Doward

Seems to me, that if the IAT is used to help figure air mass, then you'd want the IAT near the MAF, so they measure the same air, at the same time.

Seem sound?

Where do you guys mount your IATs? I'm thinking upstream of the turbo, in front of the MAF, right behind the air filter....

1981TTA

If you have a MAF sensor, you don't "need" the IAT sensor to figure air mass. (Under steady state conditions....) The sensor output tells you the Mass Air Flow. However, on super/turbo charged applications, it is helpful to know the temperature of the air going into the combustion chamber. This can be used to adjust spark timing so that knock is avoided. The idea would be to measure air temperature as close to the port as possible (i.e. in the intake manifold after any charging/intercooling devices). Technically, this could also be called a Manifold Air Temperature (MAT) sensor. I don't know if there is any electrical difference between IAT and MAT sensors. I would think manifold temperatures will generally experience a wider range of temperatures relative to air cleaner (i.e. mounted pre-Throttle Body) temperatures. But, I think the only difference is in the method of how the sensor is packaged. In my limited experience, I've noticed pre-TB mounted sensors come in plastic looking housings while manifold mounted sensors are brass housings.

So, I'd suggest mounting the temperature sensor in the manifold *after* the charging/cooling system. If I remember correctly, there was a discussion on one of TGO's boards that compared response rates of various IAT/MAT sensors. Since boosted intake temperatures can change very quickly, it's important to have a sensor that responds reasonably quickly. Might be worth a quick search to see what comes up......?

Doward

Yep, I saw that thread - very nice. Thankfully, my stock V6 one is already open.