Have fun sticking, clipping the modular sound generators to the inside of the car.
A whistle via tube clipped to open window or air vent moderated by sprung opening,
A glopping made from water in a pendulum, with spring swing adjustment and sound amplifying opening.
from of a small drum with adjustable skin tension and a choice of various bouncing weights.
A clash from a small cymbal hit by release of a spring which has a period due to ratcheting.
A wheeze from a reed instrument powered by weighted bellows.
Just ask mum or dad to speed up or slow down. Sometimes breaks will need to be used.