Fuel Injection Vs Carburetor: Performance And Efficiency

Carburettors and fuel injection systems are the primary ways to deliver fuel to an engine. Carburettors were the most common method until the 1980s and 90s when fuel injection systems became more popular. Fuel injection systems use an electronically controlled system to regulate the fuel-air mixture, while carburettors are mechanical devices that do not rely on electronics. This means that fuel injection systems can offer more power and better fuel efficiency than carburettors.

Characteristics of Changing from Carburetor Feed to Fuel Injection

Fuel injection systems are more fuel-efficient

Fuel injection systems use an electronically controlled system to regulate the fuel-air mixture, achieving the correct stoichiometric ratio. The stoichiometric ratio is the ideal ratio of air to fuel for maximum engine efficiency. For gasoline, this ratio is about 14.7:1. By maintaining this ratio, fuel injection systems ensure that fuel is used efficiently, leading to improved fuel economy.

The precision of fuel injection also results in more complete combustion. This means that the fuel is burned in a cleaner way, leading to fewer pollutants and improved emissions. Additionally, fuel injection systems do not need to be tuned like carburetors, reducing the maintenance required and further contributing to their fuel efficiency.

The benefits of fuel injection systems over carburetor feed systems extend beyond just fuel efficiency. Fuel injection systems provide higher power and torque, improved reliability, and better performance. The accuracy of fuel injection and modern electronic controls ensure that fuel delivery matches driver demand, offering more precision than carburetors. Sensors in fuel injection systems can account for changes in air or fuel temperature and atmospheric pressure, resulting in improved overall engine performance.

Converting from a carburetor to a fuel injection system can be a complex process, but it offers significant advantages in terms of fuel efficiency and performance. It is a popular custom project for classic car owners who want to improve their vehicle's fuel economy and power while retaining its classic look.

They provide more power

Fuel injection systems provide more power than carbureted engines. The main reason for this is the level of control that fuel injection systems have across the engine's operating range. While carbureted engines may be accurate in one spot, they can be off in others. Fuel injection systems, on the other hand, have precision across the entire powerband, resulting in significantly better and more consistent performance.

Fuel injection systems inject the proper amount of fuel required for the air being ingested by the engine, resulting in better fuel efficiency, more horsepower, and torque. This is because fuel injection systems use an electronically controlled system to regulate the fuel-air mixture, achieving the correct stoichiometric ratio. Carbureted engines, on the other hand, are mechanical devices that do not rely on electronics to mix air and fuel.

The accuracy of fuel injection and modern electronic controls lead to fuel delivery that matches driver demand. This offers more precision than a carburetor, as sensors in a fuel injection system can account for changes in air or fuel temperature or atmospheric pressure. The ECU has the ability to measure engine load and make fuelling changes based on elevation. This means that fuel injection systems can provide more power and torque than carbureted engines, resulting in improved performance.

Another benefit of fuel injection systems is the ease of use. Adjustments can be made without fetching a screwdriver, and changes can be made while driving. This level of control and precision is not possible with carbureted engines, which is why fuel injection systems provide more power.

They are more reliable

Fuel injection systems are more reliable than carburetor feeds. This is because they maintain an optimum air-to-fuel ratio, eliminating random engine stoppages and oiled spark plugs. Fuel injection systems also account for cold and hot starting performance by calculating the optimum air-fuel mixture based on the exact conditions. This means that when you turn the key, the car is going to start.

Fuel injection systems are also self-tuning, which means that less maintenance is required. They can constantly tweak the balance depending on the engine's needs, resulting in less wasted energy and better fuel efficiency. This also means that you get complete combustion, so fuel is burned in a cleaner way, leading to fewer pollutants.

The ECU in a fuel injection system has the ability to measure your engine load and make fuelling changes based on the elevation you're at. This means that the engine will start anywhere, from Antarctica to the middle of the desert.

The ability to inject the proper amount of fuel required for the air being ingested by the engine is another key advantage. Proper mixtures at all engine loads result in better fuel efficiency, more horsepower and torque, and cleaner tailpipe emissions.

The ease of use is also a factor in reliability. As Holley EFI engineer, Matt Lunsford, says: "You don't have to fetch your screwdriver to make an adjustment, and the sky's the limit on what you can change... and the computer can make changes as-needed while you're driving down the road."

They are easier to start

Fuel injection systems are easier to start than carburetor-fed engines. This is because fuel injection systems are less sensitive to changes in weather conditions. They calculate the optimum air-fuel mixture based on the exact conditions, ensuring the engine starts when you turn the key. Carburetor-fed engines, on the other hand, are more sensitive to weather changes, which can make starting the engine more difficult.

The process of converting from a carburetor to fuel injection can be done in a few steps. First, you'll need to remove the air-cleaner housing and set it aside. Label and remove all vacuum lines and wires connected to the carburetor. Disconnect the throttle linkage and fuel supply, and remove the nuts securing the carburetor to the intake. Lift the carburetor off and set it aside to drain. Keep any linkage brackets in their original locations. Clean the intake-mating surface and install a new carburetor-flange gasket, followed by the new EFI unit. Tighten the nuts evenly, ensuring the throttle linkage opens and closes freely. Reconnect the throttle linkage, transferring any required hardware from the carburetor.

The next step is to install the oxygen sensor bung by drilling a hole after the point where the individual pipes join. This hole must be above the horizontal to prevent condensation damage to the oxygen sensor. Weld the bung securely and install the sensor once it cools. Alternatively, if you don't have a welder, you can cut the exhaust pipe and replace it with an O2 sensor reducer. Ensure your exhaust system has no leaks, or your new fuel injection system may not work properly.

Connect the vacuum lines and install the coolant temperature sensor by wrapping it with Teflon tape and placing it near the thermostat housing. Connect the fuel lines, and remove and block off the stock mechanical fuel pump, as it won't supply the required pressure for the fuel injectors. Mount and wire the control/power module, ensuring it's not near major sources of heat and that the wiring is routed through the firewall/bulkhead using grommets for protection.

Finally, finish wiring the TBI unit, connecting the handheld controller to the power module. Verify that all wiring and fuel connections are correct, turn the ignition to the "Run" position, and listen for the fuel pump to start. Perform the initial configuration, setting the engine displacement, number of cylinders, camshaft selection, fuel pump type, target idle speed, and timing control. Adjust the throttle blades, and you're ready to start your newly fuel-injected engine.

They are better for the environment

Carburetor-fed engines have been largely replaced by fuel injection systems, which deliver fuel to the engine cylinders with more control and precision. This increased precision results in better fuel efficiency, which helps drivers save money at the pump.

Fuel injection systems are better for the environment because they reduce harmful exhaust emissions, helping automakers adhere to environmental requirements and promoting a cleaner environment. The technology is essential for achieving strict emissions rules by precisely controlling the air-fuel combination. This accuracy allows for the best air-fuel ratios, which optimize combustion and, as a result, increase power output and fuel economy.

Because a fuel injection system can more precisely control the air-to-fuel ratio, it results in a more efficient use of fuel, reduced fuel consumption, and lower emissions. The electronic system can constantly tweak the balance depending on the engine’s needs, resulting in less wasted energy and better fuel efficiency. Because it is more efficient, you get complete combustion, so fuel is burned in a cleaner way, leading to fewer pollutants.

Fuel injection systems occur in various forms, including electronic fuel injection (EFI), which has emerged as the norm. EFI uses different sensors to monitor engine characteristics and modify the fuel supply as necessary. By permitting the employment of catalytic converters and exhaust gas recirculation systems, this real-time adaptation improves performance and helps cut emissions.

Engines with fuel injector replacements frequently display a faster throttle response, smoother acceleration, and higher power output than their carbureted counterparts. This is crucial for modern cars because they must strike a balance between strength, effectiveness, and environmental responsibility.

Frequently asked questions