so recently I just installed a new stock turbo and I was driving today and I was getting on it and my peak boost only seemed to hit around 15 psi it seemed to flounder a lot on the boost gauge needle. Before I did the install I was around 19 and the boost gauge floundered but not as much. It is obviously slower and doesn't seem to pull at all now. I need help fast thank you in advance.

 

hmm did you check for boost leaks

 

This same scenario is currently happening with my wife's FXT. Well, no boost gauge installed but it is definitely not as quick. I initially suspected a boost leak but the system is tight, and there are basically two components in a Subaru turbo system that were removed (turbo and TMIC)

I question if the wastegate arm is adjusted the same as the stock arm was? That might be the problem in the FXT but I haven't jumped on it yet because I'm making sure the vehicle runs correctly before tackling the issue.

Maybe check your wastegate actuator and see if it's adjusted the same as on your old turbo?

 

where in chicago are you? we can take a look sat morning.

 

Stock boost controller? If so check and make sure you didn't reverse the boost lines.

 

How would I be able to tell if they are reversed is there any way to tell and on the new turbo I got a 10.5 hot side which I'm pretty sure is bigger then the old one but I'm not sire why that would drop boost pressure

 

The MHI wastegate actuator is adjustable. You need to increase WG spring pressure. This operation can be accompplished with the turbo on the car and is pretty straight forward and simpple.

 

Taifighter, was it a used turbo? If so, I would try swapping the wastegate actuator from the old turbo to the new one. There are different springs in different year TDO4 actuators.

OP, if you try adjusting the arm, I would do it only 1 turn at a time. tighten it just enough to reach your target boost. If it's too tight, the turbo will be probe to boost spikes.

 

Double post fail

 

The new turbo I put on was a stock evo 8 from the dealership