I think about how many times things like this happen to individuals that don’t have the weight to warrant an article where their entire collection of online data just gets wiped out and Google responds with: ¯\_(ツ)_/¯
Don’t trust your data to the cloud, folks.
Most older games will have 2-3 engine loops that they will blend between and pitch accordingly, however Forza 5 specifically was the first in the series to use granular synthesis which is a much more modern approach.
These will have a series of sound files including all the different parts of the engine, exhaust, turbo, etc. Then the software slices these files into tons of pieces in real-time and plays the slices based on the players inputs.
It’s tricky to explain without examples, so here’s a video that does a decent job of explaining how it works in music: https://youtu.be/ftDLRYnRYZQ?si=SEHOl55K7rimi4Eu