ORIGINAL: rowdyjoe
Thanks for the tip Dave. I have tired heli fuel in my other two Saitos (bot FA-80's) and it does seem to help. However, I have a Turbo-Header on one and it gives me about 300 rpm more running 20% or 30% so, I've stayed with 20% for those two engines. I don't have that muffler for the .91 so heli fuel may do the trick. I'll fy it on the 20% (because I have it on hand) and see how she performs. If she needs it, I'll pick up a Turbo-Header for it AND run 30%.
RJ
With the APC 14x8 the engine needs more torque to pull the larger more efficient prop.....not more RPM. The 20% fuel is not enough for that prop.
The 30% fuel will probably do the job....instead of losing RPM on an upline this fuel will maintain the RPM and the flight performance will increase substantially.
Try this combo first and see how you like it and then the header if you think it is needed.
Better adjust the valves while you are at it and use an OS F plug.