How to Pressure Test Twin Turbo System?
 

I have lately been having trouble getting over 10psi boost on my twin turbos. I have been running about 13psi with PowerFC for about a year previously. So I saw Dale Clark's boost pressure tester and put together an equivalent tester. Here are a few questions I have about how to do the testing.

1) Can you test by just sealing the two intakes and pressurizing through one of them? Don't you have to also seal the output of the intercooler since the throttle butterfly valves probably don't seal that well.

2) Does the ignition have to be on or off? How can you make sure the turbo control valve is open?

3) Are the turbos supposed to be air tight enough to hold pressure?

4) When there are no leaks, should the system be able to hold pressure for a long time (minutes or more)?

5) There are alot of ways for air to escape the twins considering the pressure control and that there are at least four ports where vaccuum is taken for the control system. Do all the systems default to closed?


I have done the test as described on Dale's website, but I can't even get it to hold 1psi with my tiny air compressor. Do I have a major leak or is this test just supposed to help you find leaks by sound alone? Keep in mind the system will hold 10psi when running. If I do have a leak I'm never going to be able to hear it since the compressor runs the whole time.

Thanks!

1) Yes. Some air will pass though the engine, turning the e shaft a few degrees may help.

2)Off, the control valve will let plenty of pressure past for the test.

3) Idealy yes, but things like the shaft of the control valve will leak a little. Focus your attention to things you can fix like hoses, couplers, gaskets, ect..

4) No, quite a bit of air will pass though the engine.

5) doesn't matter for the test.

10 psi max but it does take a compressor of 1hp or so to provide the CFM needed. You may not be able to hear the leak/s. Just feel around with your hands.

Paul



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Looks like my compressor doesn't have enough capacity to do this test. Fortunately, I found a leak on the unused boost gauge port. I removed my boost gauge a while back and didn't get it closed off well enough. Thanks for the help!