These are a great addition for All Motor and Turbo applications. Blox offers 3" and 4" in aluminum and also composite. A velocity stack is a cylindrical tube with a radiused inlet end device which is added onto the air entry location or locations of an engines intake system. It can be attached to an airbox inlet or to each cylinder in an IR (individual runner). Used with or without an "airbox". It is designed to:

1. Allow smooth and even entry of air into the intake duct with the flow streams boundary layer adhering to the pipe walls.

2. Modify the dynamic tuning range of the intake tract by functioning as a small reverse megaphone which can extend the duration of pulses within the tract.

3. Alter the dynamic tuning speed (dynamic engine compression) if the overall length is changed thereby changing the tuned length to a lower or higher rpm.