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Why Convert Carburetor to Fuel Injected Engine

Engine Problems with Kia Sportage

Mechanics convert carburetor to fuel injected engines for easy starting, better power and fuel consumption, not to mention cleaner emissions. Most weber-equipped vehicles in the 1960s and 1970s were performance vehicles. Petrol was cheap, and owners weren't concerned with MPG figures. Even emissions were terrible, and engine life was limited. However, things have changed, and we now have the ability to solve all of the consumption and emission issues by installing fuel injection.

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In this article, we will learn more about the carburetor and fuel injection, its respective benefits and disadvantages, and to make sense of why many choose to convert carburetor to fuel injected engines. 


Convert Carburetor to Fuel Injected: What is a Carburetor?


Gasoline engines are designed to take in just the right amount of air to ensure that the fuel burns properly, whether the engine is cold or running hot at top speed. A carburetor, also known as a carburettor, is that device that mixes air and gasoline for internal combustion engines to achieve the proper air–fuel ratio for combustion. 


You might think “carburetor” is a strange word, but it is derived from the verb “carburet.” This is a chemical term that refers to the process of enriching a gas by combining it with carbon or hydrocarbons. In other words, a carburetor is a device that saturates air (gas) with fuel (the hydrocarbon).


Carburetors, which are no longer found in new cars, have provided fuel to the engines of every vehicle, from legendary race cars to top-of-the-line luxury vehicles. They were used in NASCAR until 2012, and many classic car enthusiasts still drive carbureted vehicles on a daily basis. With so many die-hard fans, carburetors must offer something unique to car enthusiasts.


How does a carburetor work?


To draw air and fuel into the cylinders, a carburetor uses the vacuum created by the engine. Because of its simplicity, this system has been in use for a long time. The throttle can be opened and closed, allowing more or less air into the engine. This air flows through a narrow opening known as a venturi. This produces the vacuum necessary to keep the engine running.


Imagine a river flowing normally. This river flows at a steady rate and has a consistent depth along its entire length. If this river has a narrow section, the water will have to move faster in order for the same volume to pass through at the same depth. When the river returns to its original width after the bottleneck, the water will try to maintain the same velocity. This causes the higher-velocity water on the far side of the bottleneck to pull on the lower-velocity water approaching the bottleneck, resulting in a vacuum.


The venturi creates enough of a vacuum inside a carburetor for the air passing through it to consistently draw gas from the jet. The jet, which is located inside the venturi, is an opening through which fuel from the float chamber can mix with air before entering the cylinders.


The float chamber acts as a reservoir for a small amount of fuel, allowing it to flow easily to the jet as needed. As the throttle is opened, more air is drawn into the engine, bringing more fuel with it, causing the engine to produce more power.


The main problem with this design is that the throttle must be open for the engine to receive fuel. At idle, the throttle is closed, so an idle jet allows a small amount of fuel to enter the cylinders to prevent the engine from stalling. Excess fuel vapor escaping the float chamber is another minor issue (s).


The advantages carburetor has is its simple design so it’s also easy to service. With that a local mechanic can easily fix its problems. Not to mention that the spares you might need are affordable.


A carburetor feeding system's frequent response against revving and over raving is a very common feature and advantage. As a result, it is ideal for off-road and dirt bikes. Fuel contamination can be overlooked in carbureted engines, despite the fact that it degrades performance. Fuel feeding system that is ideal for low-cost, low-capacity motorcycle engines.


When it comes to disadvantages, the fact that it cannot provide a consistently perfect air-fuel ratio and cannot control the waste of fuel effectively. More of its spare parts are also in some complex designs making faulty parts diagnosis difficult. 


Engine cold start is a major issue in the carburetor fuel feeding system. In a carbureted engine, a lean/rich mixture is frequently a source of frustration. In carbureted engines, emissions are significantly higher due to inefficient combustion. In some cases, the engine vibrates, and spark plug fouling is a common problem.


Some carburetor designs also suffer from vapour lock, which causes engine stalling. It also has lower mileage and power than fuel-injected systems. Engineers later developed ‘Fuel-Injection' systems to address the shortcomings of the carburettor. For those carburetor engined cars mechanics offer to convert carburetor to fuel injected.


Convert Carburetor to Fuel Injected: The Fuel Injection System


Herbert Akroyd Stuart invented the first fuel injection system. He used a Jerk Pump at the end to pressurize the fuel. Bosch and Cummins later commercialized his invention in diesel engines. Fuel injection has always been used in diesel engines by design, and by the mid-1920s, it was standard on all diesel vehicles. However, it was the Hasselman engine, invented by Jonas Hasselman in 1925, that saw the first use of modern fuel injection in a gasoline engine.


Fuel injection is the use of an injector to introduce fuel into an internal combustion engine, most commonly a car engine. All Diesel engines use fuel injection, and many Otto engines use some form of fuel injection.


The main disadvantage of a carburetor is that a single carburetor supplying a four-cylinder engine cannot provide the exact same fuel/air mixture to each cylinder because some cylinders are further away from the carburetor than others.


Fitting twin-carburettors is one solution, but they are difficult to tune properly. Instead, many cars are now equipped with fuel-injected engines or mechanics convert carburetor to fuel injected engines that deliver fuel in precise bursts. Engines with this feature are typically more efficient and powerful than carbureted engines, and they can also be more economical and emit fewer harmful emissions.


The fuel-injected engine has an electronically controlled fuel feeding system, as well as an electronic fuel injection system. Fuel is fed into the combustion chamber via electronically controlled injectors. Here, too, air is sucked through the intake manifold, but fuel is sprayed or injected separately via a dedicated device.


It was only sprayed on the manifold or, in some cases, directly into the combustion chamber. As a result, the amount of fuel and the timing of injection are controlled digitally by an electronic device known as an Electronic Control Unit, or ECU. The ECU is linked to sensors that measure engine temperature, oxygen level, air intake or throttle butterfly position, and so on.


The ECU receives the measurements from the sensors and determines the amount of fuel to spray. As a result, the fuel injection system is a high-tech and complex fuel-feeding system. This modern technology and device significantly improved the capability and efficiency of modern motorcycle engines.


Many manufacturers used mechanical fuel injection on their high-performance sports cars and saloons in the 1960s and 1970s. The Lucas PI system, which is a timed system, was fitted to many British cars, including the Triumph TR6 PI and 2500 PI.


A high-pressure electric fuel pump mounted near the fuel tank pushes fuel up to a fuel accumulator at a pressure of 100 psi. This is essentially a short-term reservoir that maintains constant fuel supply pressure while also smoothing out fuel pulses from the pump.


The fuel flows from the accumulator through a paper element filter and into the fuel-metering control unit, also known as the fuel distributor. This unit is powered by the camshaft and, as the name implies, its job is to distribute fuel to each cylinder at the correct time and in the correct amounts.


A flap valve located in the engine's air intake controls the amount of fuel injected. The flap is located beneath the control unit and rises and falls in response to airflow – as you open the throttle, the'suck' from the cylinders increases airflow and causes the flap to rise. This modifies the position of a shuttle valve within the metering control unit, allowing more fuel to be squirted into the cylinder.


The fuel is delivered to each injector in turn from the metering unit. The fuel then squirts out of the cylinder head's inlet port. Each injector has a spring-loaded valve that is held shut by the spring pressure. When the fuel is squirted in, the valve opens.


When it comes to benefits, fuel injected engines take into account the environment and riding conditions, and it automatically balances the air-fuel mixture. Given the riding conditions, unlike the carburetor engine, it requires no fine-tuning. Engine vibration is reduced, and the issue of spark plug fouling is minimized. There is no need for manual choking in a fuel-injected engine because there is no cold start issue.


In terms of drawbacks, the fuel injection system is a complex electronic-controlled device that is linked to a few electronic sensors and a complex engine control unit. Its maintenance or repair scope is extremely limited, and it is not possible in regular service centers.


In addition, the entire system is quite pricey. In some cases, due to limited repair or maintenance options, the entire setup must be replaced. A good quality and recommended quality of fuel is required in fuel-injected engines. Contaminated fuel can even cause the engine to stop while driving.


Convert Carburetor to Fuel Injected: Carburetor Vs Fuel Injection




A fuel injection system with electronically controlled fuel induction can constantly adjust the fuel delivery to the cylinders, resulting in improved performance. A carburetor is incapable of determining the proper air-fuel ratio and struggles with changing air pressure and fuel temperature.




By the 1990s, the carburettor had been phased out of the automotive industry, with fuel injection taking its place and gaining prominence. The carburetor had a number of drawbacks. For starters, a carburetor cannot be used in diesel vehicles. Fuel injection, on the other hand, is available in both electronic and mechanical forms for both diesel and gasoline vehicles.


Cost and Complexity


The only parameters in which a carburetor outperforms fuel injection are cost and complexity. Carburetors are relatively easy to clean and rebuild. Repairing a fuel injection system presupposes professional assistance or even an expensive replacement.


Carburetors, as purely mechanical devices, outperform fuel injection in terms of cost and complexity. You can rebuild a carburetor on your porch or at a rest stop with a can of carburetor cleaner, simple hand tools, and possibly a couple of spare parts.


Whereas with fuel injection, even with years of training and experience, as well as a few thousand dollars in diagnostics equipment, you will still require a tow truck to get you off the road if your system fails. Most small engines, such as those found on motorcycles, lawn mowers, and snowblowers, still use carburetors because they are not emissions-regulated, are inexpensive, and are simple to operate.


Fuel Economy


A fuel injection system precisely delivers the right amount of fuel and can be tweaked based on several parameters, resulting in less fuel waste and improved fuel efficiency. A carburetor is incapable of adjusting the fuel ratio based on engine conditions.


In summary, mechanics or car owners who do diy projects to convert carburetor to fuel injected engines to improve fuel efficiency and performance. There are two kinds of fuel injection. The type most commonly found on newer vehicles today has a single injector for each cylinder. This is a type of multi-port fuel injection that necessitates the installation of a new intake manifold as well as fuel rails. But it is the throttle body injection system that is less difficult to install.


Convert Carburetor to Fuel Injected: Other Frequently Asked Questions


Does EFI add horsepower?


EFI can actually increase horsepower in many applications (although some would argue that a big carburetor always makes more power). A larger throttle body works well with EFI at all engine speeds.


Which gives more mileage carburetor or fuel injection?


In the city and on the highway, the carb variant returned 48.54kmpl and 55.02kmpl, respectively. Aside from that, fuel injection vehicles emit far fewer carbon-based emissions than carbureted vehicles.


While the carburetor has been around for over a century, fuel injection is clearly superior, providing more power, better fuel economy, and lower emissions. This is all that a modern driver could want so many choose to convert carburetor to fuel injected engines, it being a better method of introducing fuel into the cylinder.

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