"The best way I've ever been able to describe a car is think of it as a really complicated wind instrument. The engine is sucking air in, it's causing an explosion, and it's sucking air out. That creates a note that resonates through the pipe much as you would with a brass instrument. By adjusting the length and the diameter of the pipe, you change the note of the car."
That's Turn 10 creative audio director Nick Wiswell on how the studio goes about recreating the vehicles in Forza Horizon, in the latest behind-the-scenes documentary from Kill Screen. Sure, these documentaries are kinda promotional, but they're also thoughtful and interesting, and worth a watch.
I have actually never thought of cars that way, and I basically think everything is a wind instrument.