Wastegate actuator question

[Mid_Life_Crisis]

I`ve been trying to better understand our turbocharger and its control system. So far I`ve learned some interesting things and some that seem a little odd.
I need to make sure I understand the wastegate actuator correctly. Mostly, is it true that the actuator is actually holding the wastegate closed under normal conditions and when exhaust gas needs to be vented it allows the exhaust pressure to force the wastegate open? As opposed to the actuator opens the wastegate, which would otherwise be closed.
In other words, if you removed the actuator, the wastegate would be held open by the exhaust gasses and you would build no boost, as opposed to the gate just staying closed and the pressure never venting.

 

[Mid_Life_Crisis]

Okay, so is this question too stupid to be answered or does nobody else know either?

 

[matsuda]

The wastegate is normally closed unless opened by (boost) pressure.
The actuator has a spring that normally keeps the wastegate closed.

 

[BillTheCat]

The wastegate is normally closed unless opened by (boost) pressure.
The actuator has a spring that normally keeps the wastegate closed.

I'm not sure what kinds of safeguards Mazda has in place on our turbo setup, but in many cases if you remove the wastegate actuator, you're opening yourself up to a turbo upgrade. After you grenade the one you're trying to push too hard.

 

[Mid_Life_Crisis]

From what Matsuda says, it sounds like if someone was crazy enough to remove the actuator, without the spring inside it, the wastegate would open on its own and no boost would build.
I wasn`t thinking about removing it, I just like to understand exactly how things work in my car. I am considering redoing the plumbing a bit, and that would require this little bit of knowledge.

 

[240ka]

There's a guy that was posting here on the forums that works/worked for mazda that spoke about adjusting our wastegate so we can build more boost. That way you didn't have to use a MBC.

Let me try and find the thread, I saved it to my favorites somewhere

here it goes. im thinking about doing this myself
http://www.msprotege.com/forum/showthread.php?t=35590&highlight=Blkzoomzoom

 

[matsuda]

There's a guy that was posting here on the forums that works/worked for mazda that spoke about adjusting our wastegate so we can build more boost. That way you didn't have to use a MBC.

Let me try and find the thread, I saved it to my favorites somewhere

here it goes. im thinking about doing this myself
http://www.msprotege.com/forum/showthread.php?t=35590&highlight=Blkzoomzoom

That is an old thread (years before the MS3).

You can adjust the wastegate (to control boost) on a car that does not have electronic boost control but it doesn't apply to the MS3.

 

[matsuda]

From what Matsuda says, it sounds like if someone was crazy enough to remove the actuator, without the spring inside it, the wastegate would open on its own and no boost would build.
I wasn`t thinking about removing it, I just like to understand exactly how things work in my car. I am considering redoing the plumbing a bit, and that would require this little bit of knowledge.

The wastegate actuator is the simple part.

The other side of the equation is understanding the electronic boost control (which controls the amount of pressure in the mechanical actuator).

Note that the actuator has 2 ports: One is on the compressor outlet ("boost pressure") and the other goes to a solenoid valve which controls the pressure in the actuator.