Question on boost leak test and the evo8 and 1gen bov's.

[Flybiyou]

Me and my friend boost tested our cars we caped off the pipe that connets to the throttle body and put the tester on the turbo. Tested everthing at 25psi but when the pressure rasied past 10 to 13 psi our bovs would open I have a 1gen and he uses a evo8 bov. Should both of them open our should they stay closed under more psi. From what I have read the 1gen should hold 18 stock and crushed 25 mine is crushed. If it should hold more that could explain why I boost to 11psi instantly and 22 by 5600rpms. Slow for a s16g.

 

[EclipseTrbo420A]

The reason that is happening is because you cut of the pressure from the manifold and all its vac lines by capping it off. The vac line that runs from your BOV to a vac source from the intake mani is needed to hold the BOV closed under boost. You will have to re-connect your intercooler piping and then make sure everything is hooked up as if you were going to drive it away accept for the intake, instead put the tester on the compressure housing and pressurize the system. The pressure that builds in the piping and intake manifold will send pressure through your vac/boost lines and pressurize the chamber on top of your BOV's and keep them closed so you get an accurate reading. Good luck.

 

[Boosted98gsx]

The reason that is happening is because you cut of the pressure from the manifold and all its vac lines by capping it off. The vac line that runs from your BOV to a vac source from the intake mani is needed to hold the BOV closed under boost. You will have to re-connect your intercooler piping and then make sure everything is hooked up as if you were going to drive it away accept for the intake, instead put the tester on the compressure housing and pressurize the system. The pressure that builds in the piping and intake manifold will send pressure through your vac/boost lines and pressurize the chamber on top of your BOV's and keep them closed so you get an accurate reading. Good luck.

basically what this is saying is reconnect your IC piping to your TB and then boost leak test again. You need the pressure in the intake manifold to go to the BOV port as it helps keep the thing closed.

 

[Flybiyou]

I did the test both ways I have done many of them before I just decided to make it easy'er buy just testing the pipeing first which I found leaks I never knew of. Thanks for the info just wasent sure if they were to open or not.

 

[oldman]

EclipseTrbo420A is correct, you need the vac line to the top nipple of the BOV to keep it closed. If they are still leaking when the IC pipe is connected to the TB elbow, you can then conclude that the BOVs are in question.