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talontsi92
04-08-2010, 02:54 PM
How to Build a Boost Leak Tester
(can also be used on N/A vehicles for finding intake leaks)

WHY DO I NEED ONE OF THESE?

Boost leaks are a common occurrence in turbocharged/supercharged vehicles with intercooler systems. In a mass airflow system such as the one present in a stock configuration DSM (Draw through MAF sensor before the turbo/supercharger) a boost leak can/will cause the vehicle to run in an overly-rich condition due to the air metered leaking out of the intake tract and never reaching the combustion chamber. These kinds of leaks can be difficult to detect without this kind of tester that you can use when the vehicle is not running.

Parts needed to make a tester for a stock frame turbo DSM (will vary by application):

• A 4 inch long piece of 2.5" inside diameter hose. (I used an old intercooler pipe coupler)
• 2.5” O.D. (outside diameter) PVC screw in adapter.
• 2.5" O.D. PVC screw in end cap.
• 2 clamps that will fit around the 2.5" pipe above. I like the quick release worm gear clamps for ease of use.
• Teflon Tape
• Drill with appropriately sized bit
• A valve stem (I used brass type you screw in)

Note: If you have a larger turbo/supercharger, the sizes of the end cap and hose will need to be larger in order to fit the inlet.

Assembly:

• Drill a hole in the PVC end cap that is just slightly smaller than the threads on the valve stem
• Wrap Teflon tape around the threads
• Screw into hole (a little pressure and it will cut its own threads if the hole is big enough; don’t over tighten, as it can easily strip.
• Cram (yes cram) the adapter into the hose. It will NOT want to go in, but persistence will get it in there.
• Place the first clamp on the hose, and tighten so that it grips the adapter
• Screw in the end cap with some Teflon tape on the threads to prevent leaks.
• Situate the second clamp near the opposite end of the hose

How to use the tester:

• Remove the intake and mass airflow sensor from the turbo/supercharger.
• Attach tester to inlet of turbo/supercharger.
• Attach air valve from compressor/air source to the valve stem.
• Block off any vacuum lines to a manual boost controller on a turbocharged application, otherwise it will bleed off pressure as you put it in.
• Pressurize the intake system to ~5psi MORE than the maximum boost pressure you plan to run, have a friend watch the boost gauge in the car. (just a little bit for N/A apps or you could blow the intake gasket if you put 20psi in it, depending on your application)
• Leaks are generally pretty obvious (they hiss pretty loud) but a soap/water solution could be sprayed on questionable areas and will bubble if there is a leak.

Places to look for leaks:

• Blow off/Bypass/Diverter valve flange
• Intake manifold Gasket
• Throttle Body gaskets
• Throttle Body Shaft seals
• Pinholes in the intercooler
• Pinholes in the intercooler piping
• Loose/Misaligned couplers
• Turbo outlet pipe gasket