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Fuel Pump Calculator

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How does a fuel pump work?How to choose a fuel pumpHow to use our fuel pump calculatorFAQs

If you need the right fuel pump for your engine, our fuel pump calculator is here to help! Just enter your engine's specifications, including horsepower, induction type, and fuel type, to find the perfect device for your vehicle. Whether you have a stock car or one with a modified powerhouse, our tool ensures you get a pump and fuel injectors that match your engine's needs.

Read the article below to learn more about fuel pump flow rate, fuel injectors, and how to choose a fuel pump.

How does a fuel pump work?

A fuel pump is like a dedicated delivery system for your car's engine. Its job is to make sure the engine gets the fuel it needs to run. Here's how it works: the fuel pump is usually located in the fuel tank. It sends fuel from the tank to the engine. Once there, the fuel mixes with air and powers the engine.

Think of the fuel pump as a heart pumping blood — but instead of blood, it's pumping fuel. Modern cars use electric fuel pumps, which are more efficient and reliable. They need a bit of electricity to work, but they play a crucial role in keeping your car going. Without the fuel pump, the engine wouldn't get its necessary fuel and would simply not run. As your car ages, parts like the fuel pump wear out, and its value decreases. Check out our car depreciation calculator to verify your car's current market worth.

How to choose a fuel pump

Selecting a proper fuel pump is extremely important for your car's performance, especially if it's been modified. That's why we created this fuel pump calculator. If the fuel pump in your stock car breaks down, the simplest approach is to perform a fuel pump replacement with the original model or one that closely matches it. This ensures compatibility and maintains the car's factory specifications.

However, the scenario changes if you've modified your engine. In such cases, choosing the correct fuel pump requires an individual approach, and this is where our fuel pump calculator comes in handy.

Several factors influence the choice of a fuel pump:

  • Power Output — The more horsepower your engine produces, the more fuel it requires. A higher-performance engine needs a pump that can deliver fuel at a rate that matches its power output.

  • Induction Type — Whether your engine is naturally aspirated, turbocharged, or supercharged affects your fuel pump choice. Turbocharged and supercharged engines, which force more air into the combustion chamber, typically require more fuel under higher pressure than naturally aspirated ones.

  • Fuel Type — Different fuels like petrol, methanol, or ethanol blends have different requirements. For instance, engines running on ethanol-rich fuel often need a more robust fuel pump due to ethanol's lower energy content and higher consumption rates.

  • Base Fuel Pressure and Boosted Fuel Pressure — These are important, especially for turbocharged or supercharged engines. Base fuel pressure is the standard pressure at which your fuel system operates without additional boost. However, when you add a turbocharger or supercharger, the engine requires a bigger fuel pump and fuel injectors.

Based on all of these, we can determine the fuel pump flow rate — how much fuel the pump can deliver to the engine. With this information, we can select the right device so you can perform a fuel pump replacement!

💡 If you're yet to modify your car, check out our turbo size calculator and boost horsepower calculator to determine what modifications to make and how much power you can expect from implementing them.

How to use our fuel pump calculator

Choosing the right fuel pump is made easy with our fuel pump calculator. Values are split into two sections; just input data and see the results. The first section focuses on the flow rate:

  1. Power — Input the power of your engine. You can switch between horsepower (both imperial and metric) and kW.

  2. Induction type — Select from naturally aspirated (0.3735 multiplier), turbocharged (0.415 multiplier), or supercharged (0.498 multiplier). Boosted engines need more robust pumps.

  3. Fuel type — Choose between Petrol, Ethanol E30, Ethanol E85, or Methanol.

  4. Flow rate — The calculator gives the flow rate of the required fuel pump. Use this value to determine which fuel pump to buy!

For example, to determine the necessary fuel pump flow rate for a 400 hp supercharged engine, multiply the horsepower output by 0.498. This results in a flow rate of 199.2 L/hr.

The second section focuses on pressure:

  1. Base fuel pressure — Input the correct value.

  2. Boost pressure — For turbocharged or supercharged vehicles; use 0 for naturally aspirated.

  3. Fuel system type — Select "Return" or "Returnless". Return systems cycle unused fuel back to the tank, whereas returnless systems regulate fuel pressure directly at the pump.

  4. Fuel pump pressure — This result indicates the pressure your fuel pump needs to handle. Use this value to determine which fuel pump and fuel injectors to buy!

For example, to calculate the required fuel pump pressure for a return-type fuel system, simply add the base fuel pressure to the boost pressure. This will give you the fuel pump pressure, measured in the same unit.

Now that you know how to choose a fuel pump and how does a fuel pump work, you can order the correct part and start working on your car! Remember that a bigger fuel pump will influence your vehicle's fuel consumption. Check out our fuel consumption calculator to see the difference.


How do I replace a fuel pump?

Replacing a fuel pump involves a few key steps:

  1. Safety first — Disconnect the car battery.

  2. Access fuel pump — Typically located in the fuel tank, access it (often under the back seat or trunk).

  3. Remove old pump — Carefully disconnect and remove it.

  4. Install new pump — Replace with the new pump, ensuring all connections are secure.

  5. Reconnect battery — Test the new pump.

Where is the fuel pump in a Ford Focus?

In a Ford Focus, the fuel pump is usually located inside the fuel tank. You can typically access it by removing the rear seat or through an access panel in the trunk, depending on the model year of your Focus.

What does a fuel pump do?

A fuel pump's job is to send fuel from the tank to the engine. It's a necessary part of the system, as it ensures that the engine gets the right amount of fuel it needs to run properly and power your car.

How to choose a fuel pump?

To choose a fuel pump, follow these steps:

  1. Check original pump — If possible, select a replacement that matches your original fuel pump's specifications.

  2. Flow rate and pressure — If the original isn't an option, pick a pump based on fuel flow rate and pressure requirements.

  3. Compatibility — Ensure it's compatible with your vehicle.

What fuel pump flow rate is needed for a 300hp turbocharged petrol engine?

For a 300 hp turbocharged petrol engine, the fuel pump should deliver approximately 124.5 liters per hour (32.9 US gallons per hour).

To calculate this yourself, multiply the amount of horsepower (300 hp) by a multiplier (0.3735 if naturally aspirated, 0.415 if turbocharged, 0.498 if supercharged), which gives you the required flow rate in liters per hour.



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