While waiting to get machine time to get my LCAs and camber plates built, I wanted to get an oil temperature gauge installed as one of my winter projects. I really didn’t want to install a sending unit on the driver side head port as many have done as I have installed the 987 airbox/MAF and there just isn’t a lot of room in that area now to get my hands/tools in there. I had looked at a thread on rennlist by Ahsai a long time ago on the possibility of using the signal from the temp/level sensor in the sump to drive a gauge.
So I decided to build and program one using some of the information Ahsai posted and tweaking it a bit. I purchased a used temp/level sensor probe and wired it into my DME in place of the one in my engine and used a NIST traceable hot oil temperature bath to heat the sensor to map out the voltage signal from the sensor to 300 F and mapped that signal to what the gauge needs to indicate the respective temperature.
I breadboarded up a driver and programmed the chip with the math function to take the signal from the sensor and then output the required signal to the gauge. The component receiving the signal from the DME tap has 500k ohm resistive value to not degrade the signal current the DME sees. I have installed the gauge/breadboard prototype and verified accurate function through Durametric. With everything now functioning I will make a PCB and a simple wire harness/box combination to install the device permanently.
Bench prototype
DME Wiretap
DME Wiring
Prototype Onboard Testing
