S40, T4, Bj 97 turbopipes..?

Hello community bought me a T4, year 97, as a butcher, I drove 420 km, which runs really well : ) but always starting from about 3000 tours starts the loader , I suppose, to whistles . That then becomes higher, if the speed rises, is that normal , did not have that with my C70 2.0t , can someone tell me something about it ? Thanks for the help already