fabrication of tuned pipe

I am looking to increase the power/top speed of my '79 honda express and I want to fabricate my own tuned pipe. Being a welder and a machinist, contstructing the pipe wouldnt be the problem but I am not sure of the dimensions. does anyone know of a book/program/referance containing pertinant equations? thanks for your help


RE: fabrication of tuned pipe

You maybe a little over your hear on this one. Tuned pipes require absolutely presice timeing of when negitive and positive pressures waves are sent back to the cylinder to be truly tuned. These pressure waves either suck out more exaust gasses alowing more charge (air/gas mix) to enter the cylinder or push the charge back in. Due to different shapes of pistons, the way charge enters the chamber is different for all engines so I would find it hard to belive that any formulas or programs are out there. Your best bet is to look at other tuned pipes also take a look at www.howstuffworks.com, they can explane the principles at play and give you a good place to start. Make pipe, see how it works, then just play with different body, stinger, etc. lengths. Your end product may not quite what you want it to be but if done right it will be better than stock. (sorry about the spelling),.

Good luck, I'm interested in the end results


A smokin pipe

There are formula's available for pipes.. in books and on the net.

The problem with these formulas is that they are generally made for high performance racing engines.. which mopeds are not.

There are also software programs you can buy to have a computer do all the figuring after you input your engines variables.

I have calculated and built my own pipes twice.. and have measured several tuned pipes made by commercial performance companies to see how they compare to book formulas.

One thing you might consider is to copy a BiTurbo.

On the MacDizzy site.. go to 'Engine Building Formulas' for a basic pipe calc formulaI

RE: A smokin pipe

here's MacDizzy........ http://www.macdizzy.com/2stroke.htm

RE: A smokin pipe

And this site has a few tech articles on 2-strokes and pipes....


And I would say the best book is Gordon Jennings "Two Stroke Tuners Handbook"

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