the stock IAT sensor location sucks: test results
07-18-02, 02:07 AM
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the stock IAT sensor location sucks: test results
Did some testing tonight, during the last minute of a 15 minutes steady state cruise:
Ambient air temperature: 27C
IAT sensor reading (PFC):37C
Temp. reading at elbow: 100F (38C)
Gap of +1C.
Heat the engine up with about 6 full boost runs then stop, turn around, repeat.
Ambient: 27C
IAT: 40C
Elbow: 114F (46C)
Gap of about 14F (+6C)
Pull over and wait for 3 minutes.
Ambient: 28C
IAT: 40C
Elbow: 125F (52C)
Gap: +12C
Sit for 5 minutes, car running.
Ambient: 28C
IAT: 50C
Elbow: 127F (53C)
Gap: +3C
Drive for another couple of minutes, then freeway speeds for 10 more.
Ambient: 28C
IAT: 40C
Elbow: 86F (30C)
Gap: -10C
The UIM is a great big heatsink for the stock sensor.
I am going to pull the stock sensor and check it's reaction time to other sensors. But I know it's got to be the location, location, location.
Ambient air temperature: 27C
IAT sensor reading (PFC):37C
Temp. reading at elbow: 100F (38C)
Gap of +1C.
Heat the engine up with about 6 full boost runs then stop, turn around, repeat.
Ambient: 27C
IAT: 40C
Elbow: 114F (46C)
Gap of about 14F (+6C)
Pull over and wait for 3 minutes.
Ambient: 28C
IAT: 40C
Elbow: 125F (52C)
Gap: +12C
Sit for 5 minutes, car running.
Ambient: 28C
IAT: 50C
Elbow: 127F (53C)
Gap: +3C
Drive for another couple of minutes, then freeway speeds for 10 more.
Ambient: 28C
IAT: 40C
Elbow: 86F (30C)
Gap: -10C
The UIM is a great big heatsink for the stock sensor.
I am going to pull the stock sensor and check it's reaction time to other sensors. But I know it's got to be the location, location, location.
07-18-02, 09:40 AM
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IAT = Intake Air Temperature sensor.
Wade and Piston Eater,
My thought exactly! Move the whole damn thing (if it responds fairly decently to testing for quickness/sensitivity) or replace it with a faster acting sensor and figure out what to do to splice it in to the stock harness (voltage output matching.)
Wade and Piston Eater,
My thought exactly! Move the whole damn thing (if it responds fairly decently to testing for quickness/sensitivity) or replace it with a faster acting sensor and figure out what to do to splice it in to the stock harness (voltage output matching.)
07-18-02, 10:05 AM
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What kind of sensor did you use in the elbow???
You know what would be a interesting test is this same test with a stock IC. I wonder how many people over the years thought the stock IC couldn't bring the temps down but it was really the sensor the whole time haha
I'm going to look at mouning mine in the underside of the elbow or IC pipes, now sure which yet. I need to find some good wire to use to extend it long enough.
I've been thinking for about half a year now that this was a issue but didnt have another temp sensor to check it with. I'm glad you were able to do this.
BTW - did you stay on the freeway long enough to see if the IAT ever matched the elbow temps??? If so how long did it take???
STEPHEN
You know what would be a interesting test is this same test with a stock IC. I wonder how many people over the years thought the stock IC couldn't bring the temps down but it was really the sensor the whole time haha
I'm going to look at mouning mine in the underside of the elbow or IC pipes, now sure which yet. I need to find some good wire to use to extend it long enough.
I've been thinking for about half a year now that this was a issue but didnt have another temp sensor to check it with. I'm glad you were able to do this.
BTW - did you stay on the freeway long enough to see if the IAT ever matched the elbow temps??? If so how long did it take???
STEPHEN
07-18-02, 10:32 AM
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Hey, this is good stuff, Badog. My buddies and I are constantly comparing IAT's along our power FCs. It seems like my buddy's FMIC yields from 5-10 degrees cooler than my M2 large MS, while my other friend's stock IC gives about 20 degrees above mine.
I've often wondered if heat soak of the sensor was leading to inaccurate readings and if the sensor was actually reading in realtime...
I've often wondered if heat soak of the sensor was leading to inaccurate readings and if the sensor was actually reading in realtime...
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07-18-02, 12:30 PM
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Originally posted by SPOautos
What kind of sensor did you use in the elbow???
You know what would be a interesting test is this same test with a stock IC. I wonder how many people over the years thought the stock IC couldn't bring the temps down but it was really the sensor the whole time haha
I'm going to look at mouning mine in the underside of the elbow or IC pipes, now sure which yet. I need to find some good wire to use to extend it long enough.
I've been thinking for about half a year now that this was a issue but didnt have another temp sensor to check it with. I'm glad you were able to do this.
BTW - did you stay on the freeway long enough to see if the IAT ever matched the elbow temps??? If so how long did it take???
STEPHEN
What kind of sensor did you use in the elbow???
You know what would be a interesting test is this same test with a stock IC. I wonder how many people over the years thought the stock IC couldn't bring the temps down but it was really the sensor the whole time haha
I'm going to look at mouning mine in the underside of the elbow or IC pipes, now sure which yet. I need to find some good wire to use to extend it long enough.
I've been thinking for about half a year now that this was a issue but didnt have another temp sensor to check it with. I'm glad you were able to do this.
BTW - did you stay on the freeway long enough to see if the IAT ever matched the elbow temps??? If so how long did it take???
STEPHEN
I posted data on this forum with the stock IC, before I did the FMIC. I ran with temp. guages in the current locations (mid-way in the plastic elbow to the T-body, ambient measured from under the driver's side headlight, and I had another one INSIDE the home made hot-air intake, that never made it into the A'pexi intake when I did the FMIC.)
Findings were basically that once the engine was hot, on a hot day, intake temps never dropped below 50+F over abmient. The stock IC, once heatsoaked, stayed heated.
There was not much change to this when I tested the stock intake with the stock IC. At freeway speeds you cooled the intake charge FASTER, but not much lower. Low speed the intakes warmed up quicker without the stock type intake, but then again we still call them HOT AIR intakes, right?
I use Cyberdynne guages and temp. sensors. Fairly cheap, esp. when you have 4 of them in the glove box! Well, 3 hooked up right now, with a 4th seeing occasional duty as needed. My mount in the glove box only holds 3, and I don't have my carbon fiber yet to make it prettier.
07-18-02, 12:42 PM
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Originally posted by spyfish007
Do you realize that the stock sensor is plastic? I don't think it changes temp fast for a reason. Always is much faster going up than coming down.
Do you realize that the stock sensor is plastic? I don't think it changes temp fast for a reason. Always is much faster going up than coming down.
Going to need to test it when I can get in there. Maybe a block-off bolt, then use an upgraded sensor in the elbow.
07-18-02, 02:20 PM
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Originally posted by piston eater
Where is the PFC sensor mounted? Time to move mine ASAP!
Thanks!,
Manolis
Where is the PFC sensor mounted? Time to move mine ASAP!
Thanks!,
Manolis
07-19-02, 10:36 AM
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Yes, that is the best solution. But I'll have to take it out...or at least get to it to take the output readings. Unless anyone knows that?
07-23-02, 05:44 PM
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Does someone know the part number for the AIT? I ordered one from my Mazda dealer and they ended-up giving me the water temp sensor (good work guys)...thanks all 
07-23-02, 06:26 PM
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i replaced mine with one from a series 4 rx7. it is now in the elbow right before the throttle body. reacts much quicker and gives numbers which are much more believable than the crap the factory sensor was giving.
it uses a different voltage than the factory sensor and requires calibration of the ecu to compensate for this. most stand alones should be capable of this.
it uses a different voltage than the factory sensor and requires calibration of the ecu to compensate for this. most stand alones should be capable of this.
07-24-02, 12:36 AM
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Hey, thanks for the pic, at least it ruled out what I thought. Mazda gave me a sensor that is part # NF02-18-840 and says Sensor on the bag, but on the box it says Sensor, Water Temp and the sensor is gold and green (hence a water temp sensor)...damn, why is this so hard?...lol Someone must have the part #?!
07-24-02, 12:37 AM
#21
https://www.rx7club.com/forum/showth...ntake+air+temp
The guy in the 2nd to last post reported relocating his sensor awhiles back. I had though about finding a replacement needle probe sensor and somehow calibrate it to that of the stock sensor.
The guy in the 2nd to last post reported relocating his sensor awhiles back. I had though about finding a replacement needle probe sensor and somehow calibrate it to that of the stock sensor.
07-24-02, 12:38 AM
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Originally posted by daem0n
Hey, thanks for the pic, at least it ruled out what I thought. Mazda gave me a sensor that is part # NF02-18-840 and says Sensor on the bag, but on the box it says Sensor, Water Temp and the sensor is gold and green (hence a water temp sensor)...damn, why is this so hard?...lol Someone must have the part #?!
Hey, thanks for the pic, at least it ruled out what I thought. Mazda gave me a sensor that is part # NF02-18-840 and says Sensor on the bag, but on the box it says Sensor, Water Temp and the sensor is gold and green (hence a water temp sensor)...damn, why is this so hard?...lol Someone must have the part #?!
07-24-02, 12:40 AM
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hey, I don't mind waiting for the part # - I can't call until they open anyway. I imagine it is a similar price to this sensor - it cost me about $60....they better take it back since they told me it was the AIT...lol (Can we just find ONE competent dealer? :P)
07-24-02, 01:39 AM
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I just checked the parts catalogues online and I can't seem to see any sensor parts listed, maybe I'm just not looking in the right place - someone must have the part number for the Air Intake Thermosensor, no?