Boost Gauge installation

Checking under the hood where to 'hook in' my (Greddy) boost gauge (D24tic)
I see a small tube coming out of the inlet manifold, it's connected to the throttle body...My best guess is that there is a pressure sensor somwhere in the throttle body, therefore this tube connects it to the inlet manifold. Should I just cut this tube, place a T-piece and then tap off a tube that goes to my mechanical boost gauge ?
Or can I go for an electrical boost gauge (if yes where should I 'hack in') ?

If you could also take a look at my previous post (Performance upgrade 940 Malmö), would appreciate ! :-)

Regards,
Wim

[Peter Milnes]

You can tap in anywhere on the inlet side but do not tap into the vacuum line for obvious reasons! You should find that the pipe goes from the inlet manifold to the pump then also to the boost overpressure switch, usually mounted on the strut tower. It would probably be better to tap into this tube (between pump and overpressure switch) rather than the already short tube from the manifold. There is no reason why you should not use this as your pressure source. I am preparing to do this but need a gauge mounting pod for my windscreen pillar.

Should you decide to use an electrical gauge you will need to mount a sensor (which needs to be able to "read" the pressure to convert into an electrical signal) so that the gauge will work. It is a little more complicated because of this.

All the best, Peter.