I have 88 Saab 900 turbo (purchased 3 days ago) and i thought the turbo and boost gauge hasn't been working. I went out this morning and noticed that when i'm in 3rd gear when i give it gas and bring th rpms to about 3500+ the needle in the boost gauge starts moving up and i hear a "whistling" sound. is this normal? is that my turbo kicking in only past 3rd gear. I tried 2nd and went to 4400 rpm and nothing but loudness..