[alex_gprix]

Hey everyone, I am hoping that someone can share some insight on intake temperatures.

Long story short, before installing a controversial intake (unfortunately required in order to fit the BMS oil catch can). I decided to try out Bimmer Link to monitor my IAT before and after the install to decide if the BMS intake made a negative difference and thus I would try to retrofit the oil catch can and leave my stock air box.

MY QUESTION: Bimmer link seems to show two sensors;
1) "Intake air temp" (Measuring about 45C with 30C ambient)
2) "Intake air temp before throttle valve" (Measuring 80-90C)

My "before valve" temp is insanely high and I'm wondering if anyone can share some knowledge on the two sensors? I'm assuming the IAT is part of the MAF sensor, but what is this "before throttle valve"???

Thanks all!!

[msendit]

Originally Posted by alex_gprix

My "before valve" temp is insanely high and I'm wondering if anyone can share some knowledge on the two sensors? I'm assuming the IAT is part of the MAF sensor, but what is this "before throttle valve"???

I think that's the charged air temp in the intake manifold -- after the turbo. Once you compress the air, it gets hotter.
At least that's what I always assumed for my B58, which has a similar sensor.

[alex_gprix]

Originally Posted by msendit

I think that's the charged air temp in the intake manifold -- after the turbo. Once you compress the air, it gets hotter.
At least that's what I always assumed for my B58, which has a similar sensor.

That’s sort of what I was thinking. However wouldn’t this sensor be after the intercooler? I’m not familiar enough with air temps, but 90C seems really hot if that’s the temp after flowing through the stock intercooler?

[PeanuKeeyes]

Originally Posted by alex_gprix

That’s sort of what I was thinking. However wouldn’t this sensor be after the intercooler? I’m not familiar enough with air temps, but 90C seems really hot if that’s the temp after flowing through the stock intercooler?

That does seem hot for that.. but 90c is more or less the operating temp for the engine. Both the oil and coolant temps in my 228i read about 90c on average according to my obdII display. Assuming those are correct.

[msendit]

Originally Posted by alex_gprix

That’s sort of what I was thinking. However wouldn’t this sensor be after the intercooler? I’m not familiar enough with air temps, but 90C seems really hot if that’s the temp after flowing through the stock intercooler?

The folks on the 3er forum claim it's in the charge pipe (so, before the intercooler), and that the IAT one is after (so, not part of the MAF).

To be fair, I haven't looked to closely myself which sensor is where. But I routinely see 100+C on track in one of the "air temps" my datalogger grabs.

https://f30.bimmerpost.com/forums/sh....php?t=1717248

[alex_gprix]

Thanks mate!

I found this diagram in the B46 technical document. It looks like there is a sensor (#5, I believe the MAF) right after the filter, as well as (#7) at the throttle body.

It will be interesting to compare these temps after an intercooler upgrade!
Cheers!

[MarcoZandrini]

Yes, since about 2004, BMW MAFs contain the IAT sensor. You can confirm this by removing the MAF connector and counting the pins. It should have at least 5 pins. Pre-2004 MAFs had 3 pins.

[alex_gprix]

Originally Posted by PeanuKeeyes

That does seem hot for that.. but 90c is more or less the operating temp for the engine. Both the oil and coolant temps in my 228i read about 90c on average according to my obdII display. Assuming those are correct.

Yeah, my first thoughts were that the intercooler would cool the air back down near the initial intake temps, but that is just my assumption with no real merit.

I've begun to notice that under turbo boost is when its reaching near 100C, then slowly cools back down to around 60-70 when I'm just coasting without any meaningful acceleration.

[alex_gprix]

Originally Posted by MarcoZandrini

Yes, since about 2004, BMW MAFs contain the IAT sensor. You can confirm this by removing the MAF connector and counting the pins. It should have at least 5 pins. Pre-2004 MAFs had 3 pins.

Thank you for that info!

[MarcoZandrini]

Originally Posted by alex_gprix

Thank you for that info!

You're welcome!