Lotus Water Temperature

 

How to: Connect IQ3 to stock water temperature sensor

This article provides information on how to wire/connect the stock water temperature sensor to a RacePak IQ3 Dash/Data Logger.  This information covers a Lotus Exige S (2007), other Lotus years/models may vary.

REQUIREMENTS:


  1. Bullet  RacePak IQ3 Dash

  2. Bullet  DataLink II software

  3. Bullet  RacePak universal module

  4. Bullet  Wire splicer & solder gun & electrical tape

Wire to splice Orange/Black.

Step 1

Locate the water temperature sensor -- this is on the driver side of the cylinder head.  Splice into the #64 OB ORANGE/BLACK wire (see diagram).  Do NOT cut the wire.

Below is a picture of the water sensor in the cylinder head and the wires running out of the sensor.

Water Temperature Sensor

Step 2

Run the spliced wire to the RacePak Universal 4 port module.  Don’t use the ground connection.  Use the one spliced wire and run it to the “Signal” connector in the RacePak module.

Step 3

Once wired up, you will now need to set the calibration values for the OEM water temperature sensor via the DataLink II software.  Calibration settings are listed below.     


Calibration was done using the Calibrate button and sampling the voltage at a known temperature values.  I used both ambient readings and readings obtained from the stock OEM dash once over 160 F.  This is best done before removing the OEM dash so you can use it for your reference temp readings (set points).


If you’ll notice I’m still using a 0 - 5 Volts sensor type (analog signal type).  Water temperature sensor is a resistance type unit -- and as the temperature increases you’ll see the voltage drop.  The data points go thru linear interpolation.  I added some smoothing (about 65 points but feel free to experiment).

RacePak Universal 4 port Module