[color=#000000]Ok;
Finally got my test rig going and setup a 150 inch monometer, I ran four tests on each orifice size as follows.
1. Single motor full speed.
2. Two motors in parallel (standard build configuration)
3. Two motors in series one feeding the other
4. Four motors two feeding two.
What I learned was that as Tony predicted the performance gains of a two stage system are minimal but you get twice as much noise . I put the data in a combined sheet using Larry