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Old 06-04-2022, 03:13 AM   #81 (permalink)
Drifter
EcoModding Apprentice
 
Join Date: Apr 2022
Location: California
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Cx9 - '18 Mazda CX9 Grand Touring
90 day: 31.41 mpg (US)

Prius - '10 Toyota Prius III
90 day: 57.8 mpg (US)

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Quote:
Originally Posted by Drifter View Post
I would hope so - or that the heat is the last resort. If you have multi-zone A/C I don't see any other way than using the heat for the sections with higher temperatures.

I look forward to testing it this summer...

I tried to do some testing on a long drive yesterday, but there is a lot of variation just keeping the A/C on the same setting. According to the scangauge, my AC watts were 2,000 when first starting the car after it was parked in the sun for an hour. After a mile or two A/C watts dropped to 1600, then 1100, and eventually 600-800.

ECO mode seemed to immediately lower A/C watts by 50-100 when driving steady state. The inverse was also true - turning off ECO mode caused A/C watts jump 50-100... I also never saw more than 1600 watts in ECO mode when first starting after parking, so that hot car start may be where the ECO setting makes the most difference (~400 watts). The downside is ECO mode does not cool a sweltering car down nearly as well.

Steady state driving 55mph in the bright sun with 91 degree outside air temperatures took 600-800 watts to keep me comfortable. Turning the A/C off and putting all 4 windows down 1/2 way seemed to add 0.5-1.5 horsepower (~400-1100 watts). I wasn't as comfortable, both temperature and noise, and without a clear efficiency advantage I think I'd just run A/C instead.

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