There is a Video on YouTube showing an awesome sound simulation for engines: I don't know how BeamNG generates its sounds at the moment, but that may be something for BeamNG.drive to improve its sounds.
Yeah, it was just uploaded a couple days ago... I was actually coming here to post the same thing as I have been working on a similar simulation for a long time, but his is far better than mine currently... mine doesn't make sound.
It was posted earlier here : https://www.beamng.com/threads/engine-simulator-by-ange-yaghi.87487/ Anyways, it looks dauntingly awesome