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What is difference between a top mount and side draft carburettor


Top mount and side draft carburetors are two different configurations of carburetors used in internal combustion engines. They have distinct characteristics and advantages, and the choice between them depends on various factors, including engine design and application. Here are the key differences between top mount and side draft carburetors:

1. Mounting Orientation:

  • Top Mount Carburetor: As the name suggests, a top mount carburetor is mounted on top of the engine's intake manifold, with the air and fuel mixture entering the engine from above. This configuration is commonly found in older engines and some off-road vehicles.

  • Side Draft Carburetor: A side draft carburetor is mounted on the side of the engine's intake manifold, with the air and fuel mixture entering the engine horizontally. This configuration is often used in high-performance and racing applications.

2. Air/Fuel Flow:

  • Top Mount Carburetor: In a top mount carburetor, the air and fuel mixture flow downward into the engine's intake ports. This design can be more susceptible to fuel distribution issues, especially in multi-cylinder engines, because gravity may not distribute the mixture evenly to all cylinders.

  • Side Draft Carburetor: Side draft carburetors provide a more direct and horizontal flow of air and fuel into the intake ports. This design is often preferred for its improved cylinder-to-cylinder fuel distribution and potential for better performance.

3. Performance and Tuning:

  • Top Mount Carburetor: Top mount carburetors are typically associated with older, less performance-oriented engines. They may be less efficient at delivering precise air/fuel ratios, limiting their suitability for high-performance applications.

  • Side Draft Carburetor: Side draft carburetors are commonly used in high-performance and racing engines due to their superior airflow characteristics and tuning capabilities. They allow for easier fine-tuning to optimize engine performance.

4. Space Requirements:

  • Top Mount Carburetor: Top mount carburetors may require more vertical space in the engine bay, limiting their use in some vehicle designs with low hood clearance.

  • Side Draft Carburetor: Side draft carburetors are often preferred in applications with limited vertical space because they have a more compact profile.

5. Aesthetics:

  • Top Mount Carburetor: Some classic car enthusiasts appreciate the vintage look of top mount carburetors, making them a popular choice for restoring older vehicles.

  • Side Draft Carburetor: Side draft carburetors are often seen as a more modern and sporty option, which can complement the aesthetics of certain performance or racing vehicles.



In summary, the choice between a top mount and side draft carburetor depends on factors such as engine design, performance requirements, and space constraints.


While top mount carburetors have historical significance and may be suitable for certain applications, side draft carburetors are favored in high-performance and racing contexts due to their superior airflow characteristics and tuning capabilities.

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