photos of gauge cluster boost gauge, part 1
 

I'm further along setting up a gasser economy/vacuum gauge as a boost gauge per jbaj007's instructions (http://www.peachparts.com/shopforum/diesel-discussion/62672-turbo-boost-guage-advice-needed.html?perpage=15&highlight=boost%20gauge%20economy).

See the photos at http://photos.yahoo.com/tabijan in the 126 boost gauge album.

I hooked up a pressure source to feed the reworked gasser economy/vacuum gauge and an Autometer boost gauge for reference.

photo 1 - no pressure input

photo 2 - a little over 5psi on the Autometer gauge an no movement from the gasser gauge

photo 3 - by 7psi on the Autometer gauge the gasser gauge starts to respond

photo 4 - by 10psi on the Autometer gauge the gasser gauge is into the red zone. Ooooh...

photo 5 - by 13psi on the Autometer gauge the gasser gauge is
a half pointer width from the peg.

I don't think the Autometer gauge is accurate. I have a seemingly better made Craftsman vacuum and pressure gauge that reads 1psi higher than the Autometer gauge across the scale. The Craftsman gauge only goes to 10psi so I can't use it to calibrate the gasser gauge. I'm not after 5 decimal places of accuracy anyway.

This was my first shot at resetting the pointer and it looks close to where it should be. I'll know better when I do test runs with the Autometer gauge in the SDL.

It bugs me that the gasser gauge doesn't get off the low end peg sooner. If I calibrate the gauge to peg at 16psi like I'd like it to, it might not get off the low end peg until it senses 10psi.

Sixto
95 S420
87 300SDL

Wow that's pretty cool. I wonder if you can reposition the stopper needle so it'll read higher than 16psi?

Funny you should ask...

Pointer sweep between the pegs is ~90-degrees. I tested just now and it takes ~220-degrees of sweep to get 0-16psi. That's consistent with the 7psi range I get between the pegs. So if you have the pointer relaxed while pointing to the lower left corner of the fuel pump icon (~5-degrees to the left of vertical), it'll hit the outside of the low end peg (travel is unimpeded in a 126 cluster) at 8psi. Bend it over the peg and it continues from 9-16psi between the pegs. The somewhat nice thing if you think in psi is that a horizontal pointer is 5psi.

Sixto
95 S420
87 300SDL