Leak down test

[paulmac]

Hi can anyone confirm that my dumpvalve shouldnt be opening under 1 bar pressure, done a leak down test and once i apply 1 bar or more dumpvalve opens, its a turbosmart and dumps to air, should it not open with vacum, fitted to aan engine, many thanks paul.

[AndyP]

Do you mean a leak down test or a boost leak test? If a leak down test is making your dump valve open you've got serious problems

[paulmac]

My mistake boost leak test, thanks

[AndyP]

OK, that makes more sense! How are you testing it? Normally, because the dump valve is a recirc it won't make any difference if it opens.

You also have to bear in mind that in normal operation the DV has boost pressure applied to the top of the piston to help the spring hold it shut.

[paulmac]

dump valve vents to air ,not a recirculating valve, pipe s blocked off be 4 throttle body and pressure applied after turbo with any take off hoses blocked, so would this b normal under these tests for the valve to open when 1 bar is reached

[AndyP]

I would have thought it was normal because you don't have the boost pressure applied to it to help it seal. The only way to be sure would be to have a 2nd compressor putting pressure on top of the DV, not sure how practical that would be though!

[paulmac]

Cheers for help