6674GTS

Hi, I just bought my GTS RB 25 Turbo model 1995 Automatic, My problem is that when the speed reach 180 Km and if I try to exceed 185 Km the engine refuse to drive faster!? some of my friends told me that there is a speed limiter fitted in the car but I dont know how to remove it?! one of my friends car can speed up to 250 Km and no speed limiter?!