Yesterday, I turned the radio off and discovered a new sound that E30 makes.
First, there is this spooling up sound around at 1800-2200 RPM. Yesterday I discovered E30 also makes Pshhhhhh sound when I step off the gas pedal (partucularly loud when like going 50kmh in 4th gear, then stepping on the gas pedal for a second and stepping off - pshhhhhhh) and when I change gear.

A bit like a blow-off valve there.

I don't know why I did not hear before. Now it is cold outside (-1 degrees Celcius), maybe the temperature has something to do with the sound....
Anybody heard that sound? (I have manual, of course!)