Dynamically change pitch

Hello all,
I have an engine sound record where rpms keep changing (i.e. the driver accelerates); I would like to get the same pitch for the whole sound, for use in videogames; any tips?
Thanks in advance,

Chop out a tiny bit where the pitch is constant, and loop it, (seamlessly), using Audacity’s “Repeat” effect.
Then add some randomness to make it less obvious that it’s a loop.
“Random Amplitude Modulation” and “Random Pitch Modulation” plugins for Audacity here … http://audacityteam.org/download/nyquistplugins

Hi Trebor,
thank you for your reply; I’m sorry for my noobishness, but how do I loop it seamlessly?

Assuming that you have Audacity 1.3.12 (if not, you should update/upgrade http://audacityteam.org/download/ )

To loop a section of the file, the first step is to find a suitable section. Ideally you will be looking for a part where the sound is relatively constant for as long as possible. The beginning and the end of the loop should be as similar as possible. Looping is much easier with mono tracks, so if you have a stereo recording but a mono track would be OK, use “Tracks menu > Stereo to Mono”.
Note the “zero crossing points” at the start and end of the selection - this will help to avoid clicks when the section loops.

Test the loop by pressing Shift+Space (loop play).
When you have a selection that you are happy with, use “Repeat” from the “Effects” menu.

Experimenting with Audacity 1.3 “time track” or “sliding time scale/pitch shift” “Effect” could approximately correct changes in pitch.

[BTW “Dynamically change pitch” is what autotune software does ].