ORIGINAL: speed lover
Im thinking of making an exhaust and wanted to make a megaphone shape like a tumpet straight off the port and wanted to try and use the theory of the velocity stack basicly have the speed of sound travel from the port back to the port as the port opens back up but am having trouble getting this worked out sounds crazy I know. But when flying my trainer a couple of years ago with an os la the nut fell off with vibration and the end came off the exhaust during flyte but I thought it sounded pretty grizzly just above tick over and would love to experiment as I hate that screaming noise and those quiet pipes you can barely hear any help on how to maximize the noise and get the calculations for the velocity stack design also was at an airshow and was looking at a spitfire and the exhaust pipes were tiny is there a short distance exhaust pipe tunning formula
speed lover,
2 stroke exhaust is a spooky, black art of a design problem. Formulas can get you in the ballpark, but then you must test if you want to really get there. Does an unmuffled tuned pipe not get the noise where you like it? Anyway, there are no magic formulas for what you are trying for. There are chapters in text books and entire text books written on this subject....Some reading is required if you really plan on understanding what you are doing and getting results that aren't just a function of guesswork. Some books to look at:
2 Stroke Performance Tuning by A. Graham Bell
Design and Simulation of Two Stroke Engines by Gordon P. Blair
The 2 Stroke Tuner's Handbook by Gordon Jennings
Also look at MOTA simulation software, it is pretty reasonably priced and does a decent job on small 2 strokes, glow and gas.
Mark