Hi, have been logging the iat on my m8 and and I am a little unsure why on a dead cold motor on 26 c day my inlet air temp reads 39c to 40c and once hot and running on the same 26c day it reads 50c to 53c . the thermometer is just inside the throttle blade and I cant see the air warming up that much in such a short distance . if anyone can explain I would appreciate it. Max
Warmed up the throttle body and the sensor itself is warmer from engine heat. Intake air also is drawn around the heat of the engine.
Quote from: To The Max on January 25, 2019, 04:48:32 PM
Hi, have been logging the iat on my m8 and and I am a little unsure why on a dead cold motor on 26 c day my inlet air temp reads 39c to 40c and once hot and running on the same 26c day it reads 50c to 53c . the thermometer is just inside the throttle blade and I cant see the air warming up that much in such a short distance . if anyone can explain I would appreciate it. Max
On a dead cold motor as in sitting overnight, it should read very close to ambient. At least my TC and now current v rod does. Running and up to temp it will run a bit hotter then ambient. Heat conduction of the IAT body itself from air blowing past the throttle body from the front head, well the heated IAT body over powers the probe some to give an above ambient reading.
Ron
Quote from: rbabos on January 25, 2019, 06:25:00 PM
Quote from: To The Max on January 25, 2019, 04:48:32 PM
Hi, have been logging the iat on my m8 and and I am a little unsure why on a dead cold motor on 26 c day my inlet air temp reads 39c to 40c and once hot and running on the same 26c day it reads 50c to 53c . the thermometer is just inside the throttle blade and I cant see the air warming up that much in such a short distance . if anyone can explain I would appreciate it. Max
On a dead cold motor as in sitting overnight, it should read very close to ambient. At least my TC and now current v rod does. Running and up to temp it will run a bit hotter then ambient. Heat conduction of the IAT body itself from air blowing past the throttle body from the front head, well the heated IAT body over powers the probe some to give an above ambient reading.
Ron
Ron I tend to agree with you that from a dead cold start that it should read close to ambient so it isn't . I have been told that on some ecu set ups that the temp reading is a prediction of air temp going past the valve and im wondering if this might be the case here ? Max
A faulty air temp sensor?
Quote from: To The Max on January 26, 2019, 02:28:58 AM
Quote from: rbabos on January 25, 2019, 06:25:00 PM
Quote from: To The Max on January 25, 2019, 04:48:32 PM
Hi, have been logging the iat on my m8 and and I am a little unsure why on a dead cold motor on 26 c day my inlet air temp reads 39c to 40c and once hot and running on the same 26c day it reads 50c to 53c . the thermometer is just inside the throttle blade and I cant see the air warming up that much in such a short distance . if anyone can explain I would appreciate it. Max
On a dead cold motor as in sitting overnight, it should read very close to ambient. At least my TC and now current v rod does. Running and up to temp it will run a bit hotter then ambient. Heat conduction of the IAT body itself from air blowing past the throttle body from the front head, well the heated IAT body over powers the probe some to give an above ambient reading.
Ron
Ron I tend to agree with you that from a dead cold start that it should read close to ambient so it isn't . I have been told that on some ecu set ups that the temp reading is a prediction of air temp going past the valve and im wondering if this might be the case here ? Max
Sounds a little hokus pokus to me. Why not just use actual temp rather then predicting? I'd compare notes with others on the cold engine ambient reading and go from there. Then you know if it's by design or the sensor resistance is off.
Ron
Ron, good suggestion I have 3 m8's I can do that with . will get back soon with the results. Max
Checked out two other soft tails and a cvo SG all the same stone cold about 26 deg c ambient air temp P.V. reads 38 deg c , must be the way they are set but why. any smart people out there that might know why. Max
Quote from: To The Max on January 29, 2019, 04:59:02 AM
Checked out two other soft tails and a cvo SG all the same stone cold about 26 deg c ambient air temp P.V. reads 38 deg c , must be the way they are set but why. any smart people out there that might know why. Max
Sensor built by the cheapest bidder. LOL. In reality as long as they are all the same, a tune would be based on those temp numbers anyway so it should work out. As for the of 12* error, I doubt it's intentional or design. More likely the sensor values or in how the PV reads it. In my bike for example the bat volts reads .3-.4 lower then actual. On other bikes I've helped tune of the same model the PV reads the correct voltage. No logical explanation for it and no ill effects as long one knows about it and tests actual voltage with a VOM at the battery. On the other hand both my coolant temp and IAT match up within 2* on a cold engine. What does your head temp read when cold?
Ron
The intake air temp is probably not the actual temp. Like the calculated head temps in the Twin Cam. By the time the tuning device sees the number it has been rehashed by some math function done in the background.
Just my guess, it reality I dont know :turd: !