stock 3sgte boost psi ????? Options

[toyotacrazy]

I just got my swap done and drove it today. Its only boosting to 6-7 max psi. I think the mechanical boost gauge is ok because its vacuum is reading 20 at idle. When I pinch off the vacuum hose on the side of the turbo the boost goes through the roof until fuel cut! Is this normal for a stock 1991 st185 with top mount intercooler to only get 6-7 psi? I thought it should be about 10-12 psi. Or is that psi only possible with modifications to the wastegate? Thanks for the help!

-toyotacrazy

[toyotacrazy]

I understand how the tmic is not the best setup. I am working on a fmic now. But could it really be holding back that much boost? I mean...theres st185 celicas running around with tmic pushing 16 psi of boost. I know they have the factory hood scoop though. Ill try the fmic and see what happens. Thanks.
-toyotacrazy

[Gary]

I understand how the tmic is not the best setup. I am working on a fmic now. But could it really be holding back that much boost? I mean...theres st185 celicas running around with tmic pushing 16 psi of boost. I know they have the factory hood scoop though. Ill try the fmic and see what happens. Thanks.
-toyotacrazy

A/A TMIC will not function without hood scoop.
You need airflow too cool down the IC. That is why they call it " ait-to-air intercooler"
With out scoop to feed air to it, I would call it "interheater"
Because of this setup, you are pumping hot air into the engine.
And that is the reason why the ECU won't let you boost more.

The ECU does this via the T-VSV (Turbo Pressure Vacuum Switching Valve).
Basically it is the factory boost controller.
It is just an electronically controlled bleed valve.
It regulates boost by bleeding air out of the wastegate actuator to allows more boost.
The ECU switches it on and off base on feedbacks from many sensors. (temperature, knock, etc..)

This post has been edited by Gary: Jan 2, 2007 - 8:53 AM

[zCelicaDude]

I understand how the tmic is not the best setup. I am working on a fmic now. But could it really be holding back that much boost? I mean...theres st185 celicas running around with tmic pushing 16 psi of boost. I know they have the factory hood scoop though. Ill try the fmic and see what happens. Thanks.
-toyotacrazy

A/A TMIC will not function without hood scoop.
You need airflow too cool down the IC. That is why they call it " ait-to-air intercooler"
With out scoop to feed air to it, I would call it "interheater"
Because of this setup, you are pumping hot air into the engine.
And that is the reason why the ECU won't let you boost more.

The ECU does this via the T-VSV (Turbo Pressure Vacuum Switching Valve).
Basically it is the factory boost controller.
It is just an electronically controlled bleed valve.
It regulates boost by bleeding air out of the wastegate actuator to allows more boost.
The ECU switches it on and off base on feedbacks from many sensors. (temperature, knock, etc..)

thats interesting above ^^

is this T-VSV the same on the ST205?