Forced Induction

Forced Induction: Explained

Forced induction systems are essential for enhancing vehicle performance by compressing air and delivering it to the engine’s combustion chamber. This process increases the density of the air available for combustion, significantly boosting engine output beyond the limitations of natural atmospheric pressure. The primary types of forced induction systems are turbochargers and superchargers, each offering distinct benefits and operational dynamics.

Understanding Turbochargers

Turbochargers are a popular choice for forced induction systems due to their high efficiency. They harness the energy of the exhaust gases to spool a turbine, which in turn drives a compressor to force more air into the combustion chamber. This process doesn’t require engine power, making turbochargers more efficient than superchargers. However, one downside to turbochargers is the phenomenon known as boost lag, which is the delay in response time from when you hit the accelerator to when the turbocharger delivers the power.

To mitigate this, some vehicles use twin sequential turbochargers. This system uses a smaller turbocharger for lower RPMs and a larger one for higher RPMs, effectively reducing the spool time and improving the vehicle’s performance across a wider RPM range. Another important concept is the boost threshold, which is the RPM range where the turbocharger operates most efficiently. Operating outside this band can lead to decreased performance and efficiency.

Exploring Superchargers

Superchargers, on the other hand, are driven directly by the engine’s crankshaft, usually via a belt or chain. This direct connection allows superchargers to deliver boost even at low RPMs, eliminating the issue of boost lag. The boost threshold for superchargers is generally superior to that of turbochargers, meaning they can operate efficiently across a wider RPM band. However, because they draw power directly from the engine, superchargers can put more strain on the engine and decrease overall fuel efficiency.

Upgrading Your Forced Induction System

Whether you choose a turbocharger or a supercharger, upgrading your forced induction system can significantly enhance your vehicle’s performance. However, it’s important to remember that these upgrades should be paired with improvements to your cooling system. As forced induction increases the amount of air entering the combustion chamber, it also increases the heat generated. An upgraded cooling system will help manage this heat, ensuring your engine operates efficiently and prolongs its lifespan.

Choosing the Right Forced Induction System

Choosing between a turbocharger and a supercharger depends on your specific needs and preferences. If you’re looking for high efficiency and power, and don’t mind a bit of boost lag, a turbocharger might be the right choice for you. If you prefer immediate power delivery and a wider boost threshold, a supercharger could be a better fit. Regardless of your choice, both systems will provide a noticeable increase in power and performance.

At Compare.Parts, we offer a wide range of forced induction systems and related parts to suit all types of vehicles and performance needs. Explore our selection and find the perfect upgrade for your ride today.

Frequently Asked Questions about Forced Induction

Is it worth fitting a performance air filter?

Fitting a performance air filter can offer several benefits:

Improved Airflow: Performance air filters are designed to increase airflow to the engine, which can enhance performance.
Better Engine Efficiency: With improved airflow, the engine can operate more efficiently, potentially leading to better fuel economy.
Enhanced Throttle Response: Many users report a more responsive throttle, which can improve driving experience.
Longer Lifespan: Performance filters are often reusable and can last longer than standard filters, reducing replacement costs over time.
Potential Power Gains: Some drivers experience a slight increase in horsepower, although this can vary based on the vehicle and filter type.

However, the actual benefits can depend on the specific vehicle and driving conditions.

What are the cons of camming your car?

Camming your car can enhance performance, but it also comes with several drawbacks:

Increased Engine Wear: A camshaft can put additional stress on engine components, leading to faster wear and potential failure.
Reduced Fuel Efficiency: Performance cams often result in lower fuel economy due to altered air-fuel mixtures.
Compromised Driveability: Cams can affect low-end torque, making the car less responsive at lower RPMs.
Noise Levels: Performance cams can increase engine noise, which may not be desirable for all drivers.
Potential Emissions Issues: Altered engine performance can lead to higher emissions, potentially causing issues with regulations.
Cost of Installation: Upgrading to a performance camshaft can be expensive, including parts and labour.
Compatibility Issues: Not all engines are compatible with aftermarket cams, which can limit options.

Do camshafts change engine sound?

Yes, camshafts can change the engine sound. The design and specifications of a camshaft influence the timing and duration of valve openings, which affects the engine's performance and acoustics. Factors that contribute to changes in engine sound include:

Lift and Duration: Higher lift and longer duration can create a more aggressive sound.
Profile: Different camshaft profiles can alter the exhaust note.
Engine RPM: Camshafts designed for higher RPMs may produce a different sound compared to those for lower RPMs.
Engine Type: The overall engine configuration (e.g., V8, inline) also affects how camshaft changes impact sound.

Why do cammed cars sound choppy?

Cammed cars sound choppy primarily due to the characteristics of the camshaft profile. Here are the main reasons:

Lift and Duration: A camshaft with higher lift and longer duration allows more air and fuel into the engine, creating a more aggressive sound.
Overlap: Increased overlap between the intake and exhaust valves can lead to a rougher idle, contributing to the choppy sound.
Idle Speed: Cams designed for performance often require a higher idle speed, which can accentuate the choppy noise.
Exhaust Note: The changes in exhaust flow dynamics due to the cam profile can alter the exhaust note, making it sound more aggressive and choppy.

Does camshaft affect acceleration?

Yes, the camshaft does affect acceleration. The camshaft controls the timing and duration of the engine's valve openings, which directly influences engine performance. Key factors include:

Valve Timing: Proper timing allows for optimal air-fuel mixture intake and exhaust gas expulsion, enhancing engine efficiency.
Lift and Duration: Higher lift and longer duration can improve power output at higher RPMs, which can lead to better acceleration.
Engine Tuning: A camshaft designed for performance can shift the power band, affecting how quickly the engine accelerates.

In summary, the design and specifications of the camshaft play a crucial role in determining how effectively an engine can accelerate.

Does camming a car make it louder?

Camming a car typically involves installing a performance camshaft, which can indeed make the engine louder. This increase in noise is due to several factors:

Increased Airflow: A performance camshaft allows for greater airflow into and out of the engine, which can enhance the exhaust note.
Higher RPMs: Cams designed for performance often operate at higher RPMs, producing a more aggressive sound.
Exhaust System Interaction: The camshaft can change the way exhaust gases exit the engine, potentially amplifying the sound through the exhaust system.

Overall, while camming a car can lead to a louder engine sound, the extent of the increase will depend on the specific camshaft used and the overall setup of the vehicle.

How much does it cost to replace a camshaft?

The cost to replace a camshaft can vary significantly based on several factors, including the make and model of the vehicle, labour costs, and whether you choose an original equipment manufacturer (OEM) part or an aftermarket part. Typical costs include:

Parts: £200 to £1,000
Labour: £300 to £800

Overall, the total cost for camshaft replacement can range from approximately £500 to £1,800. Always consult with a mechanic for a precise estimate based on your specific vehicle.

Do camshafts increase horsepower?

Yes, camshafts can increase horsepower. They play a crucial role in controlling the timing and duration of the engine's intake and exhaust valves. Upgrading to a performance camshaft can enhance airflow, improve engine efficiency, and increase power output. Benefits of a performance camshaft include:

Improved airflow into and out of the engine
Increased torque and horsepower at higher RPMs
Better throttle response
Optimised engine performance for specific driving conditions

However, the extent of the horsepower increase depends on various factors, including the engine type, other modifications, and tuning.

What does a higher lift camshaft do?

A higher lift camshaft increases the amount of valve lift, allowing the engine to draw in more air and fuel during the intake stroke. This can lead to improved engine performance in several ways:

Increased Airflow: More air entering the combustion chamber can enhance combustion efficiency.
Higher Power Output: With better airflow, the engine can produce more power, especially at higher RPMs.
Improved Torque: A higher lift can also contribute to increased torque, particularly in performance applications.
Enhanced Throttle Response: The engine may respond more quickly to throttle inputs due to improved airflow dynamics.

However, it is important to consider that a higher lift camshaft may require additional modifications to the engine, such as upgraded valve springs and potentially changes to the engine's tuning.

What makes a cam aggressive?

An aggressive camshaft is characterised by several key features that enhance engine performance. These include:

Increased Lift: Higher lift allows the engine to draw in more air and fuel, improving combustion efficiency.
Longer Duration: A longer duration keeps the intake and exhaust valves open for a greater portion of the engine cycle, allowing for better airflow.
Steeper Ramp Rates: Faster opening and closing of the valves can lead to more power at higher RPMs.
Overlap: Increased overlap between the intake and exhaust valves can enhance performance by improving scavenging of exhaust gases.
Profile Shape: The specific shape of the cam lobes can influence how the engine responds at different RPMs, with aggressive profiles typically favouring high RPM performance.

These characteristics contribute to a camshaft that provides more power and responsiveness, particularly in performance-oriented applications.