I just finished replacing the head on my brothers R56 (08) and it runs good but I don’t think it’s making boost.The second gens are new to me so don’t know what to expect but I don’t hear any turbo noise and would think it would have more power. Car is bone stock. I pulled the diverted valve off and applied 12v and it opened. I applied vacuum to the solenoid under the intake and did not hold vacuum on either port. Please help.

 

check the vacuum lines going to the little canister under the intake manifold. they tend to swell and slip out.

 

How many miles on car and turbo?
Was it boosting before the head work?

If high miles (>80K) on turbo, it's possible turbo wastgate is bad. They seem to give out around 80K miles.

Good luck

 

Also check the lines under the car to make sure they're secure (not sure what they're called boost/vacuum) if the car was making boost before you did the work.