TVSV
From Celica GT-Four / Alltrac - ST165 ST185 and ST205
Available Unit IDs: C01, C02, C03, C04, C05, C06, C07, S01, S02, V01, V02, V03.
Example: <google uid="C01"></google>, <google uid="C01" position="left" ></google>
Turbo Vacuum Switching Valve
An electronically controlled vacuum switching valve. Controls boost by bleeding air from the actuator. The amount of boost increase given by the TVSV is determined by the pressure drop across the valve - the size of the ports are what determine this. In standard form they give you an extra ~3-4 psi. These can be bored out - for example boring them out to 4.8mm gives almost 14psi increase (measured)! (Not advisable). This solenoid valve can be used in conjunction with the megasquirt ECU to control boost, but will require boring out carefully to allow more than the stock maximum boost to be achieved.
In the picture below ("TVSV Port on Actuator") the TVSV is connected to the "B1" connection labeled. In order to disable the TVSV you should find this connection (remove the intercooler first for ease). It has a short rubber hose linking it to a hard pipe on the side of the head. This rubber pipe should be removed and the two open connections should be blocked. I will organise some more photos ASAP. Ignore A1 and A2 - these are linked by a short hose and are required at all times, these ports are where an external boost controller will be connected to, to raise boost.
The TVIS and TVSV can be accessed from the drivers (right, in the UK) wheel well - remove the wheel and go in through the steering rod hole. From there you'll see and sight somewhat like those below but you wont have the luxury of having the engine out of the car, unless you're as unlucky as me!
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