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OMG... Simple Fix to Boost Creep Problem


sims76

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I have been running 12 PSI with spikes to 14. I have been unable to get boost below 12.

 

I remounted my wastegate actuator and have been preparing to pressure test the actuator and port the w/g hole in the turbine housing and add a bigger flapper, etc..

 

Solution: I have my w/g signal line and my BOV signal line teed off the same port on the intake manifold. I never thought to remove the BOV signal line as a test. I did that today at lunch and the boost held to about 8PSI. PERFECT!

I can't believe I didn't think of this sooner. :twak: This tells me that the BOV signal line may bleed off some pressure causing my w/g actuator to see a lower pressure than the intake manifold itself, therefore allowing a higher pressure in the manifold.

 

Argh...

 

****** EDIT ******

I spoke too soon. Now that I have reconnected the BOV with it's own dedicated line and manifold and done the same to the w/g actuator hose, I'm back to 12PSI. The only change since before was that I reconnected the BOV. I'm stumped, how can this raise boost?

 

****** SECOND EDIT *****

To answer my own question, running with the BOV port vented to atmosphere can cause the BOV to leak because it doesn't have the extra pressure holding it closed under boost. It was basically acting like a stock pop off valve.

 

Finally decided to pressure test the actuator and found that it doesn't open until 12PSI. I was under the impression that it was a 7PSI actuator.

 

Conclusion: The w/g actuator is working as designed by opening at 12PSI. So I went ahead and ordered the 7.5 PSI Dual Port Turbonetics unit from http://www.jegs.com

 

I apologise for the excessive editing, but this info may help someone else someday...

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Yo Vinh,

 

I'm actually out here in the King of Prussia area. I would like to come down to South Philly sometime to check out your Z's. I appreciate your great attention to detail, because that is something I need to work on.

 

Think back about 16 months ago....we spoke on the phone a few times about a turbo motor your friend was selling. Obviously I did end up with a turbo setup, I hope you did eventually sell yours for a decent price. I've also seen your "Bruce Lee" Z in Chinatown a few times. I have many asian co-workers and they have me hooked on the good food down there.

 

My email is mls228 "AT" gmail.com

I'll send you my phone number also.

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Yes please send me your numbers. My brother who helped me a lot with my Zs lives in Norristown with my mom. Frequently on weekends I go back to Norristown to visit my mom. I will call you and check your schedule so I can stop by to check out your Z.

 

I still have that 81 280ZXT in my garage lol .. I don't want to sell it just yet. Yes give me a call if you come down to S. Philly or even Chinatown. It's not far from me. I usually take my new toy to South Street for show off. Bring your Z down and we go together and stop there for coffee or something. Talk to you later.

V.

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