Boost problems

[Aaon321]

Having a problem with my 1.9tdi mk5 golf golf. Put a new turbo on a few months back. Since then the car hasn't been boosting correctly, in first gear it goes like a sdi until 3000rpm then it makes a knockin noise. Then boosts 100%. Also it fills the road with smoke. It's isnt the egr valve, nor is the cat blocked. If done every test possible but still can't seem to find out what the problem is. Anyone got any ideas.