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i need to know how psi (pressure when testing) affects the results. I have read many instrustions suggesting testing begin at 80psi to 90psi, and even 100psi.

If the test is run at say 45psi and shows 55% leakdown, could that mean that the psi on the tank was 90psi and 55% was lost in leak down, or that the tank was at 45psi and the guage saw 55% of that lost?

If its the latter case, would upping the pressure cause more or less loss (cause the rings to seal better, or just blow more by b.c there is more pressure).

Thanks, any advice would help.
 

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I never paid as much attention to the pressure, as to the leak percentage. That tells you, out of how much air you're putting into the cylinder, how much is escaping. 0% leakage would show up as the same amount of PSI in the cylinder as the air source. I think normal leakdown is 8-12% roughly.
 
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