The gauge may go "off the scale" or may not read the correct boost pressure, ideally it would need to be re-calibrated with the scale modified
My thinking is that it is a linear scale driven from an absolute value, not a variable voltage.
So quick !Removed! packet calculation, 1.2 bar is represented by a sweep of 90 degrees = 75deg/bar
So 2 bar would require a sweep of 75*2= 150deg.
I have tried the pointer sweeping from right to left, with gauge in pod. The needle just misses at both edges, but is achivable.
My car has actual recorded data (after I fixed my turbo) showing 30psi (very briefly), which would require a sweep of 180 deg to show as 2.4 bar.
At the end of the day, I want to see if I can get the original gauges working, and hopefully later this afternoon, after usual Sunday mornig Family stuff, I will have an answer.
As for accuracy thing, I curently have an analogue turbo gauge (driven from inlet manifold). When I first hooked it up I could get it to shoot past 27 psi quite regularly, but with a real annoying buzzing. I had to restrict the input so much that it only indicates that its getting to about 20, but on average abourt 17. The point is, I now now what "normal" operation of my turbo is. I wouldn't care if it had no numbers on the dial, all I care is that it is behaving the same way that I have previously witnessed. If it starts misbehaving then time to look at turbo before it goes bang again.
Consistent readings (i.e same input produces same output (not a random output)) are better than no readings.