ORIGINAL: Flyboy Dave
....they might work (give a boost) to a four stroke engine.
I was thinking the same thing. But, I don't run 4-strokes and I am not spending +/- $200 on a super charger and another $200 on a 4-stroke just to find out. I'll let someone else do the research.
Agreed on the 2-stroke application-- it'll never work. Waste of $$$$$.
Best thing you can do for a 2-stroke is put a tuned pipe on it. But, with smaller engines, it tends to make them peaky. They run great when "on the pipe" and they run doggy when they are not on the pipe. Makes for a very narrow powerband. Hard to control. Great if you want to race or go fast. Flick the throttle wide open and watch it go like nuts. Horrible if you want to 3D where the throttle is being juggled up and down constantly.
Totally different on a larger gasoline engine. Most gas engines will respond VERY well to a tuned pipe. They give great performance over a very wide powerband without any of the "peakiness" usually associated with small glow engines.
Of course, these are generalizations. It's possible to put a tuned pipe on a small glow engine and get smooth power over a large range. But, you will not get that MAX HP that most people associate with tuned pipes. You CAN get more power than a stock muffler if you tune it right. Tune it for torque by cutting the header to the right length. That gives a mild improvement in HP and offers smooth transition over a very broad powerband. You can't tune for maximum HP and expect it to transition worth a darn. You can make a small 2-stroke go like nuts with a tuned pipe, if you cut the header short for max HP. But it won't idle or transition well enough to satisfy the needs of most sport flyers.