Turbo or actuator?

[dalespencer]

Hi guys. A friend of mine went for mapping last week at h-Dev, he has nismo 740cc injectors, gt2872r, z32 maf and all the other supporting mods. On the rollers it only made 326bhp. Jez said that when he tried turning the boost up it just shot up way to high and that it seems like something is restricting the exhaust flow. We used the actuator off the t28. I was wondering if that Was the. Cause or if it's a fault with the turbo? It has a japspeed manifold and it made 327 with the last set up so we know it's not that. Thanks in advance.