engine vibration

[nicku]

Hi guys..
so I upgraded my turbo from t25 to s15 t28 last night
everything was great except when I accelerating during 3000 to 4500 rpm, the engine is vibrating. I am not quite sure it was engine vibrating or exhaust vibrating because the whole floor and everything is vibrating together. Pass 4500 rpm or before 3000 rpm it is just fine. nothing wrong at all. What would be the problem that I am facing of?
And also between that range, I can feel the power has flat spot during that range, and after 4500 the power comes back again.

[nicku]

anyone?? any opinion would be helpful

[kamikazekid]

could have loose dump pipe bolts/ exhaust bolts. flat spot could be a turbo leak? just double check your gaskets and fasteners, these type of problems end up being somthing simple.:)