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Old 05-20-2021, 07:54 PM   #44 (permalink)
Isaac Zachary
High Altitude Hybrid
Join Date: Dec 2020
Location: Gunnison, CO
Posts: 1,320

Avalon - '13 Toyota Avalon HV
90 day: 40.45 mpg (US)

Prius - '06 Toyota Prius
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Originally Posted by EcoCivic View Post
Good thoughts. I'm not sure that running the fans on the highway would help if the engine is running hot. When I had my thermostat out a couple years ago, I experimented a couple times with turning the fans on while driving down the highway at speeds I don't remember, probably around 60 MPH. Whether the fans were powered or not really didn't seem to make any difference to the coolant temp, perhaps because I have my radiator ducted in so any air that passes through the grill is forced through the rad and can't escape around it. However, I now have a different fan setup with a custom shroud, so I may test at what speed running the fans no longer helps cooling anymore as I have wondered about that too.

There isn't really any practical way for me to significantly improve the alternator's efficiency, so not using it where possible and reducing the load on it when I do need to use it is the next best thing I can do. It seems that since the fans are one of the largest power draws on the car, not running them when there is no benefit to doing so would be a good way to accomplish the goal of reducing the amount of power the alternator wastes.
I've noticed cooling fans playing an effect going up a steep mountain pass at highway speeds, at lest at speeds up to 45mph. I couldn't really go much faster in my Golf diesel, the last car I had the fan go out while driving up a mountain pass. I kept going, it was about 50-60F outside, and the needle got a bit too close for comfort to the red line by the time I got to the top of the pass.

When the fan got covered by loose firewall material on the Super Beetle going up a hill at 65mph that made for a quick engine failure.
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The Following 2 Users Say Thank You to Isaac Zachary For This Useful Post:
aerohead (05-21-2021), EcoCivic (05-20-2021)