RE: Trying to get more speed with my warbird
While I have not run an ASP engine, to the best of my knowledge is it not an OS knockoff? I beleive it is and that would suggest low compression. That being true it would benifit from the higher nitro provided that it be run with the correct heat range plug and not be loaded down with too big a prop. Doing so would just lead to pre-ignition. As I stated before you must shift the power band to a slightly higher RPM. Raising the exahust timing will do this and provide a better RPM match for the Jett Muffler. Lowering the load with a smaller dia. prop with a little more pitch will also help bring the engine into the RPM range that the Jett muffler is tuned to. Remember that ignition timings is determined by 3 things. Compression, nitro content and plug heat range. You will have to do some experimentation along with prop size to get maximum performance. In my case as I race with a Rossi .61 FIRE engine with a pipe. With head shimming, the correct pipe length, correct heat range plug I am able to spin an APC 10X10 in the low 17,000 range with 15% nitro. Makes a 6.5 LB airplane really haul.