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Old 05-20-2021, 11:34 PM   #46 (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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Quote:
Originally Posted by EcoCivic View Post
Thanks for sharing. I never would have thought a fan failure would make such a difference going 45 MPH, especially on such a cool day. Everything I could find says that electric radiator fans are typically outflowed by ram air at speeds of over somewhere between 20 and 40 MPH, although obviously this would depend on the design of the vehicle and how powerful the fans are, so the only way to know for sure is to test it.

I think one of the biggest factor is how well the radiator is ducted in. A radiator with large gaps around it that allow a significant amount of ram air to go over or around the rad rather than through it like how my car came would surely rely a bit more on the fans than a vehicle with a radiator that's properly ducted to the grill so all air is forced through the rad and can not bypass it like how my radiator is now. Ever since I ducted my radiator, I noticed that the fans don't seem to run as much in traffic.
This was an 1984 model, so not very well ducted. Plus who knows how many times the radiator had been flushed, or the effects of the fins getting bent over the years. Add to that the 12,000ft altitude and lack of air to cool. All that plus floored and wound up for several minutes, plus the fact I was going slower than 45mph at the very top, the place where it got even closer to the red line. But at any rate, I didn't have any overheating problems as long as the fan was working properly.
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EcoCivic (06-07-2021)