Whats the difference between the s4 na/turbo and s5 na/turbo afms?

 

S4's used an aluminium flap AFM; S5's used a plastic sliding cone AFM. Both styles work in exactly the same manner and there's no advantage to using one over the other. NA and Turbo AFM's are calibrated differently to suit the respective engines' different airflows. You should always use the correct AFM for your model.

 

thanks, just what i needed to know.