Quote:
Originally Posted by TheEnemy
bwilson, is the decrease after 85f due to more ac use, or is it something else?
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It was AC. When the humidity and temperatures approach each other, there is a serious health risk from a sleepy driver and heat prostration. I can do through the 80s and even 90s if it is dry and no direct sun (aka., I'm on the shady side.) But I don't like to get so hot that I become sluggish and inattentive.
When I have to use AC, I take the higher speed route as this reduces the relative AC contribution. Regardless of speed, the AC uses a fixed amount of power limited by the compressor, power drain. At slow speeds, the AC becomes the predominate load easily equaling the fuel burned to get the car to its destination. The mileage impact can easily double the fuel rate of burn at slow speeds. At higher speeds, the AC becomes a smaller fraction of the load so the mileage more closely approaches the highway mileage. Just make sure you're not going so fast that the engine has to go in especially fuelish power regions.
What I'll do is turnoff the AC compressor when stopped and let the fan recirculate the air and keep it off until I get back to speed. Then I enable the AC to bring the cabin back to tolerable. If coming to a stop, I'll turn off the AC so the ICE can stop while I slow down.
Bob Wilson