yes, mine would spike to about 17 psi, even removing my boost controller it would go to 14 psi. as soon as i got the injectors and power fc fitted, i could tune it down to 11 psi no problems, i got a highflow turbo as well. i may be wrong but you have all the same problems i had, i even changed my split dump to a bellmouth but nothing changed, everyone was saying ,check the actuator, check for leaks, but in the end it was the tune, a rich tune will cause extra gasses in the exhaust spooling up your turbo beyond what your wastegate can handle. once it is leaned out and ignition sorted it should go away
my saga
http://www.skylinesaustralia.com/forums/Ov...ml&hl=boost