The stock n55 TMAP is only good for reading up to 2.5bar (36.25 psi), which is the sum of both the barometric pressure reading (typically 14.1 to 15.1psi) and the pressure built up in the charge-pipe (stock 8psi to 21psi+). It is easy to see how the stock sensor is not ideal when pushing the limits of the stock turbo.
The answer is to move to a 3.5 bar (N20) TMAP or even a 4bar sensor. The problem is the stock plug fits into the N20 sensor upside down. You can either buy an adapter, or, you can re-pin your stock plug which is what I chose to do.
Sensor:
https://www.ecstuning.com/b-genuine-...r/13627843531/
The process is simple really:
1) Use something flat (screwdriver) to release the latch on the plug that holds the pins in place.
2) Use something like a paperclip or a thumbtack to release the pins.
3) Pull pins out of the plug.
4) Reinstall pins in reverse order.
5) Plug in your new N20 TMAP sensor.
6) Flash your new tune that is re-scaled to take advantage of an N20 TMAP (MHD for N55 has this option).