Originally Posted by BatFink
Why is it a external wastegate produces noise yet an internal ones doesn't?
Because its exactly that, external, meaning it vents to atmos rather than being part of the standard exhaust system. they have there own smaller exhaust pipe that vents either straight down or side exit or any other configuration etc.
Originally Posted by Rs1
Would an external be heard if the dump pipe was fed back into the system rather than vented to atmo??
No, cause the noise you here is it venting to atmos, if you pipe it back into the exhaust it will be like a normal internal gated turbo only without the restriciton, I think martoons and Porkies 3dr are like this due to them doing a lot of trackdays