Question about engine size and tunepipe...
08-19-2005, 08:18 PM
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Question about engine size and tunepipe...
I like to know one thing guys...
If for example a person have a 26cc engine, could he use a goped tune-pipe made for 49cc engine ?
I don't know how 2stroke work exactly, but isn't there a need for special resistance inside the pipe to give best performance? And using a pipe made for 40-50cc engine wouldn't have that resistance a 26cc engine needs to work optimal, or am i way off ?
Please explain this to me, and how far from the engine the big chamber should be for optimal performance.. not exactly, just a estimate on how long the standard size pipe could be, before it needs to have a bigger compartment like the bulky chamber we see in all the tune-pipes.
It's late, so bare with me... maybe some of this is just me talking in my sleep
but i hope you got the general idea of what info I'm after.
I'm not building a pipe, i would like to try something different, and keep in mind, the size is not a problem
If for example a person have a 26cc engine, could he use a goped tune-pipe made for 49cc engine ?
I don't know how 2stroke work exactly, but isn't there a need for special resistance inside the pipe to give best performance? And using a pipe made for 40-50cc engine wouldn't have that resistance a 26cc engine needs to work optimal, or am i way off ?
Please explain this to me, and how far from the engine the big chamber should be for optimal performance.. not exactly, just a estimate on how long the standard size pipe could be, before it needs to have a bigger compartment like the bulky chamber we see in all the tune-pipes.
It's late, so bare with me... maybe some of this is just me talking in my sleep
but i hope you got the general idea of what info I'm after.I'm not building a pipe, i would like to try something different, and keep in mind, the size is not a problem
08-20-2005, 04:44 AM
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RE: Question about engine size and tunepipe...
automan
you should contact simon at www.sbracing.co.uk i'm sure he will be in a position to tell you.
you should contact simon at www.sbracing.co.uk i'm sure he will be in a position to tell you.
08-20-2005, 06:07 AM
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RE: Question about engine size and tunepipe...
Thanks veron !! I will contact him and see if he has any good explanation.
But the best thing would be if some of the knowledgeable people in here could explain this, i think it would be a useful thread to have here for future reference.
I sure know how the 2stroke engine operates. It's just that I'm not totally sure about this different size of pipes, how it would effect the engines performance.
I would guess that a big pipe for a 40-50cc engine would make a 26-29cc engine weak and you would loose effect, and to small pipe would probably strangle the flow and the engine would just stop from time to time.
These are just my idea of how it works, sure would like to hear from somebody who knows more exactly how it works with the effect from the pipes.
Will contact simon at sbracing right now, and if i get a answer i will post it here for you all. I'm not totally convinced that he would recommend anything but the pipes he sells to the RC cars, but hey.. i will give him a chance
Have a great weekend guys !!!!
But the best thing would be if some of the knowledgeable people in here could explain this, i think it would be a useful thread to have here for future reference.
I sure know how the 2stroke engine operates. It's just that I'm not totally sure about this different size of pipes, how it would effect the engines performance.
I would guess that a big pipe for a 40-50cc engine would make a 26-29cc engine weak and you would loose effect, and to small pipe would probably strangle the flow and the engine would just stop from time to time.
These are just my idea of how it works, sure would like to hear from somebody who knows more exactly how it works with the effect from the pipes.
Will contact simon at sbracing right now, and if i get a answer i will post it here for you all. I'm not totally convinced that he would recommend anything but the pipes he sells to the RC cars, but hey.. i will give him a chance
Have a great weekend guys !!!!
08-20-2005, 10:46 AM
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RE: Question about engine size and tunepipe...
Well, i have taken care of the info i needed, kinda
Basically you need a well tuned pipe for the engine-size you have (a few cc can differ, but not more then 10cc). A short bended pipe with a big chamber will give you mainly improvement in low and midrange, while a long thin pipe gives better high-speed.... not groundbreaking news, but for anyone that are interrested and dont know the basic way of thinking in the right line is now available here
Got the info from goped forums in the UK.
Well all this is what i thought from the beginning, so i have decided to go for a pipe that is designed for my size of engine instead of testing allot of pipes thats made for bigger engine with no success
Veron, i haven't heard back from Simon, but it haven't been so long time since i mailed him so I'm not surprised.
The below info was taken from: http://www.gopednation.com
[b]Here is the info i found:
Have you ever wondered why your tuned pipe is shaped like that? Why it's not shaped like a cat or a can of beer? Or have you wondered why different shaped pipes perform differently? Well here are the answers. A tuned pipe is basicly a turbochager with no moving parts. The pipe uses the force and pressure from the exhuast gasses to sqeeze more air and fuel into the combustion chamber during the intake phase. I'll break it down for you. In two stroke engines the exhaust and intake cycles somewhat overlap. When the piston moves down the exhuast port is opened and lets most of the exhaust gas out, then opens the intake port to let more and and fuel into the combustion chamber. By putting a tuned pipe on the exhaust port you cause the following to happen.
1) When the exhaust gasses enter the expansion chamber they expand (durr) and as they expand a vacuum is formed. The vacuum sucks air and fuel into the intake port and on into the cylinder.
2. As all this is going on a shockwave is also created that echoes from the tip of the pipe back to the exhaust port and pushes any fuel/air that got pulled in past the combustion chamber back into the cylinder. This is why tuned pipes have that "pipey" sound.
3. By sucking and pushing more air into the combustion chamber the engine gets a lot more fuel and air than it normally could.
Like a turbocharger, pipes work best when the engine is at a certain RPM and putting out a certain ammout of exhaust. The way a pipe behaves below its powerband is similar to a turbocharger's turbo lag. When the pipe reaches the point when it is putting out enough exhaust and moving fast enough you get (BINGO!) a powerband. Here's a representation of what you get:
aaawwwwwwwwAWWWWWWWWWEEEEEEEEE EEEEEEEEEEEEEEEE!!!
(the "lag") (almost there) (powerband!)
The "EEEEE's" come at different places with different pipes some pipes, on certain engines, hit more than one band at different RPM. Pipes have four basic parts:
1. The Inlet- The part that leads from the exhaust port to the expansion chamber
2. Divergent Cone(s)- The part of the pipe that changes in diameter from the inlet to the belly or expansion chamber and back to the tip of the pipe. Some pipe's divergent cones are more pronounced than others. Some pipes only have one.
3. Belly- The part of the pipe where the exhaust gasses expand.
4. Stinger- Where the exhaust gasses escape the pipe.
Lets take some common examples for the pipes we use. I'll be very general since pipes are tailored for a certain powerband.
1. Engine Trix- Short inlet and divergence cones. Large belly. This pipe is designed to hit low in the engine's RPM curve. It's fat belly allows the pipe to echo and expand gas at a lower RPM.
2. Flowsystem- This pipe is unique in that it is tuned to work best on the 4-port G230RC. It has a long inlet and divergent cones. The belly is long and skinnier than the Engine Trix. As anyone who has used this pipe knows, this pipe is designed for TOP END. The skinnier, longer demensions are suited for putting out power at higher RPM, but has an almost non-existant low end.
3. PPS- This pipe is very small and hits the higest out of the three. It it very hard at high RPM which leads us to infer that this pipe puts out its power best at only a very specific part of the engine's RPM range.
So basicly...
Fat pipe= Torque
Skinny pipe= High RPM
There are many, many pipes that are in between but that's the basics. As for which pipe is best it's all up to your riding style. Some people like a powerband that hits real low out of corners allowing them to slow down and take an inside line then punch the gas and get on the band to shoot out of the corners. Others like the kind of powerband that hits at high RPM. That way they can carry speed into the corner, take an outer line and stay on the band the whole time.
b]
just to add info to pedderdaves article if this becomes a sticky..
These engines are based on Volumetric Efficiency, which is the ratio of the actaul amount of air drawn into an engine versus the capacity of the engine. Natural V.E of a two stoke is about 65% ( ex. a 250cc cylinder only draws about 160cc air). The HP output of an engine can be raised by increasing V.E.
When the exhuast port is oponed, sonic wave is generated by high pressure exhuast gases expanding into the header pipe at about 1700 FT per Sec.
Waves travel down the header, expands into the diverging cone cuasing a negative pressure ( @7psi) The negative pressure pulls exhuast particles out of the cylinder and helps draw in fresh charge through transfers.
Sonic waves hit the converging cone and positive pressure is reflected back towards exhuast port.
If the length of the pipe is tuned correctly, postive pressure returns to the header pipe just before exhuast port closes and pushes fresh charge that has escaped into the header back into the cylinder
the pipe then bleeds down to approximately atmosheric pressure and the cycle is repeated.
Also the design of the pipe depends upon many factors such as bore, stroke and desired operating RPM range. The sonic wave speed is fairly consistant, length of the pipe is a large factor in controlling engine RPM at which the pipe will be consistant
I wish I had a picture of a basic pipe design so you guys would understand this more.
It starts with the header section then a diverging cone to a belly section and then a converging cone followed by a stinger ( outlet).
Basically you need a well tuned pipe for the engine-size you have (a few cc can differ, but not more then 10cc). A short bended pipe with a big chamber will give you mainly improvement in low and midrange, while a long thin pipe gives better high-speed.... not groundbreaking news, but for anyone that are interrested and dont know the basic way of thinking in the right line is now available here
Got the info from goped forums in the UK.Well all this is what i thought from the beginning, so i have decided to go for a pipe that is designed for my size of engine instead of testing allot of pipes thats made for bigger engine with no success
Veron, i haven't heard back from Simon, but it haven't been so long time since i mailed him so I'm not surprised.
The below info was taken from: http://www.gopednation.com
[b]Here is the info i found:
Have you ever wondered why your tuned pipe is shaped like that? Why it's not shaped like a cat or a can of beer? Or have you wondered why different shaped pipes perform differently? Well here are the answers. A tuned pipe is basicly a turbochager with no moving parts. The pipe uses the force and pressure from the exhuast gasses to sqeeze more air and fuel into the combustion chamber during the intake phase. I'll break it down for you. In two stroke engines the exhaust and intake cycles somewhat overlap. When the piston moves down the exhuast port is opened and lets most of the exhaust gas out, then opens the intake port to let more and and fuel into the combustion chamber. By putting a tuned pipe on the exhaust port you cause the following to happen.
1) When the exhaust gasses enter the expansion chamber they expand (durr) and as they expand a vacuum is formed. The vacuum sucks air and fuel into the intake port and on into the cylinder.
2. As all this is going on a shockwave is also created that echoes from the tip of the pipe back to the exhaust port and pushes any fuel/air that got pulled in past the combustion chamber back into the cylinder. This is why tuned pipes have that "pipey" sound.
3. By sucking and pushing more air into the combustion chamber the engine gets a lot more fuel and air than it normally could.
Like a turbocharger, pipes work best when the engine is at a certain RPM and putting out a certain ammout of exhaust. The way a pipe behaves below its powerband is similar to a turbocharger's turbo lag. When the pipe reaches the point when it is putting out enough exhaust and moving fast enough you get (BINGO!) a powerband. Here's a representation of what you get:
aaawwwwwwwwAWWWWWWWWWEEEEEEEEE EEEEEEEEEEEEEEEE!!!
(the "lag") (almost there) (powerband!)
The "EEEEE's" come at different places with different pipes some pipes, on certain engines, hit more than one band at different RPM. Pipes have four basic parts:
1. The Inlet- The part that leads from the exhaust port to the expansion chamber
2. Divergent Cone(s)- The part of the pipe that changes in diameter from the inlet to the belly or expansion chamber and back to the tip of the pipe. Some pipe's divergent cones are more pronounced than others. Some pipes only have one.
3. Belly- The part of the pipe where the exhaust gasses expand.
4. Stinger- Where the exhaust gasses escape the pipe.
Lets take some common examples for the pipes we use. I'll be very general since pipes are tailored for a certain powerband.
1. Engine Trix- Short inlet and divergence cones. Large belly. This pipe is designed to hit low in the engine's RPM curve. It's fat belly allows the pipe to echo and expand gas at a lower RPM.
2. Flowsystem- This pipe is unique in that it is tuned to work best on the 4-port G230RC. It has a long inlet and divergent cones. The belly is long and skinnier than the Engine Trix. As anyone who has used this pipe knows, this pipe is designed for TOP END. The skinnier, longer demensions are suited for putting out power at higher RPM, but has an almost non-existant low end.
3. PPS- This pipe is very small and hits the higest out of the three. It it very hard at high RPM which leads us to infer that this pipe puts out its power best at only a very specific part of the engine's RPM range.
So basicly...
Fat pipe= Torque
Skinny pipe= High RPM
There are many, many pipes that are in between but that's the basics. As for which pipe is best it's all up to your riding style. Some people like a powerband that hits real low out of corners allowing them to slow down and take an inside line then punch the gas and get on the band to shoot out of the corners. Others like the kind of powerband that hits at high RPM. That way they can carry speed into the corner, take an outer line and stay on the band the whole time.
b]
just to add info to pedderdaves article if this becomes a sticky..
These engines are based on Volumetric Efficiency, which is the ratio of the actaul amount of air drawn into an engine versus the capacity of the engine. Natural V.E of a two stoke is about 65% ( ex. a 250cc cylinder only draws about 160cc air). The HP output of an engine can be raised by increasing V.E.
When the exhuast port is oponed, sonic wave is generated by high pressure exhuast gases expanding into the header pipe at about 1700 FT per Sec.
Waves travel down the header, expands into the diverging cone cuasing a negative pressure ( @7psi) The negative pressure pulls exhuast particles out of the cylinder and helps draw in fresh charge through transfers.
Sonic waves hit the converging cone and positive pressure is reflected back towards exhuast port.
If the length of the pipe is tuned correctly, postive pressure returns to the header pipe just before exhuast port closes and pushes fresh charge that has escaped into the header back into the cylinder
the pipe then bleeds down to approximately atmosheric pressure and the cycle is repeated.
Also the design of the pipe depends upon many factors such as bore, stroke and desired operating RPM range. The sonic wave speed is fairly consistant, length of the pipe is a large factor in controlling engine RPM at which the pipe will be consistant
I wish I had a picture of a basic pipe design so you guys would understand this more.
It starts with the header section then a diverging cone to a belly section and then a converging cone followed by a stinger ( outlet).
08-20-2005, 04:41 PM
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RE: Question about engine size and tunepipe...
Hello Automan
Try a MICRON with the main section cut out and replace it with a Yammy FS1E baffle we are talking bikes now?
Regards
Vo0[&:]
Try a MICRON with the main section cut out and replace it with a Yammy FS1E baffle we are talking bikes now?
Regards
Vo0[&:]
08-20-2005, 05:06 PM
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RE: Question about engine size and tunepipe...
Has anyone tried the pipe from the old Raco Jackrabbit on their 230 or 260's? Another question on exhausts. How can one get top performance using only the standard can muffler on the Zenoah's?
08-20-2005, 08:44 PM
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RE: Question about engine size and tunepipe...
voo2doo, they are.... we are not. but it's the same basic idea, and i thought i could be useful reading up some basic thoughts and how it works. Would like to build my own tunepipe, could do it up in the computer, but i have not got the tools to make one
daytona7, i know someone here have mentioned how to fix up the standard muffler, but i cant find it now :/ I cant remember if he gave out the detailed description on how to do it, or if he just mentioned it could be done.
I think it is possible to juice it up some, but i haven't tried it, as I'm not looking for a cheap easy fix to boost up a little performance, i want the best possible.. and that will most certainly require buying a topline tunepipe, they cost a little, but you usually can use them for almost a whole year [sm=thumbup.gif]
About the Raco Jackrabbit, you're not referring to the post in here around christmas about a boatpipe someone had converted to their Jacko ?
daytona7, i know someone here have mentioned how to fix up the standard muffler, but i cant find it now :/ I cant remember if he gave out the detailed description on how to do it, or if he just mentioned it could be done.
I think it is possible to juice it up some, but i haven't tried it, as I'm not looking for a cheap easy fix to boost up a little performance, i want the best possible.. and that will most certainly require buying a topline tunepipe, they cost a little, but you usually can use them for almost a whole year [sm=thumbup.gif]
About the Raco Jackrabbit, you're not referring to the post in here around christmas about a boatpipe someone had converted to their Jacko ?
