The shop manual states that the C6 cooling fan "on percentage" ranges from 10% to 90%, with 90% being considered hi or full speed. Is the 90% built into the fan module or pcm so that when tuning , 90% cannot be exceeded ? I noticed when data logging, that the percentages that I programmed run slightly lower indicated. At 85% programed for a given temp, indicated 76.5% , which coincidentally is 90% of 85%. So if you want the full 90% , do you need to program 100% to get it ? Any info would be appreciated. Thanks in advance..........
The shop manual states that the C6 cooling fan "on percentage" ranges from 10% to 90%, with 90% being considered hi or full speed. Is the 90% built into the fan module or pcm so that when tuning , 90% cannot be exceeded ? I noticed when data logging, that the percentages that I programmed run slightly lower indicated. At 85% programed for a given temp, indicated 76.5% , which coincidentally is 90% of 85%. So if you want the full 90% , do you need to program 100% to get it ? Any info would be appreciated. Thanks in advance..........
Anyone data logged and made a similar observation ?
I believe this is due to the design's max safe PWM duty cycle. The fan speed is basically controlled by a transistor switching on & off very quickly. The more time "on" the higher the fan speed, hence higher duty cycle. If you reached 100% the transistor would be on 100% of the time. I have not seen schematics of the internal driver & output circuits for our ECU's and haven't seen anyone say if this is really the max safe operating duty cycle or not, so I wouldn't exceed it unless someone knows for sure otherwise.
I believe this is due to the design's max safe PWM duty cycle. The fan speed is basically controlled by a transistor switching on & off very quickly. The more time "on" the higher the fan speed, hence higher duty cycle. If you reached 100% the transistor would be on 100% of the time. I have not seen schematics of the internal driver & output circuits for our ECU's and haven't seen anyone say if this is really the max safe operating duty cycle or not, so I wouldn't exceed it unless someone knows for sure otherwise.
I understand and agree about the 90% duty cycle for the fan module. Still curious about the program format ie what % programmed results in an actual 90% duty cycle at the fan. Mine seems to run aprox. 10% under. If I program 85% for a given temp., scanner indicates 76.5%. Wondering if that differential is built in to prevent exceeding the 90% .
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cooling fan percentages.........
