I had various mics placed and recorded the full process of putting the keys in the ignition, cranking and putting into gear and then idle. This was in a nissan frontier.
Turning on a car and let it idle for a moment, this was done outside so there is also some wind blowing which i think is nice but that can be removed if so desired. Recorded with my zoom h2n.
An old hard drive starting up. The idle sound is from the hard drive itself and not the computer's fan noise. Some minor editing has been done to remove a slight bass rumble from the computer's fan. Recorded on sony pcm-a10.