Enter the engine speed in RPM and the speed of sound in the intake to calculate the optimal length of the velocity stack.
Velocity Stack Length Formula
The following formula is used to calculate the optimal length of a velocity stack:
LS = (C / 4) / N
Variables:
- LS is the length of the velocity stack (mm)
- C is the speed of sound in the intake manifold (m/s)
- N is the engine speed (revolutions per minute)
To calculate the velocity stack length, divide the speed of sound in the intake manifold by four times the engine speed. The result gives the optimal length in millimeters to help maximize the engine’s air intake efficiency.
What is a Velocity Stack?
A velocity stack, also known as an air horn, is a trumpet-shaped device that is part of the air intake system of an internal combustion engine. It is designed to allow smooth airflow into the intake manifold and can improve the engine’s performance by optimizing the air pressure waves within the intake system.
How to Calculate Velocity Stack Length?
The following steps outline how to calculate the Velocity Stack Length:
- First, determine the engine speed (N) in revolutions per minute (RPM).
- Next, determine the speed of sound in the intake manifold (C) in meters per second (m/s).
- Next, gather the formula from above = LS = (C / 4) / N.
- Finally, calculate the Velocity Stack Length (LS) in millimeters.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Engine Speed (N) = 6000 RPM
Speed of Sound in Intake (C) = 343 m/s