Nitro engines don't just blow out smoke! Have you ever removed the muffler and see the power drop? Most think the power loss is lack of fuel pressher. Even so. That is not the main cause of the loss in power this can be proven by using a airplane fuel pump to compensate and if you went threw all this trouble you would find that it still is down on power and just makes alot of noise! For a two cycle engine to have max output it has to have a certain amount of back pressher. Many hours go into designing mufflers with the major gole being power not noise reduction. The most important part of the muffler is the reducing wall infront of the outlet pipe. It literally sends a fairley big portion of unburnt fuel back into the engine. However you are right as far as the 2 cycle engines being one of if not the worst engines when it comes to efficiency!!!
