Hi.

Here is some pictures of my new muffler for our MB engine if someone is interested.
Hopefully it's even quieter and just a little less powerfull as the previous one.
Total weight is 40g, 1,4oz.
Construction is about the same as previous one (only stronger) with 2 expansion chambers and a side resonant chamber in the middle. Just with slightly more flow resistance and more laminar flow. L

Very nice workmanship.

 Well, I should have said less turbulent, or more predictable. I did that by off-centering the central tube, now it's not directly on the way of flow coming from exhaust header. The old muffler had some issues at very certain rpm's and I hope this will make the operation a bit more stabile.
 The old muffler, as calculated by Rob, is very quiet. But it is tuned to be "neutral", it does not have much effect to the engine power. It works very well in certain conditions (the hotter the better) but the engine becomes unstable in colder weather. That's because our engine is so light, big and powerfull. It is difficult to keep the operating temperature high enough, and the best way to deal with it is to increase exhaust pressure. I would like to load the engine more but bigger than the current 14x6 3-b is too much for my model.
 Also, I have new cylinders coming with new porting and some ideas for combustion chamber shape to make burning more stable. I try to finish those before the summer comes.
 I find it strange that so few people are working to make engines quieter, especially when the world is getting more and more sensitive to noise. Most of the silencers used are quite stupid and noisy.  For a very quiet end result, it is not necessary to loose lots of power in a highly reactive silencer (like with Retro's), not every engine likes that way. L