I decided to have a play around and get the boost gauge working in PSI for boost and inHg for vacuum. First try, the numbers jump when going 10 or higher. I could set conditions to compensate for this, but I haven't bothered yet.

I have installed the boost gauge in the car. It is not really visible enough in the sunlight, I would guess vthat I have not got the window I cleared in the tach face clear enough. It looks like it is clouding up when the sun strikes it.

I have now removed the tach again and cut out the face in front of the gauge screen. It is much clearer now, so see what it looks like in the sun tomorrow.

Here is the code that I am currently running, gives the boost in bar, with atmospheric compensation. It also is set up to keep the figures in the same relative postion with or without the negative sign. I have truncated the u8glib entries, if you have a different screen, you will need to copy the right constructor line from the u8glib hello world example.

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Well, a little further along. The barometer module arrived, so I managed to get it working to give the baseline atmospheric pressure to zero the gauge. This means that the gauge should always give the right boost figures at any elevation.
I test fitted it into a spare tach I have. I dropped the OLED screen onto the floor and cracked it, these are really delicate. The screen is now only showing what looks like every second pixel row, so not as sharp as it shoiuld be.

I am in the process of making a small boost to fit in the dash of my MX6. I don't know why this was not a factory fitment, I have a 1990 Capri Turbo that has one, and I think that the Probe GT might have come with one?
I started off by getting this small one, as I wanted something un-obtrusive, and I wanted to put it close to my line of sight.