What is what does a velocity stack do?

A velocity stack is an engine component that is designed to improve the air intake efficiency, increase airflow into the engine, and enhance the engine's fuel combustion process. It is usually a trumpet-shaped device that is attached to the intake manifold or carburetor of an engine.

Velocity stacks work by allowing the air to flow smoothly into the engine with as little turbulence as possible. They create a low-pressure area at the entrance, which helps to suck in more air. This results in an increase in the amount of air that enters the engine, leading to better performance and improved throttle response.

Moreover, the shape and length of the velocity stack can be tuned to target specific RPM ranges, which can enhance the engine's performance at particular speeds. Therefore, velocity stacks are commonly used in high-performance racing engines, especially in motorsports such as Formula 1, as they can provide instant throttle response and improved acceleration.