|
|
|
The probes were made from 3/32 inch OD thin wall brass tubing. The pressure sensing holes were opened with a #60 drill. The end of the probes were closed with JB Weld. The tubes were bent so that one sensing hole faced up stream and the second bent to face downstream.
If one calculates the flow velocity passing by the probes using the engine displacement and the carburetor throat cross sectional area, the pressure difference between these probes will be roughly, 1.5, 2.4, and 3.4 inches of water at 4,000, 5,000, and 6,000 rpm respectively. A bracket to support the hose end of the tubes was made from 0.020 inch thick aluminum. |
This view shows the parts in place without any bonding by JB Weld.
The carburetor wall thickness was quite thin and so it was necessary to use longer tubes with outboard support. 3/32 inch ID holes were drilled through and followed by a larger drill to chamfer the hole and give a better adhesive bonding surface. |
JB Weld was used to fix the probes into place.
|