Alternative CLT source

[thedrew]

Hey folks,

using MS3x, 1.5.0

Is it possible to use a generic sensor as the CLT source? I have an air cooled engine, and I use thermocouples to measure head temp through a thermocouple amplifier. I'm trying to see if I could tell the ECU to use the 0-5v output of the thermocouple amp as the CLT source.

Thanks!

[whittlebeast]

It may be easiest to do an oil temp sensor. All you need is a temp sensor that changes resistance as the oil temp changes.

The MS world simply has cold engine fuel enrichment as a function of temperature.

Andy

[fast930]

If the car is a porsche use a BMW 325 coolant sensor. It will thread into the left cam cover. As stated above it's only used for warmup enrichment

[racingmini_mtl]

Using the oil temperature is usually not the best choice because it will change too slowly. You're better off using a head temperature sensor.

And you cannot use a 0-5V signal on the CLT input without changing the input circuit: the bias resistor would interfere. I'm not sure you can correctly calibrate the sensor even with the correct circuit because the code expects an NTC type of calibration.

Jean

[thedrew]

I was hoping in software I could just say "use this input as the CLT source"

but apparently no

[fast930]

I was using cht and it worked fine, but I'm here in south Florida so the oil temp works great.

[Matt Cramer]

It looks as if you could deal with the bias resistor by using a buffer circuit and write a custom INC file to convert a thermocouple output to temperature, since the code's internal look up is simply to use a table that tells it "If the coolant input ADC is X, the temperature is Y." TunerStudio uses a model of an NTC sensor to generate look up tables, but it can also write the lookup table from an externally generated file.

[vw_chuck]

You should be able to use a generic sensor as the CHT input. If you can't that is pretty lame. I was hoping to do the same thing with thermocouple amp on an air-cooled.

[thedrew]

You should be able to use a generic sensor as the CHT input. If you can't that is pretty lame. I was hoping to do the same thing with thermocouple amp on an air-cooled.

you can, but you can't say "use this generic sensor for my warmup enrichment" which is what I want to do

[billr]

I think Matt C is saying you can do that by making a custom LUT for the standard CLT input.

[Matt Cramer]

I think Matt C is saying you can do that by making a custom LUT for the standard CLT input.

Correct. The MS3 allows it but you need to make the look up table yourself.

[vern_k]

I am using a head temp sensor in place of a CLT on my VG30E, mapped the sensor out put at a couple temps then crossed it with the FSM and used the calibration tool in Tuner Studio, set the gauge to extended. I was able to stay with in a couple degrees of the reading I get from the infrared thermometer on the sensor