How to know/calculate the pitch of a sound?

I been recording engine sounds to put these in a game (Street Legal Racing Redline). The sounds are from differents RPM’s ranks and are constants. To put in the game i have to write in a code differents values for each sound (initial volume,final volume,rpm rank, etc), one of these values is the pitch of the sound, is a 4 digits number. How can i know/calculate these pitch number?

Let’s call “x” the number I want to know: if i put bigger number than “x”, the sound hears slowly and grave, otherwise, if i put a smaller number than “x”, the sound hears faster and sharp. So i want to hear the sound in-game just like from the media player.

There is a pitch detection plug-in available for Audacity here: http://wiki.audacityteam.org/wiki/Nyquist_Analyze_Plug-ins#Pitch_Detect
However, it probably will not work for “engine sounds” because engine sounds are essentially “noise” rather than a distinct “pitch”.

You can also look at the frequency content of a sound using the “Plot Spectrum” tool: http://manual.audacityteam.org/man/plot_spectrum.html

To change the pitch of a sound, Audacity has these tools available:
http://manual.audacityteam.org/man/change_speed.html
http://manual.audacityteam.org/man/change_pitch.html
http://manual.audacityteam.org/man/sliding_time_scale_pitch_shift.html
http://manual.audacityteam.org/man/time_tracks.html