Twin turbo boost gauge

[johninKY]

Not my problem but this person which I believe a 94 twin turbo Legacy wants
to install a boost guage and can't find a good line to T into. I've never
even seen a twin turbo and suggested using the line to the wastegate
controller. This person tried but the ggauge only shows vacuum readings.
Seems strange to me. Anyone with any experience with this know where to
splice in the line for the boost guage?

 

[iksalama]

how about the line leading to his blow off valve?

 

[mike]

Tee the gauge into any vacuum line going into the manifold. The Blow of
valve connected to the intercooler would be fine. If you tee of the
secondary turbo's Blow of valve you will not get the desired result, you
only see boost pressure when its running & no vacuum information.
Teeing of to the waste gate is not a good idea as the computer manipulates
this pressure with a solenoid valve and it is not the true boost pressure
( will give you vacuum but not boost pressure until the waste gate is opened
by the computer by which time the manifold should be at approx max pressure)

I have teed my gauge at a nipple on the manifold located above (but not
directly connected to) the secondary turbo.
Hope this helps
Mike