The idle speed of a running compression should be between 50-75 PSI and that is about half of the static compression.
Explanation:
The Running or Dynamic compression is used to determine how well the cylinder in an engine is absorbing air, reserving it for the proper length of time, and releasing it to the exhaust. The static or cranking compression test is used to check the sealing of the cylinder. Before performing the running compression test, the static compression test is first performed to rule out other issues like bent valves.
The standard value for the static compression is given by;
Compression ratio * 14.7 = Manufacturers Specification
The running compression should always be half of the static compression.
The stress due to a pulling force is obtained dividing the pulling force by the the area of the cross section of the rod. The respective area for a cylinder is:
