Hot climates & AC & Gas mileage

[mohammad]

Compressor efficiency was not my point.

To quote you

Question: Isn't the A.C. / compressor disconnected from the drivetrain in the Prius? If so, this would be the reason it doesn't drop ... or drop so much on the Prius.

by drop aren't you talking about a reduction in MPG? isnt this 100% related to compressor efficency?

[7milesout]

Yes. No.

[TheLandYacht]

Question: Isn't the A.C. / compressor disconnected from the drivetrain in the Prius? If so, this would be the reason it doesn't drop ... or drop so much on the Prius.

Exactly right, electric compressor.

[TheLandYacht]

Well, overall fuel efficiency wasn't really my question. I was just surprised that AC took such a huge hit, when no other vehicle I've ever driven has (noticeably).

I've driven, of note...
Prius
Ford F150
Ford Econoline van
Dodge Sprinter van (tall roof)
Dodge caravan (various through the years)
Various ford & chevy 4-door sedans throughout the years.

The last 4 entries were because I spent 25 years behind the wheel in Austin as a taxi driver. So I'm intimately familiar with what AC does to fuel economy.

BTW, finally got the chance to get a good look at my fuel-fill-up numbers from Fuelly. Care to guess which weeks I was using AC the most? All of this was with driving style & route almost identical. 40 miles to&from over 60-70mph highways on rolling hills all the way...cruise set religiously as soon as I hit a speed I could do so.



Overall, I'm hovering at 36.8 MPG

[7milesout]

Well, not only are we playing with only 74 or 78 hp, so that whatever amount of hp required by the A.C. is a larger percentage of the available power than probably any vehicle we all have ever driven ... BUT ALSO, I'm betting the Mitsubishi engineers, when deciding which A.C. compressor, looked through the vendor's catalog of compressors, and said, "show me the smallest ones, and out of those, which one is the least expensive?"

And then they said, "if we have you remove this noise isolation feature, how much cheaper is it?" Followed by, "and take out anything technology based that may reduce drag performance ... how much is it now?" Followed by, "I'll take it!"

[Top_Fuel]

...whatever amount of hp required by the A.C. is a larger percentage of the available power...

Exactly. How did a Geo Metro or 1970's vintage VW Beetle power an AC compressor?!? Those cars must have been a bear to drive with the AC running.

[Dookaughs]

And then they said, "if we have you remove this noise isolation feature, how much cheaper is it?" Followed by, "and take out anything technology based that may reduce drag performance ... how much is it now?" Followed by, "I'll take it!"

Mitsubishi owners click on the AC and it sounds like sprung a door stop.

[7milesout]

Yeah, mine is really loud. One of my sons, he just seems less technically in touch than the other 2. Yet, he studies his butt off and gets really good grades in engineering classes. However, I let him use the Mirage not long ago and I went back and checked the dash cam. He rode down the road with the windows down and the A/C on. I could hear the A/C compressor on the dash cam because it is so loud. Using the A/C with the windows down is ILLOGICAL and WASTEFUL. He didn't know he had the A/C on.

He also, got frustrated from missing a turn at one point and was somewhat abusive to the car due to his frustration. I didn't call him on it because I didn't want him to know I was spying on him. However, I'm now hesitant to let him use my Mirage again.