Originally Posted by
John_M_
Here's the formula from Walbro's service manual.
D = K x Square Root(C x n)
where:
D=venturi diameter, in millimeters
K= constant between 0.65 and 0.90 (determines the smaller and the biggest diameter to be tested at the specific engine)
C=cylinder displacement, in cubic centimeters
n=RPM at peak power/1.000
ran the numbers in the equation John provided and here are the results - I think "n" has to be RPM/1000 to work.
given a 7mm bore that I'm using, the K factor comes out to 0.74 which is mid range.(at 12,000 rpm)
the 7mm bore shows a rpm range of 8,000 to 15,400 given the K factor range provided....
As planned I'm going to prop down to see what effect that has...