Variable Length Intake Manifold (VLIM)

Variable Length Intake Manifold (VLIM):

An automobile engine manifold technology, which can vary the length of the intake tract to optimize power and torque as well as to improve fuel efficiency. Also called VRIS (Variable Resonance Induction System).

It has two main effects:

1. Swirl, which helps form a homogeneous air-fuel mixture which ignites without detonation. At low engine speeds, air is directed through a longer path with limited capacity, increasing the speed of an flow. At higher loads, shorter and higher capacity path opens to increase the amount of air flow.

2. Pressurization by means of a tuned intake path which has a high pressurizing effect similar to a low-pressure super charger, due to Helmholtz resonance. This effect occurs only over a narrow engine speed band, increasing engine output.