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Hi ,
If u think there is some science in the exhaust system the inlet manifold is as least double the info
To keep it simple I wll not bang on about the formulas for flow with ,without fuel , fuel/air distribution ,reversion back to carbrettor blah blah blah u get the idea !!!
Basically everything has a function from the air filter and or cold air induction all the way thru to the inlet valve including the combustion chamber shape volume etc
Only the basics go with an inlet valve size and stick with it
shape the combustion chamber to suit
Flow test the heads at different lifts ,port to suit flow requirements
swirl polish valve
top cut and back cut valves for better flow
Fix the short side radius generally a hump of weld [to improve flow ]
air flow at 90 degrees is a killer for airflow
I am only concerned with matching of the main components
There are plenty of other things to do but I am just going basic
Make inlet manifold to approx. 80 %to 90% of cross sectional area compared to the inlet valve size
Carby throat 90 to 100% of valve head
As with all things this is only approx. but at least a good starting point
formula single port and carby
rpm x engine cc x volumetric effi divide 3330then find the square root
eg 3600x.625cc x.95v/e divide by 3330then sq root
=.801 inches diameter x 25.4 = 20.35mm dia
cheers tomo
If u think there is some science in the exhaust system the inlet manifold is as least double the info
To keep it simple I wll not bang on about the formulas for flow with ,without fuel , fuel/air distribution ,reversion back to carbrettor blah blah blah u get the idea !!!
Basically everything has a function from the air filter and or cold air induction all the way thru to the inlet valve including the combustion chamber shape volume etc
Only the basics go with an inlet valve size and stick with it
shape the combustion chamber to suit
Flow test the heads at different lifts ,port to suit flow requirements
swirl polish valve
top cut and back cut valves for better flow
Fix the short side radius generally a hump of weld [to improve flow ]
air flow at 90 degrees is a killer for airflow
I am only concerned with matching of the main components
There are plenty of other things to do but I am just going basic
Make inlet manifold to approx. 80 %to 90% of cross sectional area compared to the inlet valve size
Carby throat 90 to 100% of valve head
As with all things this is only approx. but at least a good starting point
formula single port and carby
rpm x engine cc x volumetric effi divide 3330then find the square root
eg 3600x.625cc x.95v/e divide by 3330then sq root
=.801 inches diameter x 25.4 = 20.35mm dia
cheers tomo