icedeocampo
Well-Known Member
accoding to BROWNI:
This is only a theoretical formula but you can use it for an estimate:
You can use this formula for the engine's maximal power revolution. In this revolution the gas speed must be 45-60 m/s. You can use the smaller value (45 m/s) if you want an engine with a good overreving characteristic, so you can rev up higher revolutions. You can use the 60 m/s if you want a very good engine at the "middle range".
carb diameter(mm)=square root[ (n * s * D^2)/(30 * v)]
n= maximal power revolution (1/min)
s=stoke (mm)
D=bore (mm)
v=gas speed (45-60 m/s)
The total area of the intake manifol must be 10-15% bigger than the carburator area! -> so if the carburator is 28 mm than the intake manifold is ~29,36-30,02 mm
I created a tool that computes that automatically:
(You need Microsoft .NET framework)
http://users.cjb.net/icedeocampo/
This is only a theoretical formula but you can use it for an estimate:
You can use this formula for the engine's maximal power revolution. In this revolution the gas speed must be 45-60 m/s. You can use the smaller value (45 m/s) if you want an engine with a good overreving characteristic, so you can rev up higher revolutions. You can use the 60 m/s if you want a very good engine at the "middle range".
carb diameter(mm)=square root[ (n * s * D^2)/(30 * v)]
n= maximal power revolution (1/min)
s=stoke (mm)
D=bore (mm)
v=gas speed (45-60 m/s)
The total area of the intake manifol must be 10-15% bigger than the carburator area! -> so if the carburator is 28 mm than the intake manifold is ~29,36-30,02 mm
I created a tool that computes that automatically:
(You need Microsoft .NET framework)
http://users.cjb.net/icedeocampo/
Last edited:
. Ofcourse the best way to know is by testing, but the outcomes are pretty accurate 
. Now I should have a 30mm carb according to version 3.0
