Just checking something.

I just got a decat downpipe put on my 94 WRX, and I heard this whistling thinking it was the Bailey DV, but then I was told by the garage when I got it checked out, that it's the turbo spooling up.

But even if you rev it on the spot you can hear a whistle, does the turbo spin when you rev it?

 

A turbo charger is exhaust gas driven...

 

It will spin, but you wont get any boost to speak of, unless you sit with it bouncing of the rev limiter, not a good idea

 

yes you will hear the turbo whisle it is normal as you press throttle it will whisle more but will die out to the noise don't worry they sound great if you change the up pipe to it gets louder...

 

great isnt it. Cruise along at about 2.5k revs and gently easy your foot down, you will quite clearly hear the turbo spooling up, then at around 3k you should be close to full boost (with a TD04) and it's go go gadget wheels.