aldive
Elite In Memoriam
- Joined
- January 17, 2001
- Messages
- 24,569
- Reaction score
- 30
- Year, Model & Trim Level
- 1999 XLT
Having previously conducted experiments on the effect of vehicle speed on IAT ( http://www.explorerforum.com/forums/showthread.php?t=143720&page=1&pp=20 )
I decided to evaluate under hood temperature at various speeds, during in town driving, stopped in Park ( with the hood closed and with it open ).
For the under hood temperature measurements, I used a Radio Shack Wireless Indoor/Outdoor Thermometer with Remote Sensor ( http://www.radioshack.com/product.a...10_005_001_000&product_id=63-1087&site=search ).
The test parameters were as follows: various truck speeds from 20 to 70 MPH, determined by GPS ( Dead Link Removed ), ambient temperature determined by the vehicle’s outside temperature display, IAT from PCM as reported to OBD II scanner ( http://www.autoxray.com/default.htm ).
The truck was driven for 10 minutes at each speed on cruise control and then the under hood temperature was noted and recorded.
For all of the trials, the Black Magic Extreme 180 electric fan ( Dead Link Removed ) was on continuously via manual control.
Prior to any of the tests, the engine was warmed up and the coolant temperature was 194 F ( OBD II scanner determined [ http://www.autoxray.com/default.htm ] ).
Since its use will be a temporary, permanent mounting was not needed. Various under hood locations were tried and the readings were basically the same.
Speed ambient temperatureUnder hood temperature IAT
20 91 104 96
30 91 104 95
40 91 102 94
50 91 100 93
60 91 99 93
70 92 98 91
Traffic 93 124 132
Driving
Idle 92 157 187
Hood closed
Idle 93 134 153
Hood open
It appears that under hood temperature is directly related to air flow, either by vehicle speed or by an open hood. The difference in under hood temperature and IAT at 70 MPH is only 7 F, and the under hood temperature is only 6 F warmer than ambient.
I decided to evaluate under hood temperature at various speeds, during in town driving, stopped in Park ( with the hood closed and with it open ).
For the under hood temperature measurements, I used a Radio Shack Wireless Indoor/Outdoor Thermometer with Remote Sensor ( http://www.radioshack.com/product.a...10_005_001_000&product_id=63-1087&site=search ).
The test parameters were as follows: various truck speeds from 20 to 70 MPH, determined by GPS ( Dead Link Removed ), ambient temperature determined by the vehicle’s outside temperature display, IAT from PCM as reported to OBD II scanner ( http://www.autoxray.com/default.htm ).
The truck was driven for 10 minutes at each speed on cruise control and then the under hood temperature was noted and recorded.
For all of the trials, the Black Magic Extreme 180 electric fan ( Dead Link Removed ) was on continuously via manual control.
Prior to any of the tests, the engine was warmed up and the coolant temperature was 194 F ( OBD II scanner determined [ http://www.autoxray.com/default.htm ] ).
Since its use will be a temporary, permanent mounting was not needed. Various under hood locations were tried and the readings were basically the same.
Speed ambient temperatureUnder hood temperature IAT
20 91 104 96
30 91 104 95
40 91 102 94
50 91 100 93
60 91 99 93
70 92 98 91
Traffic 93 124 132
Driving
Idle 92 157 187
Hood closed
Idle 93 134 153
Hood open
It appears that under hood temperature is directly related to air flow, either by vehicle speed or by an open hood. The difference in under hood temperature and IAT at 70 MPH is only 7 F, and the under hood temperature is only 6 F warmer than ambient.
