make your own torque pipe

Discussion in 'Performance Mods' started by jaguar, Jun 27, 2012.

  1. jaguar

    jaguar Well-Known Member

    All the pipes sold for these engines are made for pocketbike racers, not for low rpm single speed street bikes. A racing pipe only enhances top rpm power (if the header length is correct for the engine specs and top rpm). My latest design enhances low rpm power without detracting from top rpm power. I´m giving the design away here. Pipes arent too hard to make. Just takes patience and determination. The sheet metal ideally should be steel of .7mm thickness. Someone told me that the steel from a water heater is just about right. If you buy a sheet then it should be the kind that rusts since it is easiest to weld. You can use tin snips to cut the pieces out. A computer program can printout the pieces on paper that you can use as patterns. I use a rubber mallet, pliers, and needle nose pliers to bend the pieces. I use a bicycle fork to bend the pieces onto by hammering the piece while it rests on the fork. Other metal cylinders of various diameters can also be used. You will need to find someone with an oxyacetylene welder to weld it together. Emphasis to them that it needs to be lightly welded so that little "slag" extends inside the pipe. For an upswept pipe you can cut off the std muffler for the first section. Second section is only the curved header pipe from a standard muffler, 6.5" long (centerline). This sets the correct tuned distance for around 6000 rpm max. For a muffler you can make a cylinder with removable metal scouring pads inside it. Just put small holes in the end of it. Less holes is less noise.
    There is no feeling equal to having your own handmade expansion chamber on your pipe and feeling the difference it makes. I knew nothing about making them but I just dived in and did it. Anyone with one brain and two hands can make one.
    I used my newly created Excel files to come up with these dimensions. Click here to read about how expansion chambers work and how extending the last cone (the baffle) extends the pipes powerband.
    enjoy
    48ccTpipe.jpg
     
    Last edited: Jun 27, 2012

  2. Fabian

    Fabian Well-Known Member

    That's very handy information Jaguar.

    What about torque pipe dimensions for the 66cc engine (47mm bore and 38mm stroke) with maximum torque set for 3,800 rpm?
     
  3. jaguar

    jaguar Well-Known Member

    At the bottom right of the diagram page you can see the two changes you need to make for the same pipe to work with a 66cc engine. If all you had is a header and muffler then you will be pleasantly surprised at how much the power is enhanced at all rpm, even more so if you have a reed valve. (Why? a reed valve allows more intake into the crankcase and cylinder when the suction wave from the diffuser arrives back at the cylinder. with a piston port intake all the suction wave does is prevent the intake charge from being drawn back down into the crankcase as the piston ascends after BDC.)
     
  4. Fabian

    Fabian Well-Known Member

    Jaguar, can you please make a youtube video of the build process, showing the start to finish manufacturing of the torque pipe, explaining the various steps and metal bending techniques as you create, assemble and weld the pipe together out of it's component sections.

    This is desperately needed, and i'm sure you have the technology to make it happen.

    I'm keenly waiting so i can watch the process.

    Kind regards
    Fabian
     
  5. jaguar

    jaguar Well-Known Member

    Here's a pic of a similar pipe on my 55cc bike. It has two diffuser cones and two baffle cones separated with a 40mm extension. But I regret making the stinger the old fashioned way that causes the exhaust pulse to be concentrated and impossible to reduce to a quiet level. (The noise even with my prototype Russian silencer is excessive.) I'm going to cut off the stinger, weld shut the end of the pipe, drill a 14mm hole in the belly (midsection), and have a channel welded to the underside of the pipe till it can connect to the cut-off stinger. Noise is about half when the stinger originates from the belly. Exiting from the end cone is OK for racing pipes but crazy crazy for street bikes. Performance wise there is not one reason the exit tube should begin at the end cone. Torque is increased a bit when it originates from the belly and there is no reduction of peak power. I know this from experience with my Jaguar Pipe but the idea came from writings of Jennings. So any pipe with torque as its goal should have a "belly stinger". I claim temporary insanity. If you look closely there is a welding seam at the midpoint of the belly. That is because I designed the pipe so my leg won't touch it occassionally like happened with my last pipe. The belly first angles downward and then off to the left. I had to make the belly in two sections to accomplish that. I just tested it and it was perfect for use on the street. :)
    View attachment 45165
    6-12pipeonly.jpg
     
  6. Fabian

    Fabian Well-Known Member

    Excellent work Jaguar.

    Great to hear that you're designing a pipe to have very low noise levels.
    The way governments are introducing nasty and draconian legislation to effectively ban motorized bicycles with an internal combustion engine, it's nice to know (and appreciated) that someone is making a performance enhancing product that is suited for lower rpms and lower noise levels.

    Can you please make a youtube video so we can watch the pipe being fabricated, welded/assembled and the theory of a belly mounted exhaust location explained along with the dimensions.
     
  7. jaguar

    jaguar Well-Known Member

    The belly area is where the exhaust pulse is most expanded and therefore has less pressure. It's the sudden release of pressure into the air that creates sound, which is in essence a pressure wave. So the less pressure is released, the less noise (unwanted sound). Letting the stinger start at the belly insures that the pressure pulse is much less than that which would exit the end of the pipe. The torque pipe has a 10.6mm internal stinger diameter and a 42.1mm internal belly diameter. That translates to areas of 88 and 1392 square millimeters cross sectional area. 1392 divided by 88 is 15.8. So theoretically the exhaust pulse at the belly is almost 16 times less dense than that at the end of the baffle cone. So it's easy to see how pipes can be much quieter by having a belly stinger instead of an end-baffle stinger. There's an extra benefit for a torque pipe also. Exiting the gas at the belly means there is no flow in the baffle, only pressure. So there is less heat. Less heat means the sound wave travels slower in the baffle section, broadening the baffle powerband even more. And a bit more powerband stretching can be had by making the baffle come to a point because that extends its length.
    I will see if I can make a video showing how I form one of the cones. Here's a picture of someone welding using acetylene: Picture 16.jpg
     
  8. Fabian

    Fabian Well-Known Member

    Please make a complete video showing the start to finish process...
     
  9. jaguar

    jaguar Well-Known Member

    Here is pics showing how I am converting this pipe to having a belly stinger. They show the hole I drilled in the belly, the stinger channel I will have welded to the pipe, and the end of the channel where I will transfer the existing stinger to it by cutting and welding.
    pipemod1.jpg pipemod2.jpg pipemod3.jpg
     
  10. Fabian

    Fabian Well-Known Member

    Great idea Jaguar - now please make a start to finish youtube video where you cut out the panels for the pipe; roll the pipe and weld up the pipe segments!!!
     
  11. jaguar

    jaguar Well-Known Member

    Man o man this new pipe is the bomb! The acceleration is surprising to say the least. So much so that it is causing my clutch to slip so I bought some cleaning spray for use on the pads. But I'm running 155psi (not advised unless you've changed all the bearings to higher quality ones), have transfer ports modified to direct charge flow to the rear so the increased suction wave from the pipe won't suck it out the exhaust port, have piston ramps, have a reed valve with Dellorto 14mm carb, and of course my CDI. Everything works in harmony together. Click onto my signature link to find out the details of all my mods.
     
  12. jaguar

    jaguar Well-Known Member

    A photo tutorial is now at http://www.dragonfly75.com/motorbike/makecone.html
    Those of you that want a torque pipe but know you are not adventurous enough to make one yourself should bug Sick Bike Parts to use these plans to make them available. I thought JNMotors wanted to make them so I made a pipe for them and mailed it to them. Never heard a word back. I know what happened. The owner is always so very busy and he probably didnt feel like he had the time to do it right by experimenting with different header lengths to find the perfect length. So now he has a torque pipe for people to look at and say "hey that is different". whoppee
     
  13. Fabian

    Fabian Well-Known Member

    That is an excellent photo tutorial.

    Now can you please make a photo tutorial that is 10,000 photos long and zip it together into a "video tutorial :cool:
     
  14. jaguar

    jaguar Well-Known Member

    I tried to make a video using a friends camera and it was a disaster. I know in the USA almost every one has a video camera nowadays but I have never owned one.
    Anyways there is nothing to see that your imagination can't show you. That's why smart parents don't let kids watch tv much so they have to use their imagination to invent ways to entertain themselves. Do you really need a video to show you how metal bends as you hold one side of it as it rests on a cylinder and you bang the other side with a rubber mallet? I don't want to be mean but anyone that needs that is kinda brain dead. No one showed me how to do it. I'm just a small town kid from Texas that don't quit till my goals are completed.

     
  15. Fabian

    Fabian Well-Known Member

    Jaguar, today everything is all about the 'visual' - besides, making a video adds a different dimension as you talk your way through things adding little bits of interesting information along the way.

    Although it might sound mean, inferring that i am brain dead, could it also be said that the same works in reverse when a person doesn't own a basic video camera or any basic (smart) mobile (cell) phone with a 5 (or more) megapixel camera that's capable of recording in 720p?

    It's plainly ridiculous to say that a video is not possible because of lack of knowledge to point and shoot with a phone or camera; resting on a surface to capture video footage...
     
  16. jaguar

    jaguar Well-Known Member

    I'm sorry but I just don't feel motivated.
    Owning smart equipment doesn't mean one is smart.
    I have made videos in the past so it's not that I'm not intelligent enough to do so. Just don't have much interest in doing so in this case.

     
  17. Fabian

    Fabian Well-Known Member

    But Mr Jaguar, please make it your public duty to grace us with a concise video tutorial on making a Torque Pipe - We all want to see your skills in action, as well as a few tips and tricks of the trade as flat sheet steel is turned into a work of art!

    To say that you're not motivated, in front of forum members is somewhat unbecoming of a person with your skills and talent, considering that you have designed, manufactured and are selling products to those who may require a motorized bicycle as reliable transport and to others who see it as an enjoyable hobby; wishing to try their hand at making improved accessory components.

    Please Mr Jaguar, can a youtube video be made showing your pipe making skills...
     
  18. jaguar

    jaguar Well-Known Member

    Here is an updated improved version for you to sink your teeth into. It gives even more torque than the previous one and lets you cut a section from the standard muffler to make the belly. And if you lessen the belly length from 100mm to 60mm you can raise the exhaust port to 24.9mm from the top of the cylinder (for a 162 degree duration) for 7000 rpm peak. If you have made piston ramps for the transfers then make the belly 80mm long. (click on my signature link to read more)
    48ccTpipe1.jpg
     
    Last edited: Jul 31, 2012
  19. Fabian

    Fabian Well-Known Member

    Are those pipe dimensions for a 66cc engine?
     
  20. jaguar

    jaguar Well-Known Member

    Yes it will work well with a 66cc engine, but the closer it is to port timing of 146/111 exhaust/transfers duration the better it will work. I have no Earthly idea what the port timing for your engine is but I can presume it is similar to the 48cc. I have asked before for people to measure their 66cc timing but no one responded which means either no one knows how to measure it or they are just too lazy to do so.
     
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