I performed a boost leak test on my Sky recently. Figured I would share the procedure. It's pretty easy and the parts cost less than 5 dollars for the DIY version. You can buy a test cap which shabby recommended for about $25 from here
http://www.boostpro.net/prodtester.html and skip half of this.
I just did a test of the charge system right after the turbo. It's easier because you don't have to plug the lines from the turbo. Most likely you don't have a leak from your turbo. If anyone has done that method, please append this guide.
Stuff you need:
1) Tire Valve: There seem to be two common sizes, one that requires a .453" hole and one that requires a .625" hole. I bought the smaller one.
2) Drill bit for the valve. This was tough. I didn't wanna go too big, but I think most guys just use a 1/2" drillbit and it works fine. Technically .453" is about 11.5mm and a little bigger than 7/16" I used a 7/16" bit and had to make the hole bigger. A 1/2" hole is probably fine.
3) 2" PVC threaded plug or something else stiff that will plug a 2" hose
4) Tape: air would leak out of the threads of the PVC plug so I put teflon tape, but I'm sure duct tape would work.
5) 11mm deep socket to loosen the Tbolts
6) Compressor or tank of air
7) Spray bottle of soapy water
Process is pretty easy.
Drill the hole in the cap wherever you want, pop the valve stem into the cap. Make sure it's nice and tight. If you are really slick, you can tap a pressure gauge into the cap as well.
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Loosen off the T-bolts from the hose coming off the turbo with your 11mm deep socket. Socket adaptor for electric drill optional, but makes it fast! Never use the drill to finish off tightening these. You don't wanna overdo it.
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Take the turbo side of the rubber hose off the pipe and twist the hose so the pipe isn't in the way.
Put tape around the PVC cap threads to keep air from leaking through the threads. It happened to me the first time.
Stick the cap into the hose, push it in about 1/4" then tighten the T Bolt clamp onto it. Tighten the other Tbolt clamp onto the charge pipe.
This is what it should look like in the end:
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So by being a cheapskate, you have no way to read the amount of boost you're going to put into the system. You have a few options. Fill up the air then use a tire pressure gauge to check. Have a friend sit in the car with the key on but engine off and watch the boost gauge.
I decided to go with another option, and hookup my HP Tuners with laptop and start logging and view the boost rising on the computer screen.
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Once everything is set, start pushing some air into the system. Then listen for leaks. Spray joints that are likely to leak with the soapy water and watch for bubbles. The boost pressure will drop off since the air will leak through the throttle body and whatever valves are open when the engine last stopped.
I pushed my car up just under 30psi with no leaks. I have T Bolts on the intake elbow but nothing else, and it held fine. You probably don't have to push that hard to find leaks. Most people do around 20psi.
That's it!
References:
http://www.youtube.com/watch?v=u3Kqh52PC6Qhttp://www.youtube.com/watch?v=fdjadhUP1u4