I have an '05 STi with ~27000 miles that I just acquired. When the throttle is applied, there is a loud buzzing-like sound. It stops immediately as the thottle plate closes. The car has a BOV and cold-air intake. The sound is much louder than the turbo (drowning out the whistling of the turbo), and is particularly evident above 40mph. Any idea what this may be? It's not a normal occurance with a cold-air intake is it? Thanks.

 

could be the turbo going....does it sound almost like a loud whistle/buzz?

my turbo was just blown, sounded like a loud buzz/whistle/rattle. almost like the car had asthma. stopped when I let off the throttle, occured whenever turbo was spooling/i gave it throttle

 

Well I don't think it's the turbo. I can hear a seperate "whistling" of the turbo when it's spooling (the typical turbo sound). But the buzzing/rattling starts immediately when you go on throttle and stays the same intensity regardless of rpm. Could it possibly be the gearbox?

 

a problem like this needs to be looked at not just described on the web.

 

possibly the BOV, which one do you have and have you set the firmness of it?

Also, who installed it, possible boost leak from not tightening down one of the nuts?