I am posting here because I am sure that there is a lot more experience with this turbo on this forum
I put a is38 turbo on my wife's TT MK3 roadster and it has been fine for a few weeks until yesterday when it threw an overboost code. I was not in the car, so I am not sure what lights went off, but it went into limp mode and the engine light came on. I am not sure if the EPC light came on. It threw code P0234
I am running a Unitronic 2+ tune and a Unitronic stage 2 DSG tune. The recommend that the actuator rod be adjusted to between 3.5-3.9 volts on the upper and .8-.9 volts on the lower. I currently have the actuator rod at 3.843v and .843v. Maybe I need to lower the voltage a little bit?
Other mods are:
Modded OEM Intake
034 high flow filter
I also changed the plugs to NGK 06K905601M and gapped them to .024 and changed the coils.