make your own torque pipe

[Deleted member 12676]

If you download my latest version of Excel file for calculating pipe dimensions you will have a slightly better calculation of stinger size and length.
Running the stinger alongside the pipe makes it hard to calculate what equivalent pipette size it is. the diifference in low end torque between the two designs is very small. I am making all mine now with internal stinger.

 

[SuperDave]

I'd imagine that running an internal stinger(made out of pipe) would be easier to attach a tailpipe or muffler as opposed to a sheetmetal belly stinger.

Hey Jag, I had a thought I wanted to share with you: If you cut lengthwise wedges into the tip of the internal stinger pipe, you could bend it & shape it into a point, which would have an aerodynamic benefit of making the pressure wave flow over & past it with minimal restriction. If the stinger end is blunt, rounded or flat it might deflect a portion of the pressure wave and effect the return resonance wave, reducing power.

I noticed your "Torque Pipe" design has 2 convergence cones with a spacer in between. When calculating header pipe length, where do I measure from, the lead edge of the 1st convergence cone, the 2nd, or split the difference from the beginning of the 1st and the back tail end?

And thank you for including the measurements for a 66cc(for those of you not paying attention, that's the 'box' in the lower right side of the torque pipe pics). If I built a pipe for a 48 to go on my 66, I might end up "short changing" myself! Which pipe configuration would you recommend for maximum performance? The 1st design you posted(page 1, post#1 of this thread) or the 2nd(page 2, post#18)? Mind you my bike is a single speed(like most of us), so I/we would want one with a broad power band, not a peeky one that only supports a narrow powerband enhancement.

 

[Deleted member 12676]

yeah that is a good idea for not wasting any of the pressure wave.
for header length as revealed in my EXcel file it is from piston to beginning of diffuser. From piston to beginning of header is 35mm.
the 2nd design is better.

 

[fx-2]

I got it running last night , just a quick run down the block . Will post some more picture went I get time . You ask about the mods here the cylinder port work . Dan

 

[fx-2]

Finished Bike

Here are the pictures of the finished bike and a race bike with a torque pipe on it .

 

[Deleted member 12676]

I dont see a stinger on your torque pipe (on the black engine).
Is it a stinger channel running along the bottom of the pipe?
How does it run with the pipe?

 

[fx-2]

Stinger

Both pipes use belly stingers , on the blue bike the stinger goes down in front of the tire . On the race bike it goes to the side . Have not had time to ride my bike . I move from SOCAL to Tucson on the first of May . Lots of things to do . Will update when I start riding it . Dan

 

[bahramu]

How do you guys go about constructing the exhaust header (pipe that runs from cylinder to the beginning of the first cone of torque pipe)?

I don't have many tools, but I can probably borrow whatever I need. I'll cut off the muffler from my existing stock exhaust and use that as the first bend but what's your method of extending the header and completing the curve to finish redirecting it towards the rear of the bike? I've seen some people filling pipe(I'd use copper I think) with sand/packing in/filling/packing/capping and then bending to desired curve and welding that to complete the "U" curve. I also looked for pre-bent pipes that I can buy to save time but haven't seen anything. Is there a thread about this already? Can't find it. And great work! Thanks!

 

[bahramu]

Oh, I just remembered Bobo used auto silicon hose as a temporary header extension. Can this be used "permanently"? Are there any disadvantages to using silicone hose as a header extension as opposed to metal?

 

[HeadSmess]

silicone isnt petrol proof for extended periods, and doesnt appreciate being heated over 350 degrees celcius usually. also too flexible.

its fine on nitro engines cus they run cooler, and is usually used in short lengths were it isnt actually exposed to exhaust gas.

dunno bout these guys, but for the cones, i now have a sheet roller and a tapered mandrel. later ill make these match the actual taper im making.

bending pipe, light a fire! get it red hot and it bends like play-doh. otherwise... cut through pipe at angle. turn 180, cut at same angle, halfway through, so you get a small crescent of pipe. close pipe where section came from for inside the bend, weld section in gap left on outside of bend.


hint. use thin copper pipe, thick wire, anything that will bend and hold its shape to lay out the curves onto the frame. break any cone sections down into 1mm rises per "whatever length the taper needs", and use these lengths to work out angles and positions of bends. make some "washers" as wide in diameter as critical parts of pipe. place on jig wire where appropriate, to work out clearance around things.


dont try making a pipe out of copper! 1, it work hardens and goes brittle. two, it goes all soft and gooey when heated and cooled(annealing) and 3, its really hard to join copper effectively. copper welding is hard, brazing is so close to welding that it is welding, silver solder holds but needs really good joint designs to be strong, especially when its hot. and soft solder, thats just going to melt.

oh, and that green oxide stuff on copper? the "verdigris"? highly toxic and poisonous unlike good old ferrous oxide or RUST

if you arent up to the joining, find a welder. the metal fabrication part is basically simple, and if you manage that, at least the welding will be fairly reasonable.


use 0.8 to 1mm. thinner, too hard to weld. thicker, too hard to bend!