2 stroke muffler

[xkevenx]

hi guys, i was thinking to make my own muffler for my suzuki, and dont worry i am a certified welder :cool: so my question is what is the best to do? a longer pipe or shorter, or a bigger hole or a smaller hole than the original? i was thinking about making it longer and making the hole little bit bigger dan the original. or can someone give me a drawing of a fmf muffler or so? so i can make a reference

thanks in advance
sixtyfive.

 

[xkevenx]

nobody?

 

[BSWIFT]

There is alot of design characteristics that you need to consider. The most prevalent thing is scavaging. If you reduce or expand the volume of the pipe improperly, the scavenging will be greatly effected, thus reducing power and efficiency. Maintaining the balance of volume and resonance is crucial to proper pipe design and allowing the pipe to fit the bike cleanly is something the aftermarket pipe manufactures spend lots of R & D on. You can do "trial and error" but without knowing what your are trying to achieve and where to attack the design, you are really whizzing into the wind.

 

[BSWIFT]

PS: I am no expert. I've read many articles in the forums about two stroke theory and operation. The availability of good articles and explanations are on the web and maybe even in the archives of DRN. Creating or modifying a two stroke pipe is achievable and with proper knowledge of the theory can provide results that arrive at your intent. Blindly modifying will produce unpredictable results, most likely undesirable. I'm not trying to discourage you. Do more research before putting your welding skills to work. It will be time well spent and possibly produce results that are favorable.

 

[wileyE]

65, think your idea of making it bigger in diam if built longer is good. The thought being not to introduce more back pressure (then stock) with the added length. The stinger diameter of the pipe may help you decide if a bigger diam is needed (backpressure wise), if it's relatively small in comparison I doubt you'd need a bigger core.

One of you limiting factors will be the availability of different size perforated core tubing. You can do the math and theory and come up with numbers, but in the end you make a decision based on whats available for stock (even the big boys are limited by this). This assumes, of course, your building a glass pack style? If your building a baffle design calculating back pressure can get pretty tricky.

Thoughts: Build it to accept a forest service approved tip if you plan to be where it's required. Make it as serviceable as possible for repacking. If you really want to get into it I might have some design software I could share with you. It's more for predicting sound attenuation at different frequency's than actual "how to". I was working on a pressure rebounding exhaust system based on silencing and vibration reduction technology used in high pressure gas lines. There's a couple company's that have picked up on it now so I don't mess with it anymore.

 

[xkevenx]

thanks for the replies, but now i see it is very difficult to make such a thing. i was thinking to take a diameter like 1 inch bigger than the original and 3 of 4 inches longer. i made an alluminium pipe on a four stroke once that was very fatty :d very wide opening and noticable longer. and man that pipe gave me the tors i needed. now i am trying to make such a thing for my two stroke out of stainless steel couse its harder and gives you that brwaap noise :p an second of all im going to take smaler size perforated plate steel and roll it like a burrito :p and i can tell you the results afterwards. my opinion is that the bike will have less dampening and that factory sound, and because the pipe is longer the gasses should be pressing the same like he used too i think; so maybe im trying to make the hole a little bit smaller. i dont know yet.