I'm not sure if this is general, tech(probably not) or maybe modding?

Anyways, I'm wondering if it is possible to change details about a faction, let's say a custom faction, inside a save game, and have them translate into the game. 

I've tried this with a save, and edited a few things, and the game loaded alright, yet I did not notice any difference in game, so I assume I was unsuccessful - or the descriptions stayed the same, of course. 

I did not yet try re-saving it to see if the changes stay, or are immediately discarded. I edited the game.bin and gamesavedescriptor.bin (where does one even read that description?).

Is there a list of what I would be searching for?