[ninjanoob]

Hello all, I am trying to design some mufflers for my bike. I have access to a machine shop as well as someone who has the experience to machine the parts with me.

My question to you all is what dimensions would you suggest for the diameter and length?

Below is a crude mockup of the overall design I am going for.

I had to use Google Sketch as I dont have access to AutoCAD or anything proper so the looks are basic.

Also I am wondering what the diameter of the baffle should be as well as how close the baffle should be to the end of the muffler.

The other thing that I have to take into account is that my bike is currently a dual exhaust setup. Will that change the length of the pipe? I somehow think that it would.

I am trying to achieve the proper resonance without ending up creating ungodly amounts of back pressure.

Go easy on me I haven't designed anything in quite a long time.

Thank you

 

[spooph]

Area = pi x Diameter (radius x radius)

Make your baffle twice the area as your headers coming out of the block, or the same size your midpipe coming into the can, and you should be reasonably good. There is very little effective difference here. If you really want to "tune" the pipe for sound, I think I can dig up some sound frequency equations. This is relevant by the way, because sound is air, and if you tune for a specific sound, and match it with your RPM's, you can get a reasonable correlation, although not neccesisarily an imperical, scientificcally perfect system. The sound frequencies would give you the length of the pipe, since you already figured out the diameter. Ask if you have more questions. Good luck.

 

[virtualmatrix258]

Spooph why you're not a bike designer or engineer is beyond me.

 

[ninjanoob]

Thank you spooph for the information. I have decided to go with 4 inch stainless. I have already cut the materials and am waiting until later this week or next to weld it up. I will post pics and video if it turns out.

cheers

 

[Crispy]

If it turns out well, you could make a lot and sell them...

 

[spooph]

Virt, because I want to keep enjoying it, and besides, most engineers that I know that ride are pansies... Maybe I don't know the right engineers?