Julex I did some testing with my new turbo which spools a lot lot quicker than the previous one.
I still have zero part throttle surging issues at lower than wastegate pressure.
I can hold 10 or 15psi part throttle without any issue.
Just an fyi bud.
It is probably my set up specific. I see that I am getting turbo stutter (surging) when I go light-medium part throttle and car gets too excited with throttle and allows boost up to say 15psi and then rapidly cuts off throttle to bring boost down so that load matches limit.
At this point of time, say at 5psi, the turbos start stuttering/surging in waves, cha, cha, cha, cha in sometimes run-away fashion (amplifying with each cycle). I see in logs exactly what is happening...
PRJ's insight into the throttle regulation FUEREG will allow me to properly tune this problem by making car aware that wastegates cracking pressure is much higher than it thinks it is.
I don't have problems if I request hefty amount of load to begin with, like gas pedal deep in so that I reach 15psi for example. No surging then.
I just want a car super smooth in all load points with no on-off switch 95% of 2.7t tuned engines provide...