Wilkinson removed the internal restriction. I think it was a 1-3/4" internal ring. I also think that was a sound reduction device on the original Ansa design.
When you increase the id of it, you increase the sound level emitted. There is some type of a graph on that somewhere?
Think of it this way, the additional sound is the 50 additional horses trying to get out.
I feel a sound level comparison coming on now in this thread? Anyone else feeling those vibes?