hi i run my 66cc with out baffles in the exhaust and hit up to 51 kph or 37 with baffles lol ,does anyone know of an exhaust system thats cheap and has a good power increase? (other than expansion chamber) , cheers 
upgraded exhausts that are not too loud and gain more power?
- Thread starter joshua97
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Deleted member 12676
Guest
For a power increase you have to modify the standard exhaust. click onto my signature link.
Fabian
Well-Known Member
2.5 feet of flexible high temperature silicone hose will dramatically quieten exhaust noise
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Deleted member 12676
Guest
I bought a db noise meter and know for a fact that a normal expansion chamber and a normal silencer is way too loud for anywhere other than the motocross track.
That's why I researched the belly stinger and other forms of silencing so people can have the power without the noise.
I have a new design of silencer that I've been testing on my Suzuki and it is free flowing and very quiet, a real breakthrough. But until I make construction plans available you can still use my other design that is on my site.
Using the belly stinger and my stealth silencer is good but still on the edge of just barely being acceptable for street use. I can't imagine using anything less.
That's why I researched the belly stinger and other forms of silencing so people can have the power without the noise.
I have a new design of silencer that I've been testing on my Suzuki and it is free flowing and very quiet, a real breakthrough. But until I make construction plans available you can still use my other design that is on my site.
Using the belly stinger and my stealth silencer is good but still on the edge of just barely being acceptable for street use. I can't imagine using anything less.
Nature girl
Member
I haven't tried it, but jaguar's design looks legit.
i believe you about normal expansion chambers being too loud. my own data come from a kludged together pseudo expansion chamber solution i put together in a rush to get my ride working. it consists of the 'skeleton,' which i mad by crafting a primitive expansion chamber out of steel cans (there's a post about it in my history) bent into shape, with a minimal silencer part at the end - top 1/3 of 23oz aluminum can with half a steel scrubber stuffed in and tacked on place. it didn't seal, not even close like that, so I built it up using layers of aluminum foil and cold weld exhaust&muffler repair putty. after enough of this heat shielding, I cheated and used Bondo, plus more foil. all this material seemed sufficient heat shielding, but it seemed maybe a little bit brittle and was still pretty loud, but already several dB better than straight pipe or expansion chamber alone. so I added couple layers of furnace tape and duct tape, and actually I put more Bondo, stretched part of a broken inner tube over the whole thing, added one more layer of Bondo and foil, put some more tape and painted it. it's pretty dang quiet now and feels pretty solid and stable.
I was a little uneasy about the safety and integrity of using rubber in there like that, so I can't recommend it at this point, though it's worked well for me for the past four or five hundred miles (trips up to 15 or 20 min, WOT for maybe 15-20% of that, probably 4 or 5 min at the longest stretch)
Jaguar points it out on his site that an expansion chamber tends to be loud because the walls of it will flex from the pressure and reverberate like a drum or loudspeaker, sending out intense noise that bypasses the silencer completely. that's 100% right. what I'm saying is that layers of heat and acoustic shielding can be wrapped around the pipe and chamber to cut down this sound too. it's even easier than making a silencer muffler, though I'd urge you to make yours hopefully a bit more professionally than how I made mine though...
i believe you about normal expansion chambers being too loud. my own data come from a kludged together pseudo expansion chamber solution i put together in a rush to get my ride working. it consists of the 'skeleton,' which i mad by crafting a primitive expansion chamber out of steel cans (there's a post about it in my history) bent into shape, with a minimal silencer part at the end - top 1/3 of 23oz aluminum can with half a steel scrubber stuffed in and tacked on place. it didn't seal, not even close like that, so I built it up using layers of aluminum foil and cold weld exhaust&muffler repair putty. after enough of this heat shielding, I cheated and used Bondo, plus more foil. all this material seemed sufficient heat shielding, but it seemed maybe a little bit brittle and was still pretty loud, but already several dB better than straight pipe or expansion chamber alone. so I added couple layers of furnace tape and duct tape, and actually I put more Bondo, stretched part of a broken inner tube over the whole thing, added one more layer of Bondo and foil, put some more tape and painted it. it's pretty dang quiet now and feels pretty solid and stable.
I was a little uneasy about the safety and integrity of using rubber in there like that, so I can't recommend it at this point, though it's worked well for me for the past four or five hundred miles (trips up to 15 or 20 min, WOT for maybe 15-20% of that, probably 4 or 5 min at the longest stretch)
Jaguar points it out on his site that an expansion chamber tends to be loud because the walls of it will flex from the pressure and reverberate like a drum or loudspeaker, sending out intense noise that bypasses the silencer completely. that's 100% right. what I'm saying is that layers of heat and acoustic shielding can be wrapped around the pipe and chamber to cut down this sound too. it's even easier than making a silencer muffler, though I'd urge you to make yours hopefully a bit more professionally than how I made mine though...
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butre
Well-Known Member
my custom expansion chamber peaks at 96 db which osha says you can be exposed to for 8 hours a day without hearing damage with the only noise reducing feature being a stinger placed 6 inches into the pipe. I plan on eventually wrapping it to reduce the noise further. I may install an actual muffler eventually as well.
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Deleted member 12676
Guest
94 db is the noise limit for motocross !! (at 20" away at 45 degrees)
It's very loud.
My torque pipe with stealth silencer puts out half as much noise as a 94db setup.
It's very loud.
My torque pipe with stealth silencer puts out half as much noise as a 94db setup.
