The engine modifications affecting fuel economy | Your money depends on this.

Lets look at engine modifications affecting fuel economy in relation to the changes you make on different features and systems of the engine and their impact on fuel consumption.

Both small engines and larger ones are able to assimilate modifications that unlock the untapped potential of your car’s performance. For example, tuning air intake systems with induction kits, cold air intakes and high-flow air filters.

Furthermore, changes on the fuel system like cleaning fuel injectors, replacing them, and adjusting their flow rate also affects the car’s fuel economy. We will look into all these modifications without leaving out ignition systems, exhaust systems and ECU tuning.

Most people aren’t aware that there exists engine modifications that improve fuel economy. However, there are other ways that can reduce your car’s fuel consumption without performing any modifications.

The ever-increasing cost of fuel cannot be challenged nor lowered. Therefore, the alternative is to discover ways through which you can save on fuel costs and improve mileage.

Can you modify your car to get better gas mileage?

Gas mileage refers to a measurement of how far a vehicle can travel while using a specific amount of fuel. The measurement is either ”Liters per Kilometer” or ”Miles per Gallon”.

Achieving better gas mileage is both economical and environmental friendly. Therefore, car drivers have a curiosity towards the modifications that can help achieve a better gas mileage.

The aim of such modifications will be to positively impact your vehicle’s combustion and fuel utilization. However, their effect on gas mileage will depend on your car’s characteristics and driving conditions.

There is a need to consider how those modifications affect insurance cover, general vehicle drivability and emissions compliance.

Does ECU tune improve fuel economy?

ECU stands for engine control unit and its responsibility is to manage various engine functions. Tuning the ECU involves modifying the software or programming to optimize specific engine performance functions.

The goal is to maximize the engine’s power output and efficiency. Whereby, this modification affects fuel delivery, ignition timing, and the air to fuel ratio.

How does an ECU tune improve fuel economy?

Changes in the ECU software or programming for an improvement in fuel economy affect the engine’s fuel management and combustion efficiency. An ECU tune with a specific focus on fuel economy can lead to better gas mileage.

a]. Fuel management.

Changes on the engine’s fuel management will allow better fuel delivery to the combustion chamber. Precisely when the driver starts the engine.

The spot on fuel delivery during ignition prevents instances of engine misfire. Which also affects the car’s overall drivability because engine misfires are a leading reason why the car shakes.

Further, ECU tuning affects precise fuel delivery during acceleration. The driver hits the accelerator, which causes the throttle sensor to open the throttle valve hence allowing air into the engine’s cylinders.

This enables the necessary power output for acceleration.

b]. Combustion efficiency.

This is an ECU tune that focuses on the components of the combustion engine that directly affect the burning of the air/fuel mixture. Meaning that the tune will affect fuel delivery and ignition timing.

Secondly, the tune will affect the optimization of the air/fuel mixture. Ensuring there is a balance of the air to fuel ratio.

Air Intake Systems.

Cold Air Engine Intake

The air intake system supplies air to the engine cylinders for combustion. Therefore, it’s a crucial engine component that affects its fuel economy.

Further, the air intake system is an essential part of the engine cooling system and it affects engine performance. There are various components of the air intake system whose tuning affects the car’s fuel economy.

a]. Air filter.

The air filter is responsible for ensuring that the air which flows into the engine is clean. It removes any particles and other contaminants from the air.

Further, the air filter ensures smooth airflow from outside into the engine. Restrictions of airflow can occur when the air filter is dirty. Therefore, fuel mileage is negatively affected in such a case.

Installing aftermarket air filters will reduce the instances of clogging. Further, the design of such air filters allows for free airflow because they minimize any restrictions that you find in factory installed air filters.

b]. Cold air intakes.

The installation of aftermarket cold air intakes is in a position that optimizes their function of bringing in cooler air from outside the engine bay.

Hot air accumulates around the engine and this makes it hard for the engine to bring in cold air rich in oxygen. However, the cold air intakes enhance the airflow of cool air into the engine.

Cool air is rich in oxygen and therefore it’s much denser. Professionals install the cold air intakes in a position that optimizes their capacity to draw in the cool air.

c]. Throttle body.

The throttle body controls the amount of air entering the engine. It has a throttle valve which opens and closes at precise instances to allow air into the engine for combustion.

The throttle valve opens and closes when the driver accelerates and during slowing down. An upgrade to an aftermarket throttle body will involve the acquisition of a wider throttle body.

Hence leading to better airflow. Which in turn improves fuel efficiency.

d]. Intake manifold.

The intake manifold distributes the air and fuel mixture amongst the available engine cylinders. Intake manifold upgrades are inclusive of porting and polishing in order to improve airflow.

Additionally, porting and polishing enhance fuel combustion taking place in each engine cylinder. Hence, potentially increasing fuel efficiency. Alternatively, you may opt for the installation of an aftermarket intake manifold upgrade.

e]. Forced induction: Turbochargers vs. Superchargers.

Forced induction is the sucking of air into the combustion engine at a higher rate when accelerating. This produces more power when the engine is at high RPM.


Turbochargers utilize the energy from exhaust gases to compress the intake air. The turbocharger technology consist of a turbine that connects to a compressor through a common shaft.

When it is engaged, the exhaust gases pass through the turbine up to the turbine wheel. The turbine wheel spins and in turn this spins the compressor wheel.

Afterwards more air is forced into the engine which produces boost pressure. The boost pressure increases power output and it may lead to more fuel consumption.

Manufacturers that noted this came up with better turbochargers that reduce the rate of fuel consumption. They installed intercoolers in the turbochargers to lower the air temperature.

Cool air is much denser and has a lot of oxygen which improves fuel combustion. This therefore boosts fuel efficiency.

However turbochargers tend to have turbo lag. This is the delay in power delivery due to the time required for the turbine to spool up. Apart from turbo lag affecting power delivery, it also affects throttle response and overall drivability.


Superchargers are driven by an engine belt. They use compressors to increase the rate of taking in air into the combustion engine.

When compared to turbochargers, the superchargers are more effective at power delivery. Because they are driven directly by the engine’s crankshaft. Which eliminates the issue of turbo lag.

However, superchargers consume extra engine power to operate, which results in a reduction of fuel efficiency. Therefore, superchargers lead to more fuel consumption in comparison to turbochargers.

Does exhaust modification affect fuel consumption?

Yes, exhaust modifications have an effect on fuel consumption. The exhaust system is made up of different parts and their role is to help the engine breath. For example; exhaust pipes, catalytic convertors and mufflers.

All these parts of the exhaust system affect the car’s fuel consumption. Any exhaust system mods will impact your engine’s performance and therefore affect your vehicle’s fuel consumption.

However, before making such modifications, it’s essential to discover their impact on emissions. Additionally, ensure that they follow the legal requirements and they’re suitable for your car make and model.

a]. Aftermarket mufflers and resonators.

Mufflers reduce noise levels from the exit of exhaust fumes which the engine produces. However resonators manipulate the specific frequencies of exhaust noise.

Therefore, while installing racing modifications, most drivers install resonators mods to change the sound of the exhaust system. Hence making them louder like most modified Subaru WRX cars.

Aftermarket mufflers and resonators don’t have a direct impact on fuel consumption. However, such modifications can influence the exhaust flow.

Hence impacting engine performance efficiency. This therefore affects the vehicle’s fuel economy.

b]. Catalytic converters.

The exhaust system catalytic converter is responsible for eliminating the toxicity of exhaust fumes. They do so by removing the harmful pollutants that result from the burning of fuel within the combustion engine.

The stock catalytic converter can restrict exhaust flow and it can increase backpressure. This affects the engine’s performance negatively and that also has a negative effect on fuel consumption.

Furthermore, stock catalytic converters are prone to clogging and that’s why it’s essential to consult a professional for catalytic converter cleaning services.

Aftermarket exhaust system mods may include the installation of a catalytic converter. The aftermarket catalytic converter improves the removal of exhaust fumes pollutants.

Hence improving engine performance and this positively affects the car’s fuel economy. Additionally, it improves the flow of exhaust gases by eliminating the build up of back pressure.

c]. Exhaust headers or exhaust manifold.

Exhaust headers have long pipes that attach to each engine cylinder. The main goal of exhaust headers is to reduce exhaust pressure.

Exhaust headers are parts of the exhaust system that influence how the engine pushes exhaust gases out from the cylinders. This is a process that draws power from the engine.

Therefore, if there are any restrictions from the exhaust headers, the power draw for pushing out exhaust gases affects the engine performance.

Hence affecting the amount of fuel required by the engine to produce the extra power to push out exhaust fumes. Aftermarket exhaust headers replace the stock exhaust manifold to allow better exiting of the fumes.

Therefore, saving up on the extra power that goes into the process of eliminating exhaust fumes. This improves engine efficiency and saves on fuel economy.

d]. Cut back exhaust System.

Underneath view of car exhaust system

It is a performance exhaust system that’s installed to replace your OEM exhaust system. Installation is done backwards from the catalytic converters to influence the exhaust fumes back pressure.

Backpressure refers to resistance encountered by exhaust gases as they exit the engine cylinders. Engine efficiency relies on the capacity to remove any exhaust fumes that accumulate after combustion.

Some backpressure is necessary for basic engine performance. However the presence of excessive backpressure leads to a decrease in engine efficiency.

Further, it causes increased fuel consumption. Cutback exhaust pipes improve flow of exhaust fumes from the vehicle’s engine cylinders.

Because it has pipes that are larger in diameter when compared to the stock exhaust. Further, it has fewer bends along its length because it’s a straight-through exhaust systems which facilitate smoother flow.

e]. Exhaust wrap.

The exhaust wrap is one of the vehicle’s insulation material whose role is to maintain the high temperature of exhaust fumes. It does so by regulating the heat transfer from the exhaust system by keeping the exhaust fumes hotter.

This mod helps to maintain exhaust velocity and improve overall exhaust flow. Therefore, it has an effect on engine performance which improves fuel consumption.

Effects of the ignition system on fuel consumption.

The ignition system plays a vital role in engine efficiency and performance. There are different components of the ignition system. For example, spark plugs, ignition coils, ignition control modules and ignition wires among others.

a]. Spark plugs.

When you start the car, spark plugs ignite the air/fuel mixture in the combustion chamber in a combustion engine. They tend to deteriorate in quality over time because of the accumulation of soot from the combustion process.

However, there are different qualities of spark plugs whose lifespan varies from one to another. Additionally, aftermarket spark plugs improve the ignition process by allowing instant engine turn over.

This ensures efficient combustion, better fuel economy and engine performance. However, a faulty spark plug leads to loss of engine power and increased fuel consumption because of incomplete combustion.

i]. Ignition timing.

The ignition timing affects the rate of fuel consumption by your engine. Ignition timing refers to the precise moment when the spark plug fires in relation to the piston’s position.

Incorrect ignition timing leads to poor air/fuel mixture combustion, reduction in engine power, and an increase in fuel consumption.

Modern car engines have engine control systems that automatically adjust the ignition timing. This is on the bases of various parameters set by manufacturers with the intention to optimize fuel efficiency.

b]. Ignition coil.

The ignition coil receives electric voltage from the car battery and amplifies that voltage before transferring it to the spark plug. After the voltage reaches the spark plug, the fuel/air mixture in the combustion chamber burns to produce power.

A faulty ignition coil is one of the reasons why the car won’t start because it results to a weak electric voltage. This weak voltage results into a weak spark that interferes with the normal combustion process.

Therefore resulting to more fuel consumption. Proper functioning ignition coils can help to improve fuel efficiency because they provide a strong electric voltage that spark plugs use to ignite the fuel/air mixture in the combustion chamber.

c]. Distributor-less ignition systems and coil-on-plug systems.

This is a technology advancement in the ignition system that distributes the electric voltage from the battery directly to each spark plug.

These ignition system mods eliminate the energy losses that come with using distributors in the process of ignition. This is possible because they provide precise control of electric voltage.

This helps to improve the combustion process in a combustion engine. Therefore, it contributes to improving fuel economy because of the efficiency in burning the fuel/air mixture.

Performance suspension Kits.

Performance suspension system Modifications affecting fuel economy

The vehicles suspension system usually affects its weight. Further, proven studies have shown that a light vehicle usually uses less fuel.

The OEM suspension systems are not created to cater for light vehicle weight. It is possible  to replace the installed suspension parts with lighter streamlined components.

Doing so will ensure that the vehicle uses less power hence saving on fuel. Changing parts of the suspension system will include replacing sway bars, springs, struts and shocks. Ensure that the replacements are made specifically for performance enhancement.

Fuel Magnets.

Fuel Magnets modifications affecting fuel economy

As the fuel gets into the combustion chamber, it is usually pumped depending on how much power the car needs. In fact, this is affected by the terrain and the speed at which you are driving.

The fuel magnets break up fuel clusters getting into the combustion chamber. They regulate the amounts of fuel into combustible fragments.

So, this ensures that no excess fuel is released into the combustion chamber. Further, it ensures that each molecule of fuel is burnt sufficiently to give the vehicle power.

This is one of the most efficient engine modifications to improve fuel efficiency. In fact, by eliminating carbon and varnish deposits, you are able to save wear and tear on your engine. They are placed along the fuel line of your car.

Does engine affect fuel economy?

The engine affects fuel economy because of several components within the engine that influence how efficiently it uses fuel.

a]. Engine size.

Engine size can also be referred to as displacement. It’s a measurement of the cylinder volume swept by all of the pistons.

Engine size can affect the amount of fuel a car consumes as well as the amount of power the engine produces. Engine with a smaller CC size tend to have better fuel economy compared to those with a larger CC size.

Because the small engine cars require less fuel to produce power. Larger engines however, adapt engine modifications like direct injection and turbocharging which reduces their fuel consumption.

b]. Combustion engine design.

The engine design takes fuel delivery systems, compression ratios and the combustion process when determining fuel efficiency.

However much you may have a car that has a similar engine design with someone else, the way you drive it determines fuel efficiency.

Driving conditions work alongside technologies like variable valve timing, cylinder deactivation, and start-stop systems to determine fuel consumption.

c]. Type of fuel in use.

The type of fuel in use also affects fuel mileage. There are cars that run on gasoline, diesel, or alternative fuels like hybrid cars.

Each one of these engines use fuel at varying rates. Because each type of fuel has its own energy density and combustion properties.

d]. Transmission systems.

Car transmission maintenance improves fuel mileage by ensuring that power produced by the engine matches the gear as well as the spinning rate of the wheels.

Manual transmissions allow control over gear selection. Hence, enabling drivers to optimize engine rotation per minute [RPM] speed and fuel efficiency.

Alternatively, automatic transmission systems adjust gear ratios based on driving conditions. Thanks to the inclusion of advanced technologies like continuously variable transmissions (CVTs) and dual-clutch transmissions.

e]. Hybrid systems or electric powertrains.

These engine technologies have a significant effect on the car’s fuel mileage. Hybrid systems combine internal combustion engines with electric motors.

Therefore, they’re able to improve the car’s fuel economy by utilizing regenerative braking and electric power assist set-ups. The wheels receive power from both the electric motors and the combustion engine.

What modifications help fuel economy?

A vehicle’s fuel economy can improve after making a few changes to the car. Alternatively, changing your driving habits can also improve fuel mileage.

Driving habits include factors such as speeding, aggressive acceleration, high idling time, and thick traffic have an impact on fuel consumption.

There are some modifications that can help to improve gas mileage for your car.

a]. Aerodynamics.

There are some car body mods that reduce drag on a vehicle, making it to move more efficiently through the air. For example, aerodynamic body kits, adding rear spoilers, or modifying the vehicle’s shape.

b]. Car tires.

The car’s powertrain transfers power from the engine to the wheels in order to move the car. Using low rolling resistance tires reduces the energy required to move the vehicle, resulting in improved fuel efficiency.

c]. Weight reduction.

When you reduce the load the engine has to carry by making the car lighter, it minimizes the total energy being used to move. This saves on fuel and increases gas mileage. To achieve this remove unused accessories, or even choose lightweight materials.

d] Vehicle maintenance.

Vehicle maintenance includes attending regular car service as recommended by the professionals. This ensures that the car runs smoothly which in turn saves on fuel utilization.

Vehicle maintenance includes engine tuning, changing all filters, using the correct type of engine oil, and ensuring that the vehicle’s systems are in optimal condition.

What causes the car engine to consume more fuel?

Identifying the factors that cause the engine to consume more fuel is important in understanding how to improve gas mileage. Having looked at most of them before, we are going to just list them one by one below.

  • Poor driving habits.
  • Deterioration in the engine conditions because of bad maintenance of engine components.
  • Heavy vehicle weight.
  • Insufficient tire pressure.
  • Heavy traffic.
  • Poor fuel quality.
  • Mechanical issues with the vehicle’s systems.

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