Hello,

A 60 trim compressor wheel and basic 1600cc engine generally surge above about 18 psi. The correct compressor wheel for that spec engine on a 0.48 turbine is preferably a 50 trim if you want a BIG mid range boost spike without surge, or a 55 trim for a recommended held 22psi. The 60 trim compressor wheel is I'm affraid a very poor wheel in general.

The only other option is to use a different cam, but assuming everything else is correct, essentially you've got the wrong spec turbo!