Alfa 159, Brera & 946 Spider
Is the amount of air measured approx. linear to RPM when engine just free-reving.
Ex. if 350 at idle, then at constant 1900 RPN, the amount should be 700 & 1400 at 3800. (Offcourse still without any load on engine)
It a 2.4 210..But should be pretty same for any engine i´d guess :-)