Open Waste gate “Flutter”
 

is There anyway for me to prevent this? I notice some cars make the noise and others don’t, is there any reason behind it?

https://youtu.be/UjqBI-cjqsw

WHat are you using for a boost controller? Also, what size wastegate? The wastegate may be too big from my research. I came to know this as wastegate surge in my WRX.

I using a three port electronic boost solenoid plugged into the EVAP connection controlled through Ecutek.

The waste gate is a Tial 38mm open dump

There's a setting in Ecutek for wastegate frequency. A higher frequency will modulate the wastegate faster so it sounds like BWAAAAA while a lower frequency will modulate the wastegate slower so it sounds like BWA-BWA-BWA-BWA. Hope that makes sense!

There's a section in the Ecutek tuning help PDF for this platform that has more information on it in the Boost Control section. The suggested frequency in there is between 20 and 30, which corresponds to a BWAAAAA sound.