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how to make a boost leak tester!

i looked on the vfaq but i was wondering if anybody has used something better and what do i need to make it thankyou


Well-known member
Jun 27, 2002
Park City, UT USA
Assuming a 14b turbo, a 2" hardware store rubber coupler(with worm clamps), and a 2" PVC cap, a 16G has a tad larger opening, but small enough to squeeze a 2" coupler. Either buy a cap with a 3/8" threaded hole and put a quick connect NPT air fitting(threads are compatible) or just a tire cap fitting by pre-drilling a hole. Essentially you just want to put a cap over the turbo inlet and seal it. Then using compressed air, pressurize no more than 20 to 25 psi(no more than slightly higher than you would under boost) and check for escaping air. I recommend you rotate your engine to TDC to close your valves.

You will likely hear either a little bit or a lot of air escaping. Track down the source or sources by sound, feel, or soap bubbles. Take one leak at a time from easiest or largest. Come research whenever you think you found one that might require a complex part to be disassembled. Some leaks are easy to fix, some are not worth the effort if they are small leaks. Some air will escape. A turbo is not perfectly sealed. You want to get the most obvious. Keep the leaks far under the ability of the air to compress while in boost. The ECU will be able to perform better because the volume of metered air in the system remains the same. If your engine is erratic or lacking in power that is one of the first things you should check.

Related question-
If on any cylinder an intake and exhaust valve are both even slightly open wouldn't air escape thru there?

If so can you set your crank to a point where you know they are all closed?

Does it matter?


Well-known member
Jan 10, 2005
Top Dead Center.


Staff member
Aug 8, 2004
KC, Missouri
Rotate the crank pulley until the white cam marks line up parallel with the top of the head. Look up timing belt changing on VFAQ and it should show a pic.

Sweet jeezus! 21 freakin' dollars? /ubbthreads/images/graemlins/ooo.gif That's quite the tidy profit! I'll stick to Home Depot Racing and avoid MockV.


Well-known member
Dec 25, 2003
Key West
time or $ ? And how much do you actually save? I made mine for $5, but I have the creativity of the ages. I also have a friend make one out of a coffee cup (not a typo) and we use it frequently.
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