Variable Intake Plenum Tuning Basics

Variable intake plenums are popular enough in todays crop of engines, but what exactly are they and what does that mean for out tuning?

In this quick example we're looking at an older 3UZFE variable intake plenum (aka variable-length intake manifold (VLIM),variable intake manifold (VIM), or variable intake system (VIS)) and an older MoTeC tuning file for some basic insight into how this system works, why it exists in the first place, and of course a few key points to remember when tuning if you have the required functionality.

------------------------------------
TIME STAMPS:
0:00 - Variable Inlet Runners
0:27 - Longer Vs Shorter Inlet Runners
0:45 - 3UZFE Example
2:30 - Tuning Aspects/Considerations
4:40 - Switch Over Hysteresis
5:20 - Break Points/Resolution
6:01 - Thumbs Up, Free Lessons
------------------------------------

 Want to learn how to EFI an aftermarket ECU like a MoTeC, Haltech, Link, AEM, Syvecs, EMtrom, Maxx, Ecumaster, MegaSquirt, Arduino, MicroSquirt, Holley, FuelTech, ME or something else completely different? Start with some free lessons right here: https://hpcdmy.co/EFI101y