efficient expansion chamber silencing

[Deleted member 12676]

If you have ever listened to an expansion chamber unsilenced you would swear that they were designed to increase the exhaust noise as much as possible, and you wouldn't be far from the truth. The area of the stinger is usually around 60% of that of the header so the exhaust pulse is compressed as it goes through the stinger. Its exit thereof is like a mini explosion as the compressed gas rapidly expands into the air. But even with the same stinger size you can let the chamber gases exit from the side of the belly for an incredible noise reduction because the exit is 90 degrees perpendicular to the rearward direction of exhaust gas pulse. That side exit alleviates the pressure in the chamber and so the "pulses" exiting there are not so pronounced.
I just tested my exhaust system after relocating the stinger from the rear of the baffle cone to the side of the belly. That, in conjunction with my new design of silencer, results in less noise exiting the silencer than what I can hear from the cylinder. (I need to insert fin vibration dampeners.) This is as good as it gets for a high performance engine.
I am in the process of making free construction plans for the silencer as I don't believe anyone would pay $60 for a silencer (which would be the price from my distributor).
This design is an offshoot of the Russian silencer I have been bragging about. It works even better than mine but the inventor is waiting for a factory to buy his design.

 

[Fabian]

Can you post photos of everything - why not make a video as well!

 

[Deleted member 12676]

Here is a picture of it on my bike.

 

[Fabian]

How does the muffler or silencer work - what are the physical specifications of the baffle geometry inside the rectangular box?

 

[Deleted member 12676]

Here is a side view of the internal paths in the silencer. The shortest path snakes about a bit and as it is doing that it is allowed to expand into other chambers. With the belly stinger and this silencer I don't even feel sharp exhaust pulses coming out of the silencer. Relocating the stinger is actually easier than making the silencer and will give excellent results no matter what silencer you use. But the two together are super excellent. I don't know how long before I can have construction plans ready. Tomorrow I am doing testing of exhaust gas temperatures in relation to exhaust port heights of 2 different cylinders to see how much of a relation there is. All for use with my Excel file for designing an expansion chamber. Otherwise the designer has to buy a $100 meter and drill a small hole in the header to measure the exhaust gas temperature. Then I have to figure a way to incorporate the 3rd generation baffle return wave into the 1st generation to give a realistic view of the final return wave that will affect engine performance. Excel file programming is quite cumbersome but is resulting in nice graphics that let you see the strength and shape of the waves returning to the cylinder.
(This graphic of the silencer should say its length is 12cm, not 12mm.)

 

[Fabian]

Excellent work Jaguar - i want to see more of your innovative experimentation

 

[Deleted member 12676]

OK the plans are mostly finished and can be found on my site at http://www.dragonfly75.com/motorbike/silencerplans.html

 

[Fabian]

Can you please attach photos of the internal components of your silencer on your website.
Although the information presented is good, it's a bit confusing when looking at the plans.

 

[Deleted member 12676]

I will if I make another. Right now the only one I have is on my bike and it's sealed at the edges with JBWeld and is painted and so I don't want to take it apart to take pictures.

 

[Fabian]

I think that we all look forward to you making another silencer and taking photos of the internal components, but the best option would be to make these silencers available for purchase, either through your website or through the JN Motors website.

I really want one of your silencers!