what is your favorite way to pull timing?
05-23-2011, 08:29 AM
#21
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I replaced the IAT thermistor with a several different fixed resistors and recorded the indicated temperature with HPTuners Scanner. Here are my results:
Ohms Temp C
198.....97
297.....85
326.....81
490.....70
8740....0
I use a 300 ohm resistor.
Ohms Temp C
198.....97
297.....85
326.....81
490.....70
8740....0
I use a 300 ohm resistor.
05-23-2011, 09:30 AM
#22
05-23-2011, 08:14 PM
#23
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The resistor determines what part of the IAT table is used for nitrous. You want to choose a value that corresponds to a temperature not seen during normal driving. A 300 ohm resistor makes the GM 411 PCM think the IAT is 85 degrees C. I use the cells above 80C for nitrous tuning. The IAT sensor (Thermistor) is highly non-linear and I do not know what temp corresponds to 750 ohms. I do know 490 ohms corresponds to 70C (158F) which I have seen when creeping along in summer traffic. Higher resistance corresponds to lower temps so I would say any value greater than 490 ohms is a poor choice. I too apologize to OP for thread hijack. I think I'm done.
05-23-2011, 08:35 PM
#24
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EFI Live here with a re-flash. Heck after i flash the tune I then go back and pull it out just to be safe that it flashed 100%. I guess I'm just **** like that... Personally, I would not trust anything that I couldn't verify via data log or some type real time reading.
05-24-2011, 05:48 PM
#26
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You can verify the resistor mod using data logging or even an IAT gauge. I'm getting a programmable AeroForce that reads ODBII data so it will display my AFR and IAT.
