Everytime I accelerate, around 2nd or 3rd gear, I hear this whistling noise everytime i step foot on the pedal. I have a 2001 Honda Prelude Automatic. I heard it could be a timing belt, alternator, water hose, or the vacuum hole or something like that..

 

CAI could make a similar sound like a whistle

I dont know how knowledgable you are with your car, i dont mean to insult you if i did

 

but its more like a suction sound i guess tho

 

I get the same thing, thought it involved the window being rolled down

 

x2 for the air intake, i have f22b jdm dohc, same thing... i had a (i think it was weapon r) on my last lude with h23 and then kept it for my h22, it didn't whistle.. this is an AEM CAI and *almost* mistakenly sounds turbo...

My guess is #1, intake or #2, could be an exhaust leak ... it could be a belt done up too tight as well, just need to know your car as mentioned above.