Unfortunately, we can’t tell you how best to model a jet engine in your game, because we don’t know what your game’s requirements are, and because we’re not experts on jet engine behaviour. For expert information about jet engines, we recommend consulting academic journals on the topic (https://en.wikipedia.org/wiki/List_of_academic_databases_and_search_engines), or directly consulting with pilots, aeronautical engineers or other experts in the field.
We should mention that FMOD Designer’s built-in engine designer tool is just one possible way to model engine behaviour. Many sound designers prefer to adopt different models that to better represent the engines they’re trying to recreate, or that are a better fit for the way their game simulates engine behaviour.