James,

I am using your setup exactly in my Alliance including the 16X12 APC

My engine has only just returned from a holiday in Japan where they fixed it under warranty after the second cam failure. This setup produced 8700 -8800 rpm with restrictor in place.

The model is certainly very lively with this power plant. The DZ engine is not a high revving engine. What I am trying to say is smaller props wont necessary yield higher RPM. There is a point were RPM remain the same. I found the 16 x 12 to be a good setup. The 16.5 x 12 W works very well in calm conditions on a model which weighs under 4.6-7 Kg.

If your getting only 8.1K on this prop you do have a problem. If it has done a bit of work try replacing the ring.

My setup is

1 3/4 turn on the high
Approx 1 turn in from flush on pump
16 X 12 APC
restrictor
Coolpower 30% LV
OSF
Hatori header with 698 pipe

peter