How do you check for boost leak? What methods do you use for detecting if there is boost leak present? What are some symptoms? Can someone just clear this up for me? thanks.

 

I think they can check for a boost leak when they put it on the dyno. The graph will show a big power lost. If you have a good tuner they should be able to narrow down the problem. I am sure there are other ways as well.

 

1) disconnect the tubing from the turbo outlet
2) disconnect the tubing from the throttle body
3) leave all other tubing connected including intercooler, etc
4) cap both open ends with some sort of custom plugs like the ones you can buy on ebay (or maybe you can make something from PCV tubing at Home Depot / Lowes)
5) pressurize the entire system with an air compressor to like 30 psi
6) watch the pressure gauge to see if it drops and listen for leaks

7) If it's leaking, start tightening clamps (within reason) and see if it stops
8) If it doesn't stop leaking, start looking for cuts, holes, leaks, etc by brushing / spraying a soap and water solution on all the tubing until you see bubbles forming on the leak.
9) If you find no leaks, then it's not leaking

 

You wouldn't disconnect the tubing at the turbo outlet or the throttle body, you just disconnect the inake portion of the turbo on the compressor housing and then connect a pvc pipe with a coupler and a nipple on it that connects to an air hose and then just pressurize the system. If you disconnected the coupler at the turbo outlet then the pressurized air would have no way of reaching the intercooler. I'm confused by your method, please elaborate as I'm sure we are probably doing this almost the same way but the wording is throwing me off.

 

You could do what you said also. It would even test the throttle body connection and the turbo. Your method would only need one plug as well. Just be carefull pumping up the rubber intake tube. It's doubtfull it will live under high pressure.

Throttle bodies don't normally seal 100% though, so you would need enough flow to overcome the pressure loss through the throttle body. However, so long as there was still pressure, you could watch the soap / water for bubbles with no problem.

What I posted is primarily for testing the intercooler and plumbing. It bypasses the turbo and throttle body. It puts the pressure source in one of the ends of the tubing, either the one removed from the TB or the one removed from the turbo.

 

Ah, gotcha. Yeah, with my method I don't use the rubber intake tube, I disconnect it altogether and use a pvc pipe with a coupler that attaches directly to the turbo. Because you're right, that rubber intake tube was meant for vacuum and not pressure. I like your method as well, but mine is a bit simpler and will allow the testing of all the hoses in the entire system like all the little vacuum lines on the intake manifold and so on.

However, I do understand what you are saying about the throttle body not sealing all the way and that potentially showing a leak that isn't really there. Then I guess the soap and water method will rule out the drop in pressure from coming from another spot. Although this is what we did on my friend's EVO 9 and it didn't seem to leak from the throttle body so I guess it can vary a little bit from car to car. No test is infallible I guess.

 

Thanks, thats a bit of work for boost leak check. Can the upper IC pipe cause boost leak?

 

Any hose that sees pressure can be a boost leak. This includes ic piping and couplers, vacuum lines on the intake manifold, vacuum lines runing from the turbo to the wastegate and solenoids, the list goes on and on. It really isn't that bad to test for this, but if you aren't feeling a power loss then you most likely don't have any leaks. Also, when you get the car tuned with ecutek or any reflash software of your choice then your tuner will be able to see if the wastegate duty cycles aren't producing the proper levels of boost for your car, which would be a tell tale sign of a boost leak.