Okay so I am at it again *^%%$#%@!!!! Second turbo still wont kick in....so I was under the car tightenning up lose exhaust bolts from the turbo ....(yeah I didnt see that coming) and I noticed as I was checkin all my actuators and vacuum lines that my turbo pre-control has ahole in the bottom of it...is that supposed to be there?

 

Depends on which side
If it is on the same side of the pipe where the hose goes in, then no
if it is on the opposite side, then yes, those actuators work on relative pressure, so it must be opened to air pressure
For "side" I mean those volumes divided by the diaphgram

 

All three exhaust valves run on both vacuum and boost pressure. NOT ambient pressure. I still don't know whether or not that hole should be there.

 

What kind of hole are we talking about? I can't see why/how it wouldnt' be there if it's not as designed. The PC and WG actuators run on pressure alone, only the TC actuator has both vacuum and pressure inputs.

Anyway, if this isn't resolved by tonight I'll check the junk turbos I have in my garage for you.

Dave

 

yes, it's supposed to be there. When the diaphram moves under pressure, the air on the other side of the diaphram needs somewhere to go. Hence, it goes out the hole.

 

TPC and WG are partially operated by the vacuum generated at the primary turbo inlet (where the stock boost pills are located).

 

alright....so the hole should be there.....And my second turbo still wont kick in for ****.

 

You're right - vacuum, not pressure. (Hey, actually vacuum is a pressure, it's just less than atmospheric)

Dave

 

IIRC, in the stock set-up, the hoses with the pills come off the Y-pipe (turbo output pressure). The other hoses on these actuators go to their respective solenoids which (duty-control) vent this pressure (unless they are plugged to use boost controllers) to the turbo inlet.

All of these hoses come off one side of the diaphragm in the actuator, so the other side of the diaphragm needs to be vented to atmosphere.

 

Grrr, I was right,... just all spun around today...

Since the springs in the actuators pull the rod in, and the nipples that go into the actuators are on the opposite side of the diaphragm, then it would require pressure to move them and vent the door. Reading through the description on the Vanditmars site agrees with it being pressure.

The hole is probably there to drain any water splashed into the opening where the rod comes out, or to vent air in/out that side of the diaphragm.

Dave