Mk6 GTI Underboost Error

[Herschel]

I have a Mk6 GTI on which i replaced the turbo & redone the cylinder head over the weekend.
The car feels slugish & has a P0299 underboost error. The error only reappears when flooring the car after it has been cleared.

Could the turbo's actuator be set incorrectly from the factory or do i need a DV spacer,since the car has stage 2 Stealth software on it?

[Crazy_Touran]

i think your most likely issue is the stock diverter valve. check if its seating correctly and check if the diaphragm isnt torn. if all is good id look at resetting the actuator and then if the issue still persists, check the n75 valve.

[Herschel]

i think your most likely issue is the stock diverter valve. check if its seating correctly and check if the diaphragm isnt torn. if all is good id look at resetting the actuator and then if the issue still persists, check the n75 valve.

The entire turbo was replaced over the weekend,so the diverter & N75 valve are new.
I had this issue previously with the old turbo also,but it went away on it's own.
That's why i was wondering if i should get the GFB DV+ spacer,due to the higher boost required by the software.

[panic-mechanic]

need to log a bundle of stuff to see. But unless it request crazy boost you should not need a different DV. could be an actuator issue or lots of other potential places you can lose boost.

[Herschel]

need to log a bundle of stuff to see. But unless it request crazy boost you should not need a different DV. could be an actuator issue or lots of other potential places you can lose boost.

All pipes have been checked for leaks. Non found.
With the stage 2 tune, the ecu requests 1.2 bar boost, compared to the stock tune that only requires 0.8 bar.
Thats why I'm leaning towards maybe needing a DV spacer.

[Trishen94]

The dv spacer will cause even more boost loss