AAZ help! Quantum turbo T3

[Jagerauto]

Ok I'm putting my motor together and need to know what to do with this turbo.

It's a T3 off an 86 Quantum.

I've clocked it to work perfectly on the AAZ manifold. To where the drain is pointed slightly down, the waste gate is in the way or else I could point it straight down.

What flange do I need for the return line on the turbo. I see a bunch on eBay, but I'm unsure as to which one i need. I want one with an AN fitting so I can get a measurement and have a nice line made up.

Next, on the waste gate there are two holes or fittings. The larger one goes to the cold side of the turbo. Where does the smaller one go? I was thinking the pump? I don't remember.

Pic of the progress

[theman53]

smaller one goes on the cold side of the turbo housing BEFORE the compressor wheel.

I stray away from the ebay stuff. I have a 1/2npt to 10 JIC fitting on mine then run it. JIC is the same stuff as AN but all the AN I see is aluminum and crappy.

[Jagerauto]

Still not sure about the waste gate. The turbo has a rubber hose that goes to metal line and screws into the larger hole. That line comes from the cold side right by the intake.

[410]

The smaller fitting on the wastegate can just be open to atmosphere.  It goes to the other side of the diaphragm.  This port can be used to open the wastegate at a lower psi by applying vacuum to the small fitting.  This can come in handy for people looking for a little more economy. 

[Jagerauto]

Can it be used to keep the waste gate closed for more psi? Hmm.

[theman53]

The large rubber hose that you can see should go to the large threaded hole in the wastegate. The smaller threaded hole in the wastegate should go to the intake before the compressor wheel, not after like the large one. Right where the hose clamps on from your air filter there should be a small fitting. That is how it was hooked up stock anyhow.

[Jagerauto]

Yea there is a small hole that goes right through before the wheel. No fitting.. I guess that would pull a vacuum. But I want power! Haha.

[theman53]

If you have a T3 off of the VW that hole that 410 is talking about is a different hole. The bottom of the wastegate is what he is talking about. On the Vw T3 the waste gate has 2 openings on the top side of the diaphragm on the waste gate. That is what I am talking about running to the housing pre compressor..

If you look in this picture you can see it on top of my waste gate. The little one blows air continuously into the compressor housing when you are boosting*unless you have a manual boost controller* I didn't hook mine up as the Mercedes doesn't have a hole in the housing to hook it up to, but I am adding it this time.

said picture:
http://db.tt/zjHfaVkf

[410]

Can it be used to keep the waste gate closed for more psi? Hmm.

If you put vacuum to that line the wastegate opens sooner and reduces psi.  Like theman53 says it normally goes to the turbo inlet side but you can leave it open to atmosphere.  That will give you the most boost without going to a boost controller or air bleed on the bigger fitting.

[theman53]

Can it be used to keep the waste gate closed for more psi? Hmm.

If you put vacuum to that line the wastegate opens sooner and reduces psi.  Like theman53 says it normally goes to the turbo inlet side but you can leave it open to atmosphere.  That will give you the most boost without going to a boost controller or air bleed on the bigger fitting.

I would think that one on top would cause it to open later if you put vacuum to it. It only bleeds the boost off, so if you pulled it out with vacuum wouldn't it need more boost to push on the diaphragm and open the waste gate? If you put vacuum on the bottom of the waste gate I could see it opening it sooner, but that other threaded on top I could only see it opening sooner if you plugged it letting all the boost act on the diaphragm.

[410]

Question for the OP.  Can we get a pic of the fittings on your turbo?

[Jagerauto]

Yea ill take some tomorrow.

[Jagerauto]

[theman53]

Yep, Little threaded one goes into the compressor housing where the rubber deal is. Big threaded one comes from the pressure side of the housing and actuates the waste gate...supplies little threaded one with air too.

[410]

You're right Lucas.  The only reason I can think of for the extra line is to allow a bit of airflow on the diaphragm to keep it cool.