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Importance of Intake air temp sensor location

MoTeC M1 Software Tutorial

Discussion and questions related to the course MoTeC M1 Software Tutorial


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I have my Intake temp sensor mounted in my intercooler pipe a few inches in front of the throttle. The diagram from M1Tune has the sensor mounted inside the intake manifold.

I know this is a critical sensor for the fuel calculation so should I consider re mounting the sensor to read from inside the intake manifold?

Bob

I prefer to leave it in the charge pipe as it's less susceptible to heat soak there.

You have the option to have it in the manifold or the air intake pipe. You need to select the correct "mode" under "Inlet Manifold Temperature Mode". If in the charge pipe it should be "not in use"

I've used both locations in our 86 and seen very little affect on the calibration, however the FA20 does use a plastic inlet manifold which is likely to heat soak less than a cast alloy one. The aim is to accurately model the charge temp as the air enters the cylinder. In my own experience (and I believe MoTeC disagree with me here), I tend to see more consistent results with the air temp sensor in the charge pipe pre throttle and this is my personal preference.

The inlet manifold temp mode Chris mentioned can be used regardless where you've mounted the sensor. It allows the final temp value that the M1 uses in the fuel calculation to be biased towards the IAT or the ECT depending on operating conditions. For example at low air speed such as idle, there is a lot of time for the inlet charge to pick up temperature from the inlet manifold and hence the ECT actually has a large influence on charge temp. At high air speed however the charge temp is likely to be closer to the IAT value. As a word of warning, short of adding a thermocouple right by the inlet valves, accurately tuning this table is tricky at best.