Celica ST205 3S GTE TVSV

[RobGT4Fun]

Does anyone have any pointers to control the stock wastegate with the stock T-VSV on this engine thru the G4X? Seems like im not getting much more than spring pressure. Trying to get to about 16psi in total. Any recommended wastegate duty cycles? The ecu is operting the T-VSV. 

[Adamw]

If DC is at 100% and boost is not increasing then it is either not capable of bleeding enough air or the exhaust manifold pressure is considerably higher than the spring pressure.

You can confirm which by temporarily removing the hose from the wastegate and carefully opening throttle to see if higher boost can be achieved with no boost reference.  Make sure boost cut is set to something safe when doing this.  

If you can get high boost this way then it is just the valve not flowing enough bleed, you may be able to fit a restrictor on the supply side.  

[koracing]

The factory TVSV for the wasteagte bleed off is not a good PWM-able solenoid from my understanding - though I've never actually tried and install MAC solenoids instead for boost control between the turbo and wastegate and block off the second port going to the TVSV.  If you want to verify function without the risk of massive overboosting (like disconnecting the wastegate hose) just set the output to "test ON" and go for a drive, then "test Off" and go for a drive.  if it doesn't change anything, then there's a problem in the wiring, or vacuum hose routing.  

It's also possible there is some other issue beyond the boost control with the mechanical VE of the motor (skipped tooth on the timing belt at the exhaust cam for example) that can limit boost pretty significantly.  Make sure your engine checks out mechanically.