Exhaust/expansion chamber calculator - need engine info

Nov 27, 2013
143
4
18
earth
www.Frankenbikes.com
I am playing with this expansion chamber calculator - but i need infrormation about the china girl engine.

I don't feel like taking apart my bike since it is working right now, and at least one piece of info I have no idea how to get or really what it is... but someone i bet here prolly knows this info or where/how to get it.
(i am looking at you Bairdco)

I need:
exhaust duration
exhaust port width
exhaust port height
jug wall thickness at the port

coefficient (what is that even?)

I just want play around with potential configurations, compare existing products to it or maybe make a thing

BTW this a free app on google play, i am running it on my phone

Thanx!
el
 
Nov 27, 2013
143
4
18
earth
www.Frankenbikes.com
Okay, so I think I am down to just needing to figure out the exhaust duration

coefficient is, according to the app instructions, the "width" of the effect across various RPM - with .1 being narrow and 2.0 being broad

this calculator seems to create really long expansion tubes, if 1,000 mm = ~39 in, but it may be my duration number


I will follow up

el