Boost Performance: 4 Hole Vs Open Carb Spacer Comparison

Published by Dustin Babich on

A 4 hole carb spacer provides better low-end torque and throttle response, while an open carb spacer increases high-end horsepower. Carburetor spacers play a vital role in optimizing engine performance.

A carb spacer is a thick plate installed between the intake manifold and carburetor to enhance airflow and improve efficiency. Carb spacers are available in various materials, shapes, and sizes. In this article, we’ll be discussing the difference between a 4 hole carb spacer and open carb spacer.

Feature4-Hole Carb SpacerOpen Carb Spacer
DesignContains four holes arranged in a specific patternDoes not have any holes or restrictions
AirflowProvides a more controlled and directed airflowAllows unrestricted airflow
Fuel AtomizationEnhances fuel atomization by promoting turbulenceMay not have as significant an impact on fuel atomization
Low-end TorqueImproves low-end torque by increasing air velocityMay have a lesser impact on low-end torque
Mid-range PowerProvides good mid-range power due to improved mixture formationMay not have as pronounced an effect on mid-range power
Top-end PowerMay have a slight reduction in top-end power compared to an open spacerMay provide better top-end power due to unrestricted airflow
Fuel EconomyCan potentially improve fuel economy due to better mixture formationMay not have a significant effect on fuel economy
Engine ResponseEnhances throttle response and drivabilityMay not have as noticeable an impact on engine response
Intake NoiseMay reduce intake noise due to the controlled airflowMay increase intake noise due to unrestricted airflow
ApplicationOften used in street and mild performance applicationsCommonly used in high-performance and racing applications

These two types of spacers are the most popular among engine enthusiasts and racers. We’ll examine their features, advantages, and disadvantages to help you make an informed decision when choosing the best carb spacer for your engine.

Carburetor Spacer Basics

Carburetor spacers play a vital role in enhancing engine performance by facilitating the smooth flow of air and fuel mixture. They are interposed between the carburetor and the intake manifold and come in different types based on their use, such as open or 4-hole.

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Open spacers are meant to maximize plenum volume while 4-hole spacers offer better throttle response and more stable air-fuel mixture. Carburetor spacers come in various materials, including aluminum, plastic, or wood. Each material has its unique properties influencing factors such as strength, heat resistance, and price.

A well-designed carburetor spacer can significantly contribute to increased horsepower, improved fuel economy, and smoother acceleration. To maximize benefits, it’s essential to consider the engine’s specific requirements when selecting and installing the carburetor spacer.

Understanding 4 Hole Carb Spacers

Carb spacers are a widely used performance mod for racing and high-performance engines. 4 hole carb spacers feature four holes drilled into the spacer plate, which allow for increased airflow to the carburetor. This results in improved fuel atomization and a more efficient combustion process, which translates to increased horsepower and torque.

However, it’s important to note that 4 hole spacers can also cause a decrease in low-end torque due to the increased airflow. Despite this, the benefits of using a 4 hole spacer can outweigh the drawbacks for certain applications. For example, in drag racing, the increased horsepower at high rpms can greatly improve overall performance.

Careful consideration of the intended use and engine setup is necessary before deciding to use a 4 hole carb spacer.

Understanding Open Carb Spacers

Open carb spacers are an essential component for high-performance engines. These spacers help increase airflow volume and fuel charge velocity, leading to improved engine combustion. The primary benefit of using open carb spacers is that they increase horsepower and torque output.

However, excessive use of open carb spacers can lead to reduced low-end torque and throttle response. One real-world example of using an open carb spacer is in oval track racing, where it can significantly improve engine performance. Overall, understanding the use of open carb spacers and their advantages and disadvantages is crucial for optimizing engine performance in various applications.

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Comparing 4 Hole And Open Carb Spacers

Comparing 4 hole and open carb spacers head-to-head comparison of 4 hole and open carb spacers reveals interesting differences. Performance enhancements offered by each type have specific nuances. Generally, 4 hole spacers improve low-end torque and drivability. Conversely, open spacers provide power at high rpms.

As for usage scenarios, 4 hole spacers are useful in street-driven cars and trucks, whereas open spacers are perfect for racing applications that require maximum horsepower gains. Pros and cons of using either 4 hole or open carb spacers depend on the engine setup, fuel delivery, and compression ratios.

Selecting the appropriate carb spacer depends on the driving conditions, engine size and configuration, and other mechanical factors.

Frequently Asked Questions Of 4 Hole Vs Open Carb Spacer

What Is A Carb Spacer Used For?

A carb spacer is used to increase the distance between the carburetor and the intake manifold, which can improve the engine’s performance.

What Is A 4-Hole Carb Spacer?

A 4-hole carb spacer has four small holes that allow for better fuel atomization and distribution, resulting in improved performance and fuel efficiency.

What Is An Open Carb Spacer?

An open carb spacer does not have any holes and is used to isolate the carburetor from heat radiation, resulting in cooler air intake and improved performance.


To sum up, carb spacers are an essential component for any high-performance engine. Choosing between a 4-hole versus an open carb spacer ultimately depends on your desired outcome. While a 4-hole spacer has been the traditional choice for years, an open spacer offers improved high rpm performance.

With an open spacer, you have the added benefit of better airflow, which can translate to a noticeable increase in horsepower. However, in some cases, a 4-hole spacer may be the better choice if you’re looking for a more significant low-end torque.

Ultimately, the decision on what type of carb spacer to use will depend on your specific needs and expectations. Regardless of what you choose, be sure to pay attention to the details, such as thickness, material, and design, as they can also impact your engine’s performance.

With the right carb spacer, you can get the added boost you need to take your engine to the next level.

Dustin Babich
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Dustin Babich

Dustin Babich

As the passionate author behind, Dustin Babich is a knowledgeable expert in all things automotive. With a deep understanding of car tools, equipment, engines, and troubleshooting techniques, Dustin Babich shares invaluable insights, practical tips, and effective solutions to empower readers in overcoming car-related challenges.


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