like i have said before in a couple posts, i live down in HOT, and HUMID South Florida, Fort Lauderdale actually.
starting in March and lasting all the way till September, and November...the heat and humidity can get unbearable at times.
therefore i am running my A/C in my Fit on full blast, all the time.
sometime's when it is cloudy, i get the car cooled down, then every 5 minutes or so, i turn the air off but leave the fan running at full blast...then 10 minutes later i turn the A/C back on... and i repeat that until i get to where i am going... i know that sounds silly, but over time i am sure it saves a little bit of gas.

i have heard that instead of turning the fan all the way up to Max (1-4) 4 being the Max, you can save gas by turning the fan down to 3 or even 2 if possible..is there any truth to this?

and there is also this "Fuel Doctor" product that you plug into your cigarette lighter...this is what it is suppose to do


Fuel Doctor's FD-47 increases a vehicle’s miles per gallon (MPG) through power conditioning of the vehicle’s electrical systems. Conditioned and clean power allows the vehicle’s electronic control unit (ECU), fuel injection and engine timing equipment to operate more efficiently. When the vehicles engine runs more efficiently it will require less fuel, produce more power and have reduced exhaust emissions (reduced CO2). As a vehicle matures, the power systems tend to generate and experience more electrical noise or electrical interference. This noise can have many detrimental effects on the vehicle’s systems and decrease their efficiency. The FD-47 simply plugs into the lighter socket/power port and the power conditioning qualities of the FD-47 help to reduce and remove this noise and to restore your vehicle’s efficiency.


i also think that Honda needs to find a way to run the A/C independent of the engine somehow..because down here in south florida, people in their new insights and fit's are not getting the mileage they expected because of high A/C usage..
COME ON HONDA!! YOU HAVE SOME OF THE BEST ENGINEER'S IN THE WORLD..YOU CAN COME UP WITH THIS!

 

Would you believe a product that you plug into a wall outlet to decrease your monthly power bill? Didn't think so. Snake oil.

As far as running the A/C seperately from the engine, it could work. I don't know that it would save any power though. You could have an electric motor to run the compressor, much like in a stand-alone home air-conditioner. You would, of course, need to power this with electricity... which would come from the alternator... which would be placing a greater load on the engine to supply the power to the compressor.

Somehow I doubt that the A/C would be more efficient if the energy to run it were being converted into an electrical charge, and then converted back to kinetic energy, with the inefficiencies of both an alternator and motor, than just powering the alternator straight from the serpentine belt.

Here's a little trick though. When you're in city traffic, only turn on the A/C when decellerating. Because the compressor places extra drag on the engine, it will help slow the car, much like engine braking. If you are moving at 40 mph, and have to slow to a stop, just using the brakes converts that kinetic energy to heat energy, which is radiated from the rotors. If you use pure engine braking, you are converting it to heat energy within the engine block itself, which is released through the radiator and exhaust. Why not use a bit of that potential to power the air compressor, and then cut it off while moving forward unless absolutely necessary?

(As a Floridian by birth, who lived in Florida for 20 years, I'm much more inclined to say F--- the extra mileage, and run the A/C on max. Florida's climate is too damn oppressive for playing games!)

 

check out this link from their website concerning certified test results..they are from a couple of testing agencies.
Technical | Fuel Doctor FD-47 Fuel Efficiency Booster - Improves Firing, Increases Power, Reduces Emissions

yeah, there is NO way i can run the A/C only on decelerating down here in Fort Lauderdale...growing up here, you know that even during the winter months the A/C is used ..except this past winter.
from December to February, there were more days in the lower 70's and upper 60's than days in the upper 70's which i normal...AND we set a record for 3 nights that were 40 degrees. in the morning, i would run down to the car and blast the heat, run back up into my apt. for at least 10 minutes. you would think the way i was asking that it was below 0! i use to live in Chicago so you would think i would be use to the cold...but i have been here since 2001...
anyways more about the A/C
i heard that when you are on the highway going faster than 55 mph, using the air then uses less gas because something about the RPM's being higher.
does anyone use air in their Fit and put the fan on 3 instead of 4 (Max)? does the fan speed matter at all?

 

Yeah, I remember the misery. Of course, I'm from Tallahassee, so it only lasts 8 months of the year instead of 11!

I live in Monterey now, on the central Cali coast - the average summer high/low is 70/55. In the winter, it's 60/45. My car's a/c gets used infrequently. My apartment has no a/c.

 

First, operating your A/C intermittently is costing you, not helping. Once you get the car cooled down, it takes much less energy to keep it down than to recool the car after it reheats. A lot less.
Unless you drive with your windows open.
Second, there are already A/C's independent of the engine, all electrical systems. Unfortunately the energy required to run the A/C compressor motor and all takes just as much energy and thus your alternator will eat up the hp just as readily as the belt. But you could run the A/C on batteries and recharge the batteries overnight. Call it a hybrid A/C.
But there is no free lunch. Especially with additives that promise real mpg improvement. Only 20 weight synthetic oil really helps. Power conditioning electrical systems? Gobblygook par excellence, for the unwashed.

 

In a nicer car with an automated climate control system and a thermostat, this might be true, but in a cheapie car like the fit with just a hot/cold knob, it doesn't matter. If the air compressor is running, it's running. If it's off, it's off. If you have the A/C running, it doesn't matter what you do. Switch to recirculate, change the fan speed, it runs the same. Turning the temperature selection knob just changes the amount of hot air that bleeds from the heater core.

So, even just cutting the A/C off while accelerating should be a big help, removing the extra strain on the engine at the point when it is least efficient. Some cars used to automatically shut off the compressor when you were accelerating, but I don't know if this is still the norm.

And then your home power bill goes up. Yup, no free lunch.

Agreed 100%. Automakers look for every possible way to squeeze more mileage out of their cars without compromising drivability, because that raises their CAFE and they can sell more profitable gas-guzzlers. Regarding the OP and the FD-47 stuff... do you really think a major development in fuel economy would be sold via the ShamWow route?

 

Don't kid yourself: auto manufacturers have spent a lot of time dealing with those issues What you see is what they got.
cheers

 

I get so tired of hearing people bitching about the Fit's A/C. Atlanta in the summer is neither bone dry nor cool, but as long as I park in the shade, the car cools down pretty quickly, and maintains an acceptable temperature at fan speed 1 or 2. I have never noticed any dimming of the lights, or performance difference as the compressor cycles on/off. Gas mileage is slightly better in June's heat than it was in January's cold.

I still plan to get the windows tinted, but overall, the Fit's A/C is comparable with the A/C in every car I have owned since 1978 (which was my first air conditioned car).