IAT Sensor Placment In A CAI
07-19-2012, 10:28 AM
#1
IAT Sensor Placment In A CAI I put this together yesterday but was wondering if it matters where I place the IAT sensor? I was just going to see where the stock plug would reach and place it somewhere around there. Not opposed to extending the IAT harness to move it somewhere else if it beneficial.
07-19-2012, 11:33 AM
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Hopefully, this is a fair weather car. Otherwise, you're in for some trouble. 
I've relocated several IAT sensors into the front bumper (just about where your pipe sits). Ideally, you want to find a spot that'll stay dry. I haven't had a sensor fail due to moisture yet. But, I wouldn't consider it an impossibility.
I've relocated several IAT sensors into the front bumper (just about where your pipe sits). Ideally, you want to find a spot that'll stay dry. I haven't had a sensor fail due to moisture yet. But, I wouldn't consider it an impossibility.
07-19-2012, 11:13 PM
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IAT does not tell you manifold air temp and it's not supposed to. It'd be
called a manifold air temp sensor. The expansion valve that is the throttle
will drop the temperature variably except for WOT and the IAT-as-MAT
would just be a hoax.
Given that your CAI works, i.e. you are pulling air at ambient temp, you
can put the IAT anywhere that it won't get any offset. Because then air
is air.
Any skew at very low RPM can be taken out as a rich error by closed loop.
Letting your IAT get faked hot, though, makes a lean error in open loop
speed density which you can't null, and varies day by day.
Mine is up in the cowl sump under the plastic trim. Actually a Digi-Key
thermistor with the same curve, which is smaller.
called a manifold air temp sensor. The expansion valve that is the throttle
will drop the temperature variably except for WOT and the IAT-as-MAT
would just be a hoax.
Given that your CAI works, i.e. you are pulling air at ambient temp, you
can put the IAT anywhere that it won't get any offset. Because then air
is air.
Any skew at very low RPM can be taken out as a rich error by closed loop.
Letting your IAT get faked hot, though, makes a lean error in open loop
speed density which you can't null, and varies day by day.
Mine is up in the cowl sump under the plastic trim. Actually a Digi-Key
thermistor with the same curve, which is smaller.
07-20-2012, 12:41 AM
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Exactly. IAT = Intake Air Temp. It's modeled along with ECT's based on airflow to assume temps in the cylinder. If it was going to error slightly, I'd much rather it be on the cool side vs. the hot side to avoid heat soak caused lean scenarios.
Not to mention, air is a much better insulator than it is a conductor. For as little time the air stays in the induction tract, I highly doubt (nor have I seen evidence of) it's actually picking up that much heat. Think about pre-heating an oven. It's not instantaneous and that's with 0 grams/sec of airflow.
Not to mention, air is a much better insulator than it is a conductor. For as little time the air stays in the induction tract, I highly doubt (nor have I seen evidence of) it's actually picking up that much heat. Think about pre-heating an oven. It's not instantaneous and that's with 0 grams/sec of airflow.
