Yes, to a point the inner diameter of the signal line will make a difference in wastegate function. Will there there be a difference between 4mmID and 6mmID? Probably not.

When I switched to push-loc from rubber hose, there was no appreciable difference in function, and the push-loc has a substantially larger ID and smoother wall than what I was using.

If you think you need to redo your signal source, knock yourself out. You need a softer wastegate spring.

@Hugh no need to apologize my friend.I appreciate you are trying to help me.

And yes that little difference in the inner diameter worked.Made car's peak boost from 1.8 to 1.2.But i want to reduce it more,till 1 bar.

My spring is 1 bar so it has to work until 1 bar.I am thinking of vaccum leak.

Ok, test this. Take the line that goes in the bottom input of the wastegate and put it in your mouth. Go for a ride. When you hit the throttle blow hard. Can you hear the external ? Shoot a video while doing this and send it to us for commentary.

I am afraid i'll break the external,with my strong lungs!Thes kai video mlk....xaxa