You know, that is a GREAT question!
I first heard it in mom's '74 Super Beetle and have always just accepted
that "it's a VW thing", and never put much more thought into it than that.

You can always tell a VW (ok, OLDER VW) by its sound before anything else.

Something I've always wondered about...what creates that signature VW
> "chirp" coming from the engine?
>