well i took the s4 out for a spin today and as it spools past maybe 8-10 psi it makes a crazy weird hissing sound....i shift into 2nd punch it at about 2000 rpm it starts to spool normally then when i hit maybe 2800-3200 rpm it makes a loud hissing noise and i feel like i just loose it. anyone else have this trouble? i want figure out where thie leak is coming from. my dad thinks its coming from the diverter valve but its such a loud hissing noise.

thanks guys