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Discussion Starter · #1 ·
I am sure this has been done, but I am going to line my air box soon and wanted to see the temp difference.
So I taped a temp sensor in my air box on the front side being furthest away from heat sources and closest to the fresh air.
Not sure if that location is the best but it was the easiest at the time.

Time Temp Comment
6:21am 62.5 Car sitting in the garage all night.
6:31am 55.8 10 minutes to include a warm up. coasting down my hill and some light driving
6:36am 52.5 On the highway
6:50am 52.7 Still on the highway
6:56am 52.9 Left the Highway and maybe a mile of lower speeds now parked
7:52am 83.8 Car sitting for an hour

More data to come on my lunch break and on my drive home.
 

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For this to have relevance, you need to compare ambient air temps with IATs as read by the sensor in the car. That is how the MAF sensor determines air mass and how much fuel to use. Taping the sensor to the inner surface of the box will pick up the surface temps of the box more than the temperature of air moving through it.
My car generally stays ~3°-4°F above ambient in normal driving conditions according to the cars sensors, with a small increase to 10° or with traffic and stoplights. I went to the dealer two days ago to get the car serviced and watched the temps during the 30 minute drive. Ambient was ~70°, as long as the car was moving more than 20 mph or so IATs stayed at 73°-74°. At long stop lights it went up a few degrees but went back down in a couple minutes. The car was serviced, and leaving the dealer after about an hour or so IATs were up to 87°-88° from sitting and idling a while. Temps went back down once the car got underway and stabilized again at 3°-4° above ambient.
 

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I track the MAF air temp on my ODBII tool and it runs about 5-6 degress above ambient air temp unless the outside temp is below 60, then about 3-4 above.
 

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Discussion Starter · #4 ·
I track the MAF air temp on my ODBII tool and it runs about 5-6 degress above ambient air temp unless the outside temp is below 60, then about 3-4 above.
Hey Brian, what ODBII tool do you have.
 

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Hey Brian, what ODBII tool do you have.
Veepeak Mini WiFi OBD2 EOBD Scanner Scan Tool Adapter Check Engine Light Diagnostic Trouble Code Reader for iOS iPhone iPad and Android
I use the Dash Command software which displays active Speed, RPM, Coolant temp, Intake temp, Vacuum and a host of other options
$17 Amazon
 

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*The Electrician*
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I have been using a simple ebay Bluetooth dongle with the Android app called "Torque" for my previous OBD2 Honda and Acura, both provide a decent amount of information to either my tablet or my cell phone. I can clear basic engine codes and view a variety of data on a customizable display. I am hoping the same will apply to my Mazda when it arrives.
 
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