custom exhaust program

[kfx450]

I was playing around on the computer tonight and found a custom exhaust program for 2 strokes. Mainly geared towards carts but will work with any 2 stroke engine on expansion chamber size and length. I have found some very strange sizing for a 50cc engine and was wondering if people could give me some accurate numbers. So that I can give out the results just as a base line. I know most people won't make there own custom pipe but it is neet to see the numbers. I know most of the numbers for a 50 but could use better numbers for the Port Opening Deg. This program has other options like Diffuser styles and Fuel types. I was using gas and 3 stage diffuser. you can also change the width of the power band for different pipe length numbers.

Here is what I need.

#of cylinders
Bore mm
Stroke mm

Ex open period Deg
Main Transfer Open Period Deg
Sec Trans Open Period Deg
Rear Boost port Open Period Deg

Target HP
Target RPM@ Peak HP
Ex Port Exit Diameter mm
Ex Port +Exh Gasket Length mm


Will plug in your info and print out a Diagram to show.

thank you
jayme

[hotquads1]

sounds like you have run across the old 2-stroke Wizard program, you will be able to compare different scenarios and look at pipe changes , but I remeber that program had a glitch or 2 in it so it will take some experimenting to get the best results. Have fun and good luck. If you are lookinf for some #'s to punch in on a 50 cylinder , try this 175 ex and 142 transfers, this is the oem DRR cylinder (although I have found them to vary from cylinder to cylinder)
Marc

[kfx450]

you are correct it is the 2 strock wizard. The numbers it gives for 50's are interesting. They show the expansion chamber only having a 2in Diameter. the numbers for the 90 exhaust seem to be pretty close.