Question where does the sensor fit/mount too to get the signal reading back to the guage ,supplied is 1/8th npt adapter help needed please.

 

Unscrew the bottom brass threaded bit, and at a hardware store find a 4 or 5mm hose nipple which has the same male thread as the upper part (which you just screwed the bottom out of)

Something like this, but then with the right thread, so it fits into the top hex part in your picture.


Then run a piece of hose from the manifold (central collector area has 1 unused nipple, with a rubber cap, or T into the smaller DV hose.

 

so why please tell me does it not say this in the stack instructions?

 

I don't really know.
Maybe Stack expect people to drill and tap their manifold (which is quite dumb IMHO, as nobody would go to the trouble of removing the manifold and drilling/tapping)

But the correct hose barb will at most cost a fiver, and that way you can use the more normal way of using a bit of hose connected to the unused nipple on the manifold.

Or maybe their boost gauge runs on the same sender as an oil or fuel pressure guage which normally is screwed into the engine, a sandwich plate or a fuel line adapter .
This saves them from having to manufacture 3 seperate sender units (oil pressure, turbo pressure and fuel pressure)thus making them able to make manufacturing cheaper.

After looking a bit better I think you actually need a male hose barb, that screws onto the thread, not a male one which screws into a thread, and is pictured in my pic above.

This would be what you need.

 

cheers mate think your right most of the sender units for guages are of the same type so cheaper for manufacturing as you say thanks for that ,my initial thought was do i screw this into the manifold you would have thought that they would of supplied the male adapter wouldnt you ?