hot/cold weather = rich/lean??
05-15-2006, 02:15 AM
#1
hot/cold weather = rich/lean?? I think I've noticed the hotter it gets the leaner the wideband reads, does this sound right?, I'm in the desert now and its getting into the tripple digits, I'm trying to put a summertime tune on the car and was wondering if there's a % that the afr will usually read between hot or cool day's... so I'z can figure out what kinda changes I can expect between 105 day and 85 at night...
05-15-2006, 06:21 PM
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Hot is leaner
Cold is richer.
You can get PE mode to correct for temp. But with the rest its part of the VE table calculation. EFIlive has added extra tables in their custom operating system to help with this.
Cold is richer.
You can get PE mode to correct for temp. But with the rest its part of the VE table calculation. EFIlive has added extra tables in their custom operating system to help with this.
05-15-2006, 06:25 PM
#3
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Yeah, we have a table called Charge Temperature Blending:
I haven't played around with this one too much, but it might be a source to correct the issue.
The PCM calculates the charge temperature (in degrees Kelvin) using the following formula
273.15+IAT+((ECT-IAT)*factor) where factor is obtained from this calibration.
At low airflow "factor" is closer to 1 which weights the charge temperature in favour of ECT.
At high airflow (>150g/s) "factor" is closer to 0 which weights the charge temperature in favour of IAT.
The theory being that heat (ECT) is transferred from the heads and manifold after the IAT has been measured and prior to the air entering the cylinder.
If factor is 0, then the charge temperature will be IAT, if factor is 1, then the charge temperature will be ECT, other values for factor will blend the charge temperature between IAT and ECT accordingly.
273.15+IAT+((ECT-IAT)*factor) where factor is obtained from this calibration.
At low airflow "factor" is closer to 1 which weights the charge temperature in favour of ECT.
At high airflow (>150g/s) "factor" is closer to 0 which weights the charge temperature in favour of IAT.
The theory being that heat (ECT) is transferred from the heads and manifold after the IAT has been measured and prior to the air entering the cylinder.
If factor is 0, then the charge temperature will be IAT, if factor is 1, then the charge temperature will be ECT, other values for factor will blend the charge temperature between IAT and ECT accordingly.
