I have fitted a turbotech manual boost controller to my 84 dr30. The turbo is standard both in size and position, i.e buried in the bottom of the engine bay, and as you would all know access is a bit easier from the bottom, but still a bit hard to see and access. My question is this. The line that runs from the turbo to the wastegate on my car has a "T" in it with one side running to the compressor side of the turbo and the other also attaching to the compressor side, but a little higher up. Do I block off one of these, or simply splice in downstream of the "T"??? What is this second line for??
Any help would be much appreciated. Thanks.

Follow the line from the t-piece and see where it goes...
I would connect it before the t-piece as close to the compressor cover as poossible.

Thanks for the response. Both lines connect to the compressor side of the turbo. One goes to the "body" of the turbo, connecting with a push on hose and clamp, one to the "output nosel" of the compressor, right where it connects to rubber intercooler piping, but it has a screw in connector.?

Pix M8.
They speak a thousand words.

Bottom line is you need to tee the line from the compressor housing to the wastegate can and bleed off pressure from that line.

The line from the compressor housing to the tee needs a restrictor in place.
I use a 2 mm restrictor in my electric boost controller.

L8tr
E

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The older we get........the faster we used to be!

Wish I could give you a photo! Can barely fit a stubby screwdriver in there, let alone a camera. Thanks for the advice, but I'm not clear on what you mean. Why is a restrictor needed? Is this Just a FJ20 thing?

Nup, all boost controllers usually need a restrictor in the line that comes from the compressor housing.

There is a lot of airflow available from that 6mm airline and the boost controller must bleed pressure off between the compressor housing and the wastegate can in order to work. It would need to be considerably larger than 6mm pipe and a whopping great valve to bleed off sufficient air pressure.
If the amount of airflow available exceeds the ability of the bleed valve to bypass the controller will not work or increase boost only a bit and it will just hiss.

So you restrict the available flow rate BEFORE your boost controller is tee'd into the line and so a much smaller volume of air is bled off from the wastegate can.

Mine is simply an old carby main jet jammed into the pipe.

L8tr
E

So what you are saying is that I need to Partially block or "restrict " flow into the boost controller with some sort of block in the line.

Not exactly!
You need to restrict the airflow FROM the compressor nipple BEFORE it gets to the controller T-piece.
L8tr
E