Expansion Chamber
- Thread starter misteright1_99
- Start date
Nice Bike Hookworm! I can tell that's one of Dean's pipes. How's the low end?
Some time ago I was at this electronic tech store that had loads of tech books.
The books weren't all about electronics thought. There were some on motorcycles and building expansion chambers.
There was loads of formula and higher math calculations to go thru.
It seems that you build a chamber for any "one" of the below:
1) torque
2) low end
3) mid range
4 top end
the torque tube just adds more torque all across the spectrum as soon as you bolt it on.
The others are "Peaky" meaning that they get a surge of power in that rpm band. Often the tuner will play with going up or down a couple of teeth on the front sprocket to widen that bost out to where it's more mellow or last thru the range of the gear to wind out.
But I'd say some math skills, algebra, and possibly some simple calculus could be used to lay out chambers for various cc displacements.
I went searching for Expansion Chamber design &fabrication data and found this:
It's a 1.5 Mb zip file so you'll need a free unzip utility like coffeecup's or others if you don't already have one. (CoffeeCup's free zip wizard is : CoffeeCup Free Zip Wizard - Zipping and Un-Zipping has never been easier !
I downloaded mine and will unzip and look thru it later as I can.
I can imagine modeling these things to fit the bike with the least curves to make it buildable. Then there's the issue of a silencer cause it'll sound like a chain saw without one.
The books weren't all about electronics thought. There were some on motorcycles and building expansion chambers.
There was loads of formula and higher math calculations to go thru.
It seems that you build a chamber for any "one" of the below:
1) torque
2) low end
3) mid range
4 top end
the torque tube just adds more torque all across the spectrum as soon as you bolt it on.
The others are "Peaky" meaning that they get a surge of power in that rpm band. Often the tuner will play with going up or down a couple of teeth on the front sprocket to widen that bost out to where it's more mellow or last thru the range of the gear to wind out.
But I'd say some math skills, algebra, and possibly some simple calculus could be used to lay out chambers for various cc displacements.
I went searching for Expansion Chamber design &fabrication data and found this:
The page is at: http://www.bevenyoung.com.au/mota.htm
It's a 1.5 Mb zip file so you'll need a free unzip utility like coffeecup's or others if you don't already have one. (CoffeeCup's free zip wizard is : CoffeeCup Free Zip Wizard - Zipping and Un-Zipping has never been easier !
I downloaded mine and will unzip and look thru it later as I can.
I can imagine modeling these things to fit the bike with the least curves to make it buildable. Then there's the issue of a silencer cause it'll sound like a chain saw without one.
One of my first dirt bikes was a Yamaha 90 enduro. When I put a mid range chamber on it the chamber had what looked like a 20 gage shotgun barrel
sticking out of it and it was LOUD !
I liked it but the dogs and neighbors didn't. So I go out to the sand and gravel
place and ride the begeez out of it. But after awhile I started getting headaches from it. (not to mention the neighborhood)
So I got this silencer that clamped on over the end of the tube and it cut the noise way down. It was a different world after that.
I'd mention that as these machines become more and more abundant that there will be those who complain of the noise they make. It may be prudent for us to consider chaperoning our own machines when out in public before authorities see an industry and $$$ traffic revenue in chaperoning them for us. (and at worst.......confiscating them because of the noise they make in public)
Alot of the guys on the Harleys pull the mufflers off them and replace them with straight (and very loud) pipes. Often they wear Tee shirts that proclaim
"Loud Pipes Save Lives". But it is right on the mufflers where it is unlawful to replace mufflers with straight pipes and may be a $10, 000 dollar fine. Still folks do it and ride thru the down town areas grabbing a handfull when the light turns green to make an echo chamber of the business sector.
I'm not making any judgement.....just the observation of the experiences I've had with bikes, the noise they make, and cops.
sticking out of it and it was LOUD !
I liked it but the dogs and neighbors didn't. So I go out to the sand and gravel
place and ride the begeez out of it. But after awhile I started getting headaches from it. (not to mention the neighborhood)
So I got this silencer that clamped on over the end of the tube and it cut the noise way down. It was a different world after that.
I'd mention that as these machines become more and more abundant that there will be those who complain of the noise they make. It may be prudent for us to consider chaperoning our own machines when out in public before authorities see an industry and $$$ traffic revenue in chaperoning them for us. (and at worst.......confiscating them because of the noise they make in public)
Alot of the guys on the Harleys pull the mufflers off them and replace them with straight (and very loud) pipes. Often they wear Tee shirts that proclaim
"Loud Pipes Save Lives". But it is right on the mufflers where it is unlawful to replace mufflers with straight pipes and may be a $10, 000 dollar fine. Still folks do it and ride thru the down town areas grabbing a handfull when the light turns green to make an echo chamber of the business sector.
I'm not making any judgement.....just the observation of the experiences I've had with bikes, the noise they make, and cops.
looks good hookworm! lets see some more close-up pics , thats a nice exhaust shield!
"ride it like you stole it"
"ride it like you stole it"
Well, I had some time while ago to unzip that Expansion Chamber Design Editor from the post above. pipe_dns.zip of 1.5Mb. It's straight foreward enough but I'm not sure about the horse power we're running with our projects. We may have to double the HP of our motors (or 10X) to enter so the software will accept it and at the other end divide the diameters and lengths by half or 10. So with all things being equal we may be able to get some workable figures it.
When you open it this is what it looks like:
The program is straight foreward and if you can use a caliper to take measurements on your engine and a piece of wire to feel into a port to a piston (and measure that distance with your caliper) you can probably use this software. The other values are probably in your owners manual or on a plate on the motor or housing. I would advise
trying to build the chamber as straight inline as possible so it can mount to the cylinder and toward the back on the frame running at an upward diagonal like dirt bike. It will be easier to build and mount and clear the pedals better. If you have a successful build, then a heat shield could be built of perferated sheet metal to cover the area where you inside leg would need a 1/2 inch barrier from the hot chamber.
This even lays out the profile for your expansion chamber for you at the bottom. Even sweeter is the Print button so you can print the chamber and spec's required to build it.
But since in Ahio we can only have 1 hp motors and this software wants HP values of 8 to 12+ I'll be "doubling and halfing" (or 10Xing) my math to walk the calcultions thru the editor. (then dividing by 1/10 the measurment it kicks out at the end.
Otherwise this is a slick little piece of FREE software.
When you open it this is what it looks like:
The program is straight foreward and if you can use a caliper to take measurements on your engine and a piece of wire to feel into a port to a piston (and measure that distance with your caliper) you can probably use this software. The other values are probably in your owners manual or on a plate on the motor or housing. I would advise
trying to build the chamber as straight inline as possible so it can mount to the cylinder and toward the back on the frame running at an upward diagonal like dirt bike. It will be easier to build and mount and clear the pedals better. If you have a successful build, then a heat shield could be built of perferated sheet metal to cover the area where you inside leg would need a 1/2 inch barrier from the hot chamber.
This even lays out the profile for your expansion chamber for you at the bottom. Even sweeter is the Print button so you can print the chamber and spec's required to build it.
But since in Ahio we can only have 1 hp motors and this software wants HP values of 8 to 12+ I'll be "doubling and halfing" (or 10Xing) my math to walk the calcultions thru the editor. (then dividing by 1/10 the measurment it kicks out at the end.
Otherwise this is a slick little piece of FREE software.
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What do we think about adapting the grubee long chrome muffler with an expansion chamber, it would look real clean and would fit in well with a cruiser bike.
Hey, so what bike did you get this one off of (or what ebay auction?) I've got a 65cc tuned pipe coming that I'm going to try to fit to my 67cc HT, but its going to take a lot of cutting and rotating to get the exhaust routed properly. Should be better than stock at least.
For those who are interested in explansion chambers I'm posting a link to a small web site that has an animation of how it all works, with an expansion chamber. Mufflers only quieten the sound. shown are cut away views of carb, engine, and chamber. It's in color and watching it for a few seconds can explain much.
As I mentioned before there are expansion chambers for low range performance, mid range, (which I used) and high rpm range. There is also
what's called a "Torque Chamber" and it is what's shown in the site. (it has the parallel spacer in the tube where "range" chambers are made of all tapering sections of tubing. The torque chamber increases torque accross all RPM ranges. You don't feel a boost of power like you do with an RPM range oriented chamber.
I don't know if anyone downloaded the free expansion chamber design software I posted the link to a few post back. My little motor is just 30 some cc's so I'd have to multiply several times by the software's size thresholds to design a system and then reduce it by the same factor to keep it to scale.
But give this a look:
A RUNNING 2 STROKE ENGINE:
A two-stroke
As I mentioned before there are expansion chambers for low range performance, mid range, (which I used) and high rpm range. There is also
what's called a "Torque Chamber" and it is what's shown in the site. (it has the parallel spacer in the tube where "range" chambers are made of all tapering sections of tubing. The torque chamber increases torque accross all RPM ranges. You don't feel a boost of power like you do with an RPM range oriented chamber.
I don't know if anyone downloaded the free expansion chamber design software I posted the link to a few post back. My little motor is just 30 some cc's so I'd have to multiply several times by the software's size thresholds to design a system and then reduce it by the same factor to keep it to scale.
But give this a look:
A RUNNING 2 STROKE ENGINE:
A two-stroke
For those who are interested in explansion chambers I'm posting a link to a small web site that has an animation of how it all works, with an expansion chamber. Mufflers only quieten the sound. shown are cut away views of carb, engine, and chamber. It's in color and watching it for a few seconds can explain much.
As I mentioned before there are expansion chambers for low range performance, mid range, (which I used) and high rpm range. There is also
what's called a "Torque Chamber" and it is what's shown in the site. (it has the parallel spacer in the tube where "range" chambers are made of all tapering sections of tubing. The torque chamber increases torque accross all RPM ranges. You don't feel a boost of power like you do with an RPM range oriented chamber.
I don't know if anyone downloaded the free expansion chamber design software I posted the link to a few post back. My little motor is just 30 some cc's so I'd have to multiply several times by the software's size thresholds to design a system and then reduce it by the same factor to keep it to scale.
But give this a look:
A RUNNING 2 STROKE ENGINE:
A two-stroke
Thanks for informative post, I have good idea how a two stroke egine works, but I was wondering about the benfits of an expansion chamber.
lestat101, the very last image at the bottom of that web site is an animation
of a 2 cycle engine equipped with an expansion chamber. If you watch it you can see what an expansion chamber does for a 2 cycle engine. Of course the web site has to make the assumption that a person may not know much about how 2 cycle engines work. It just takes a little time for the animation to load so you can see it work.
In the animation it shows how the chamber keeps more fuel air mixture in the combusition chamber that would otherwise be lost by a conventional muffler.
I've has several expansion chambers on my 2 stroke bikes.
Mr Larkins, I've seen those books you speak of but not recently. Lots of formula's and calculations. Then you only need a slip roller, some sheet metal, and light brazing or welding equipment. The free software I posted a few post back from IWT Racing lends itself to larger displacement engines, but by "doubling & halving system math" or Calculus one could calculate a basic performance profile expansion chamber and scale it to a family of engine displacements.
Something to look at:
Howstuffworks
of a 2 cycle engine equipped with an expansion chamber. If you watch it you can see what an expansion chamber does for a 2 cycle engine. Of course the web site has to make the assumption that a person may not know much about how 2 cycle engines work. It just takes a little time for the animation to load so you can see it work.
In the animation it shows how the chamber keeps more fuel air mixture in the combusition chamber that would otherwise be lost by a conventional muffler.
I've has several expansion chambers on my 2 stroke bikes.
Mr Larkins, I've seen those books you speak of but not recently. Lots of formula's and calculations. Then you only need a slip roller, some sheet metal, and light brazing or welding equipment. The free software I posted a few post back from IWT Racing lends itself to larger displacement engines, but by "doubling & halving system math" or Calculus one could calculate a basic performance profile expansion chamber and scale it to a family of engine displacements.
Something to look at:
Howstuffworks
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I didnt like the noise level so I built a silencer that was almost double the inside diameter so I could get more packing in and give the ehaust more room to expand before leaving. MUCH quieter, and still sounds GREAT....My bike sounds just like a chainsaw... & I love it!!
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What did you use for packing material? I've got some fiberglass cloth left over from a ways back and I was thinking of sticking a little of that in my muffler.
I've found that most of the noise that comes from my bike comes from the cylinder itself, not the exhaust. Til my exhaust pipe falls off (again) anyway But since I lengthened my exhaust, I get a more snappy tone from the muffler, and I'd like to get rid of that.
An expansion chamber would be nice, but my wife is still mad at me for getting the bike in the first place, so yeah :-/
I've found that most of the noise that comes from my bike comes from the cylinder itself, not the exhaust. Til my exhaust pipe falls off (again) anyway
But since I lengthened my exhaust, I get a more snappy tone from the muffler, and I'd like to get rid of that.An expansion chamber would be nice, but my wife is still mad at me for getting the bike in the first place, so yeah :-/
I tried using some fiberglass cloth on the old silencer and the larger one, and it was louder than the packing that came with the pipe. I ended up using fiberglass wall insulation packed very loosley and with the larger size made alot of difference. I just dont want to attract attention or piss off the neighbors....As for engine/cylinder noise I used tubing between every other fin to dampen that noise....
hmm, well considering my muffler has no packing right now, I guess the cloth should at least make a little difference
