What is the right place to tap the x pipe for the boost gauge?

 

You can tap it on the hot side, or the cold side, or tap the MAP line with a brass T

The hot side is right after the turbo compressor, which will read a bit higher then the cold side.

Cold side is after the intercooler... RiffRaff sells a nice plug that removes the Intake Air Heater and replaces it with a plug that you can install the boost gauge there...

Riffraff Diesel: RDP AIH Tapped Fitting

Or you can build a Brass T with barbed fittings on two sides and a 1/8" compression fitting on the other...

 

CSIPSD, is there a preferred side to mount it? i know it can be done on either side, but which one would be more suited for accurate monitoring? I am assuming cold side as that is the side going to the motor?

 

Cold side is where most mount it, so your numbers would be comparable.

 

ok good to know. thanks bud