I have started this thread to split this issue out of my med9 tuning thread. I hope someone can help. I am having very inconsistent boost and I am not sure where to start looking. following is a wot throttle run in 3rd gear with the n75 in place but not connected to the wiring loom, from this it looks like my wastegate is working 100% and only cracking at 1.4bar and the boost stays linear. (stock file)



I then reconnected the n75 and this was the result. huge boost spike and then boost very lumpy.



I then set CWMDAPP = 8 set all cells in KFLDRAPP = 0 to try and start doing a pid calibration and my boost is all over the place, I am missing something surely the n75 should act the same at 0% duty cycle as it would if it was electrically unplugged? instead I am getting these results.

yup n75 changed, same result.

this from another forum

"I test myself and have found that with n75 unplugged the throttle plate closed. Set Cwmdapp to 1 and set KFLRAPP to 0%"

both n75s were plumbed the same way on both turbos, if it was plumbed wrong surely it wouldnt have worked when disconnected electrically?

pretty sure its routed correctly. bottom hose to compressor housing, middle hose to wastegate, top hose to turbo intake

bit
CWMDAPP
7 6 5 4 3 2 1 0
+---------------+
|x x x x x x x x|
+---------------+
ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ
| | | | | | | +--B_zwappl
| | | | | | +----B_fpwdkap
| | | | | +------B_wdksap
| | | | +--------*)
| | | +----------B_ldsafw
| | +------------B_plsolap
| +--------------
+----------------

B_zwappl = Zundwinkelapplikation torque condition without intervention
B_fpwdkap = DK control directly via the accelerator pedal
B_wdksap = DK control over fixed value, bit 1 has priority
B_ldsafw = LDR runs on control with fixed value LDRAPP
B_plsolap = Changeover: target boost pressure setpoint boost pressure on application

so am I not meant to have CWMDAPP set to 5? B_ldsafw = LDR runs on control with fixed value LDRAPP

*) B_ldsapp = B_zwappl or B_fpwdkap or B_wdksap or CWMDAPP.Bit3

then where to from here, how do you suggest I sort this issue out................

so with the help of Rarak, i decided to do what I wanted to do initially and that was to copy across the PID maps from the ed30 GTI which is K04 in stock form and this has smoothed out the boost considerably. I forgot to enable turbo mode in vcds so the resolution isnt so high but you can see the difference. I will do more logging this evening to verify thats its better but the car feels smoother.