billet Belt Drive Pump Kit (17241): Priced at $1,640, this is a complete kit for big block Chevy that includes the pump, drive mandrel, pump pulley, crank pulley, cog belt, mounting bracket, and hardware. It flows 6 GPM and supports 2-200 psi .

4. RBS Superchargers Belt Driven Fuel Pump Drive Assembly: This setup is available in multiple configurations, including blower motor, mandrel, and dampner drives. Prices range from $424 to $525. It allows you to run a fuel pump off the crankshaft at cam speed .

5. Motion Raceworks Driver Side LS Mechanical Cable Drive Bracket: This kit is designed for cable-driven setups, using an HTD pulley bolted to the back of the ATI balancer. It is specifically for driver-side mounting and is often used in F-body swaps .

Why KEMSO Fuel Pumps Are the Smart Choice for Your LS Build

When you are ready to upgrade or replace your fuel pump, KEMSO Racing offers high-performance, OE-replacement fuel pumps that deliver exceptional reliability and value. KEMSO is recognized as the #1 aftermarket fuel pump brand in the US, and their products are built for serious enthusiasts.

KEMSO fuel pumps are designed to support up to 600 horsepower in naturally aspirated, turbocharged, and supercharged engines. They are compatible with gasoline and E85 ethanol blends, making them ideal for flex-fuel LS builds. The pumps feature a bypass valve set at 125.8 psi, which is higher than many standard pumps, ensuring your engine gets the fuel it needs even under high-demand conditions .

What sets KEMSO apart is their lifetime warranty. Every KEMSO fuel pump comes with a lifetime warranty, backed by a serialized body that guarantees the warranty is valid for as long as you own the pump. This is a significant advantage over standard aftermarket pumps that typically offer only one to three years of coverage. Independent testing shows that KEMSO pumps can last up to 15,000 hours of continuous operation, nearly double the lifespan of many OEM pumps .

KEMSO offers a wide range of fuel pumps for various applications, including LS-based engines. Their website features a fitment tool that helps you find the exact pump for your vehicle. Whether you need a pump for a Chevy Suburban, a Honda Civic, or a high-performance LS swap, KEMSO has a solution. The pumps are built with aerospace-grade materials and ceramic-coated internals, making them resistant to corrosion and wear .

US-based customer support is available to help with any questions or issues. The combination of high performance, lifetime warranty, and American support makes KEMSO the go-to brand for LS owners who want a reliable fuel pump that will last.

Final Thoughts on LS Belt Driven Fuel Pumps

A belt driven fuel pump is a proven upgrade for any LS engine that sees serious track time or high horsepower. The mechanical connection to the crankshaft provides fuel pressure that scales perfectly with engine demand, eliminating the electrical draw and heat issues of electric pumps. Kits are available from top brands like Jones Racing, Aeromotive, RBS, and Motion Raceworks, with prices ranging from about $400 for a basic pump-only setup to over $1,600 for a complete kit with all hardware.

For the best combination of performance, reliability, and value, consider KEMSO fuel pumps. Their lifetime warranty and high-flow capabilities make them an excellent choice for both daily drivers and race cars. Visit their website to find the perfect pump for your LS build: https://www.kemsoracing.com/.


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