Normal Air-pressure-loss rate for Pressure Testing

[vavJETTAw36]

Does anyone know what an acceptable rate of loss is? I recently fixed a check valve leak and was ecstatic about 28 second 15-0psi rate. Is this acceptable?

Fuel trims for a 10 mile trafficy commute (car is e85 Stage 3):

B1S1 idle 6.8%
B1S1 part -8.6%
B2S1 idle 6.4%
B2S1 part -10.9%

[vavJETTAw36]

Anyone?


Sent from my iPhone using Tapatalk

[julex]

It literally depends at what particular cycle the pistons stop at during the leak test. In some spots of 720deg crank cycle you will have more intake valves open than the other so your pressure loss will vary depending where you land with that. Then you might have a more leaky piston seals on some engine when pistons are not compressing, again making it all variable.

Anyhow, how long it take to go to 0psi is completely irrelevant as given that you clog all the external leaks, you're only then testing some irrelevant aggregated leakiness of engine for which you should really use a leak down test if you're interested in health of cylinders.

[vavJETTAw36]

It literally depends at what particular cycle the pistons stop at during the leak test. In some spots of 720deg crank cycle you will have more intake valves open than the other so your pressure loss will vary depending where you land with that. Then you might have a more leaky piston seals on some engine when pistons are not compressing, again making it all variable.

Anyhow, how long it take to go to 0psi is completely irrelevant as given that you clog all the external leaks, you're only then testing some irrelevant aggregated leakiness of engine for which you should really use a leak down test if you're interested in health of cylinders.

Makes sense! Thanks for the detail. So really if you don't hear or see leaks you are good to go (from an external leak perspective).

Thanks Julex


Sent from my iPhone using Tapatalk