Bump.
Any more thoughts on this?
I got ~1% leakdown on a 912 engine I am messing with. Too good to be true?
Per wikipedia:
Leak-down tester - Wikipedia, the free encyclopedia
Some manufacturers use only a single gauge. In these instruments, the orifice inlet pressure is maintained automatically by the pressure regulator. A single gauge works well as long as leakage flow is much less than regulator flow. Any error in the input pressure will produce a corresponding error in the reading. As a single gauge instrument approaches 100% leakage, the leakage scale error reaches maximum. This may or may not induce significant error, depending on regulator flow and orifice flow.
At low and modest leakage percentages, there is little or no difference between single and dual gauges.