boost guage questions

[Gerard]

I thought those numbers seemed alright. The -20 and -10 are probably
mm.Hg vacuum (read from atmospheric pressure). At idle, on a PSI boost
gauge, it should be 0 psi. 5psi is about 1.3 bar (absolute) and that
seems alright for 3000rpm (from what I recall when my MC engine was
running). What's the boost like higher up the rpm range under full load?

I might be wrong, but I think the confusion is in misreading the scales
on the gauge.

G.