I was running 2 "slicked up" Zenoah twins to test carb..The prop was a 16-12 wood..The fuel was 20% nitro..The exhaust is 7 inches long, to comply with the rules..Tested 4 different carbs..WJ64 modified for methanol, a $400.00 EC Birt Tillotson, a


Walbro SDC 80,and a Herbrandson twin drone carb, modified and bored out to 23 MM..
They ran within 1 or 200 rpm of each other..Then I took a stock 445 to test with the 4 carbs..Almost the same result..Makes me wonder why we take the time to modify the stockers..
We'll test the engines in the race plane, with a race prop, later..The reason for the 11,000 rpm is to test the carbs at the rpm the engine turns in the air..
The instructions that come with the 445 recommend props that will turn bertween 7 and 10,000 in the air, so there's no wonder the engine seems meek at 5 or 6,000..Like running a car at 20 mph in 3rd gear..The instruction also say the max power is at 10,000 rpm--Who reads instructions ??
If you want power at 5,000 rpm, get a 3W or DA that was designed to run at that speed....
The modified engines might unload better with the race prop...