Wastegate...???

[Tx_Allstar]

I am new to my svo. My Turbo doesnt build the way it should is what everyone tells me that rides with me. I have seen people talk about the wastegate. What is it? Where is it? What do i need to check on it? Thanks for any help in advance,
A.J.

[jayG]

Whats your max boost? The wastegate is part of the turbo assembly and is opened and closed by the actuator which is probably were the problem is. If the actuator opens too soon there will be less boost maintaned. The actuator maybe mounted in the wrong position on the compressor housing which will cause it to open too soon.

[Tx_Allstar]

I will have to check but i know it doesnt go as high as it should in premium mode. I think it only goes to 12 or something like that.

[GAboySVO]

AJ,

On the 85, if still in stock trim, the turbo would build 14 psi in premium mode. The wastegate acts as a "safety pressure relief valve" in that the turbine can spin the compressor wheel enough to blow a hole in the engine or piston if detonation occurs.

The wastegate actuator is set up to build ~9 to 10 psi before the boost pressure overcomes the wastegate spring force. There is a Boost Control Solenoid (BCS) on the front of the right front shock tower. The BCS bleeds off pressure away from the wastegate (controlled leaking) so that it doesn't open until more pressure is generated.

You can test the wastgate using ~10 psi of compressed air applied to the wastegate actuator to open. Once you have verified that the actuator is functioning properly, then you can gradually apply air pressure to the actuator to see what pressure causes the wastegate to move. The spring can weaken from heat over time.

Check all of the vacuum lines between the turbo, the BCS, and the wastegate. Also verify that your premium switch is functioning. They have been known to fail. You can use the fog light switch for a test by swapping the wires.

Find out what your max boost is "regular mode" and compare that to the "premium mode".

[SVOeric]

just a note -- you could be making 14 psi of boost, (or 10 # for that matter)

the stock gauges are known to be very inaccurate.

when you flip the premumum switch, do you get more boost?