Fuel Economy and AC

on most cars, Max A/C does 2 things. it speeds up the fan, and it closes the vent that normally mixes in some outside air.

maybe on the prius it only stops the air mixture, doesn't speed up the fan? i'm just guessing, becuase i DON'T HAVE A DARN PRIUS YET!!! :|

 

I settled on 72 degrees for my 'normal' AC setting, and adjust it down if I'm warm. SEEMS like less engine (ICE) use than before...

 

In SoCal it is very hot now, so I have the AC on the second setting and close off the passenger side air vents so I get full power on me. So that way I don't need to cool the car, just me. I think that the fuel economy will not be too much effected because of the heat, to keep it warm.

 

If your car is warm and you push AutoAC, it should kick the fan in high even if you set it low before. You can then override that if you want, by choosing a lower fan setting manually. Also, if you turn on AutoAC and then increase your temp setting, the fan should slow down as well (not 71... Keep increasing it to 80 or more to prove that this works).

If you're running with high AC all the time, that would certainly account for the poor mileage, but it might just be because you're running with a high fan and a low temp all the time. Instead of using the auto mode, just turn on the AC yourself, put the fan on the lowest setting, make sure the air is recycling (instead of coming from the outside) and choose a reasonable temp (70-72, say). Shouldn't impact your mileage that much at that point.. My car stays cool in moderate heat with over 50mpg city...

 

Aside from all of the A/C discussion, since getting your Prius have you modified your driving habits in an effort to strive for higher gas mileage? Things like coasting to a stoplight, minimizing jackrabbit starts and monitoring the power output on the MFD to try to use the engine as little as possible in your driving would help in your quest to improve gas mileage.

 

I've been wondering.

Has anyone had a co-pilot take note of computer reported MPG during acceleration, and seen where easing up to speed at 17MPG (normal for me, espciallly up the hills around here) is ACTUALLY better than jackrabbiting at 7MPG for a shorter time? It would be interesting to see if a shorter acceleration period is actually 'wasting' gas...

 

I believe the general consensus is that accelerating rapidly (but safely) to near cruising speed is the BEST way to do it. However, don't accelerate so hard you need to hit the brakes a few seconds later. Engines are more efficient when you give them more to do.

 

I can't help you understand your "low" gas mileage, but I am also sitting at around 40 mpg consistently. Granted I only have 1,500 miles on the car. I live in a hilly area and most of my trips are short (5 miles). I'm also using the AC most of the time (set at 72). I'm hoping that maybe I'll get better mileage as the car breaks in better.

I love, love, love my prius (white #9), but am a little dissappointed in the mpg. Good grief, how could 40 mpg be dissappointing...spoiled brat!

 

But would a 'jackrabbit start' be the right way to describe that?

0 to 35 in how many seconds would be 'rapidly' but not wasteful?...

 

Short trips kill the fuel economy---don't expect high numbers with 5 to 8 mile commutes. On the classic never use the A/C max setting. As has been stated before, it forces the ICE to run. Open the windows, cool off the car and then back to A/C auto. Also be sure to check your tire pressures and run them near max inflation pressure--like 44/42 on the classic. Always ran mine there and got great economy and not adverse tire wear.