Correct me if i'm wrong but the wastegate should stay closed while the boost is building and if you have your boost set at like 8psi. The motor doesnt see any of that boost until the 8psi is reach and once the set boost is reached the wg starts dumping right?

 

Most electronic / manual controllers keep the wastegate valve shut until you make full boost, then it lets the wastegate valve open up. Quicker turbo spool up.

 

hmmm my avcr does not seem to do that. From what i understand, if your wastegate is closed, i should not be able to be making say like 3 psi and hold it there on the freeway right? And I should only see a change in my boost gauge only when it hits 8 right? Mine just climbs up through the numbers and stops when i hit 8psi. This seems like such a simple concept, but it still confuses me.

 

No, you should be able to hold a steady boost level below your maxumum. The WG valve can open partially per boost pressure and remain in that position.

 

I thought that was the whole point of a boot controller. TO keep the wg closd until full boost for a faster spool up.

 

NO..

I think you have the wrong idea of the wastegate dump.. the wastegate dumps to atmosphere (or down your dump tube to the exhaust if you have it).

So your motor will see the boost raise from 0 to whatever you have set the controller to, but as soon as the controller sees 8lbs, or whatever you wanted, it'll let the pressure pass through the solenoid to the wastegate, at which time, the
wastegate pops open, and dumps the excess exhaust to atmosphere (or down dump tube).

 

Actually the WG is very similar to a bleeder valve. There is a spring inside of a housing that has a certain damping factor. As pressure builds in the exhaust system, it closes off the dump tube so that the exhaust can spin the turbine. Once a particular pressure has been acheived, the valve in the wastegate (that is held closed by the spring) begins to open as the spring cannot take any more exhaust pressure. It begins to bleed off exhaust from the turbo, preventing the turbo from producing more boost pressure. Once the desired pressure has been acheived, the WG valve passes any more exhaust pressure out of the system.

The MBC is an air pressure device that transmits pressure to the WG and if it is set to raise boost, it will provide some of the boost pressure read by the boost source to aid the spring in keeping the WG valve closed (it puts pressure on the valve from behind) Causing the valve to stay shut or partially closed to force more exhaust to spin the turbine... once the exhaust pressure surpasses the boost pressure keeping the valve closed, the exhaust will push it open and bleed off excess pressure.

HTH

<---- X2 who cracked open his WG the other day, just so he would know.