Radiator fan power draw on highway?

[Blacktree]

I'm surprised the ECU doesn't do this already. Even back in the 90s, GM cars had this functionality.

I remember playing with that in TunerPro, in a previous car. IIRC, it was set to turn off the fans at 55mph, from the factory. I dropped it to 40, and had no overheating issues. But that car had a front splitter and a hood vent (basically a race car). So the radiator got lots of airflow.

[EcoCivic]

Originally Posted by Blacktree

I'm surprised the ECU doesn't do this already. Even back in the 90s, GM cars had this functionality.

I remember playing with that in TunerPro, in a previous car. IIRC, it was set to turn off the fans at 55mph, from the factory. I dropped it to 40, and had no overheating issues. But that car had a front splitter and a hood vent (basically a race car). So the radiator got lots of airflow.

Yeah I'm surprised too, I can't imagine why Honda couldn't have done that also. Clearly they recognize the significance of electrical loads since they use the dual mode charging system to reduce the alternator voltage when full voltage isn't needed to save fuel. 10-20 amps of likely unnecessary load whenever the AC compressor is running seems like a pretty significant oversight, especially when it could be eliminated with a few lines of code.

My best guess for why they don't disable the fans at higher speeds is because they just didn't think doing the testing to see what speed the fans are no longer needed at while accounting for conditions like possible crosswinds and tailwinds was worth it.

The ECU can't monitor AC refrigerant pressure to ensure the condenser is being cooled adequately, so Honda would have to be darn sure that whatever speed the ECU was set to disable the fans at would work properly in all conditions.