When I go fast, I use to hear the engine rev louder, and I hardly hear the turbo spooling or whistle. But now, me and my buddy, who has a Volkswagen 2001 Jetta 1.8 turbo ( Wolfsburg Edition ), we were having fun... racing on the street that is. When I passed him, and then we came to a stop light. He then came next to me and made a comment that my turbo whistles very loud, and never noticed it before.