How do I simulate a restrictor on an EFI engine with a plenum and individual runner throttle plates?
The best way is to pretend the vehicle is using a single plenum EFI Type manifold with appropriate length runners, a plenum matching your air box, and then a restrictor ahead of that To calculate the Carb/Throttle Body CFM rating, click on the Clc button for Carb/Throttle Body CFM Rating. Then just use the dimensions of the restrictor. (The restriction of the other throttle plates in the runners is negligible compared to the restrictor.) For a “perfectly designed” venturi type of restrictor, the “% Improved” spec in the Clc menu should be about 150%.
