[urq] Red CGT vs. MB/RR digital dash in an ur q.

[Steve Eiche]

A couple of weeks ago I received my new RR digital dash from Germany.  
Quite a deal at 350 Euro IMHO.  What was the first thing that I did?  
Well, I disassembled it of course!

The point of buying this dash was to have the correct digital dash for 
my 20V conversion on my (used to be) '82 ur q.  I also have a few CGT 
digital dashes including a brand new one, which have been proven to work 
with with 10 and 20V ur qs with only a couple of issues.  I knew that 
there must be some differences between the CGT and RR dash, and now I 
finally know exactly what they are.

First off, the CGT dash is set to use the 60 liter tank.  The ur q has 
the 90 liter tank.  This can easy be changed with a simple jumper on the 
circuit board, which I have just verified on the bench.  

The second difference is in the warning light display, and the CGT has a 
different configuration for the display.  The difference here is in the 
position of several of the lights, and the addition of indicators for 
the front and rear fog lights.

As for the circuitry in the dashes, the MB/RR dashes use exactly the 
same circuit board as the late CGT dashes (the early CGT circuit boards 
had a couple of "mistakes" that were corrected with some rework, but 
were schematically the same).  The later dash does have a different 
program in the processor (comes up as "4" in the calibration mode, 
instead of "2" on the CGT - I believe the difference in the program 
_may_ be due to the higher redline on the MB/RR than on the CGT but I 
can't read the program to compare as they are burned-in as a masked 
ROM), and some of the signal conditioning circuitry for the fuel 
consumption circuitry was eliminated on the later dash.   The ur q dash 
also uses the  more orange display filters like the late CGT dashes, 
unlike the red display on the early CGT.

Bottom line, if you want to install a red digital dash in an ur q, it is 
possible to make it work properly, even with the fuel consumption 
computer (assuming that you have can get an air flow sensor on a 10V, or 
just hook up the fuel consumption signal from the ECO on a 20V). 

There you go.  Probably more info that you wanted or cared to know, but 
hopefully it will help someone...

Steve