I just finished installing a IQ3 dash-only to replace the dash that was part of my G2X in my Miata.
As part of this project, I also added a pair of USMs to take data from my Autometer Elite gauges (they have a 0-5V out to feed a data system), and a bunch of new sensors & data feeds. The G2X was already connected to my ECU (Megasquirt) and supplying 10 channels of data.
The new data feeds to the USMs are:
Autometer Oil Pressure, Oil Temp and Water Pressure gauge outputsUSM/Sensor programming
GM coolant temperature sensor at output of radiator (GM 15326386). Sensor and pigtail sourced from http://www.bmotorsports.com.
VDO 0-30psi pressure sensor in coolant system (VDO 360-043). Sourced from http://www.egauges.com/
Fuel Level (piggy-backed off the back of the Miata's dash)
Charge Light from stock dash as trigger (to use as IQ3 warning)
Brake Light trigger
The GM sensor was configured as a GM degF temp sensor and worked fine.
The VDO sensor was configured as a 10-180 ohm sensor and the 5 data points VDO supplied were used to build a calibration table.
The Miata fuel level feed took some work, and I don't have my notes on what I settled on with me now.Sensor & Autometer Elite Notes
It wasn't immediately obvious to me, but any 2-wire sensor should be connected to the signal and ground terminals on the USM.
VDO doesn't publish their sensor resistance curves. I had to call them (800-265-1818) and they'd only give me 3 data points. If someone else uses the same sensor, here's the data I was able to get from them:
Bar Target Resistance/Resistance Range (ohms)
Also, Autometer doesn't publish a curve for their 0-100psi pressure gauge datalogger output. It's 0.5v=0 psi and 4.5v=100psi. The chart they publish for their temperature gauge seems to cover 60-340 degrees even though some of their temp gauges only go to 260 degrees. The same curve does seem to work for both temp ranges.Pictures
A couple of shots of the IQ3 and the Autometer water temp gauge:
The other gauges:
Roughed-in USM install:
Thanks to everyone at Racepak that helped me get this going!