In this blog, we discuss the AEM IAT (Intake Air Temperature) Sensor types and which one is best for a Speed Density upgrade in your Subaru.
What is an IAT Sensor?
IAT is short for intake air temperature. This measures the temperature of the air, which determines its density, allowing the ECU to adjust accordingly. Colder air is more dense, while warmer air is less dense, which changes the air-to-fuel ratio.
For some applications, usually due to a larger turbo, the intake airflow is greater than the MAF's ability to read it. Therefore, the ECU requires a different method to determine the amount of air entering the engine, so an Intake Air Temperature Sensor is installed.
Given the limitations of the factory IAT sensor location in the MAF housing, relocating closer to the throttle body leads to better accuracy in the ECU's calculation of the air temperature. This can be done with our Hybrid MAF Kit
You can find a full explanation of IAT, MAF, and Speed Density here.
What Makes the AEM IAT Sensors Different?
There are two AEM IAT sensors used for speed density - 1/8" NPT and 3/8" NPT. The difference lies in the thread pitch (1/8 NPT vs. 3/8 NPT) and the sensor scaling, so that the ECU can accurately pick up the temperature reading.
The biggest difference is that the connector that plugs into the sensors are not the same. Before purchasing the iWire Speed Density Wiring Kit or our Hybrid MAF kit, you'll need to determine which sensor you have or require.
1/8" NPT Connector Type
3/8" NPT Connector Type
Which AEM Sensor Do I Need?
Some aftermarket intercoolers (top mount and front mount) already have a welded-in bung for a specific IAT sensor. The thread type can be measured or will be listed in the documentation you receive when purchasing the intercooler.
Since every build is unique, the best way to find the correct sensor type is to ask your tuner. They may have a preference and can recommend what makes the most sense for your build.
