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Discussion Starter #1
My gen3 swap is in and running great, and now I even have a working speedometer! My last problem is that it won't boost over 7 psi, which is the mr2's safe mode. I don't understand why though. The ambient temperature is 50 degrees, the car is fully warmed up, and I'm not showing the check engine light. I'm going to disable my T-VSV today and see if it is indeed in safe mode. If the boost doesn't rise after disabling it, I know that everything is fine, I just need my mbc on there. Why would it be in safe mode?
 

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Discussion Starter #5
Mine, for whatever reason, ended up boosting 8 from factory. MBC install fixed that and now I'm boosting 15 psi.
 

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Add me to the list. 7psi without boost controller, and 16 is the max I can get with the boost controller all the way closed.
 

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The OEM boost spec is 7.1 to 11.8. It is not unusual for some cars to run near the low end of the spec. But a $50 boost controller almost always fixes it.

I suggest you install an indicator light to monitor the T/VSV operation, then go from there. Most likely, the ECU is enabling high boost, but other variables are keeping you at the low end.

If however you find that the T/VSV is NOT enabling high boost, then you need to check the related input sensors.

bill
 

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Bill, I believe all of us here are referring to our ct20b's and on many of these on gen3 motors. I have two mr2's right now, both have gen3 motors. One runs 14psi without any boost controller at all and the other runs 7 without a boost controller. Remember, gen3's came stock running 13psi, not 7.1-11.8 although I still understand that can be lowered depending on TVSV engagement.
 

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But regardless of what turbo you are running, it is the boost control system that determines boost levels. Specifically, the actual spring tension of the actuator spring, and actual orifice size in the T/VSV determine operating boost limits.

bill
 

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My car is just a pretty factory 91. I have a boost controller and I disabled the tvsv. Still can't boost past 6psi. So these 'input sensors' you talk of have to be the problem. Is there a list of sensors that I need to check before throwing my car in the trash can? Thanks for the help.

Sean
 

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Just going to mark this thread. At the moment the speedo isn't working, so my car is in safe mode. But safe mode regardless of working speedo? Interesting...
 
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