Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-29-2008, 12:20 PM   #1 (permalink)
EcoModding Lurker
 
Join Date: Apr 2008
Location: Colchester, CT
Posts: 38

POS - '97 Ford Aspire
90 day: 47 mpg (US)
Thanks: 0
Thanked 1 Time in 1 Post
windows vs. A/C

As the weather warms up, I'll need more than my vents to keep from frying while i drive. Is fuel economy better w/ the windows down (increased drag) or w/ A/C on (increased engine load)? I don't have the $$$ to get a scangage II yet to test myself. I drive a 97 ford aspire 5spd . THANKS!

__________________
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-29-2008, 12:27 PM   #2 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,770

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 53.56 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 66.29 mpg (US)
Thanks: 3,481
Thanked 6,281 Times in 3,250 Posts
In city driving, windows down generally trumps A/C use.

At higher speeds, the difference may depend more on the vehicle and the speeds you drive, I'd bet that for your vehicle, windows partly down is still best.

See this thread for more information:
http://ecomodder.com/forum/showthread.php?t=190
__________________
Latest mods: 3-cylinder Mitsubishi Mirage. EcoMods now in progress...
Ecodriving test:
Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 04-29-2008, 11:29 PM   #3 (permalink)
Giant Moving Eco-Wall
 
DifferentPointofView's Avatar
 
Join Date: Dec 2007
Location: The Dale, IL (or A-Dale)
Posts: 1,120

The Jeep! - '95 Jeep Grand Cherokee ZJ Laredo
90 day: 23.75 mpg (US)

The Caliber - '07 Dodge Caliber R/T
90 day: 30.6 mpg (US)

The 'Scort - '98 Ford Escort LX
Thanks: 0
Thanked 7 Times in 6 Posts
I took in account that I drive a brick, and big engines don't take such a big hit in MPG's from extra accesories because the amount of load put on it isn't very burdensome to the engine, whereas a small engine takes the burden more seriously.

So in the city, I drive with either vents on, or windows down.

On the highway, this is what I do. I don't see why more people don't do this, because it has shown me excellent results. Instead of running the a/c the whole time, I have the vents on, and when I get too hot, I press the A/C button, wait till the compressor has cycled twice, then turn off the a/c and use the vent again. The air remains cold for about 3 miles, and then goes back down to regular vent temps. I can usually stand it for about another mile, then i get hot (it's a good thing I'm cold all the time anyway ) then I let it cycle on twice, and turn it off.

My drive is about 10-12 miles, so I only have to press the a/c button three times. a whole lot better than driving 10 miles with the A/C constantly cycling on and off.

I judge when it cycles on by the volt gauge, because when the volts go down about 1-2 volts, (from about 14) that's when the compressor is running.

When on the highway, I never have the windows down. brick+open windows=giant brick parachute.
__________________


Yea.. I drive a Jeep and I'm on a fuel economy site, but you just wouldn't understand... "It's a Jeep thing!" *Jeep Wave*

Did I Use Too Many Abbreviations? Here's The Abbreviations List
  Reply With Quote
Old 04-30-2008, 01:14 AM   #4 (permalink)
Future EV Owner
 
Join Date: Mar 2008
Location: Sussex Wisconsin
Posts: 674

Wannabe - '05 Honda Civic LX
90 day: 40.53 mpg (US)
Thanks: 0
Thanked 4 Times in 4 Posts
I do the same thing. Off, on, off, on.
__________________
  Reply With Quote
Old 04-30-2008, 01:18 AM   #5 (permalink)
I'd rather be biking
 
boxchain's Avatar
 
Join Date: Feb 2008
Location: New Orleans, LA, US Minor Outlying Islands
Posts: 127

Lexie - '98 Honda Civic LX
90 day: 39.46 mpg (US)

Beater Hauler - '92 Isuzu Pickup

Rentaclipse - '08 Mitsubishi Eclipse ?
90 day: 28.28 mpg (US)

Fahrt - '83 BMW R80 ST
Thanks: 0
Thanked 4 Times in 4 Posts
You can switch the AC on during in gear accelerations, taking advantage of DFCO. See: http://forum.ecomodder.com/showthread.php?t=1447

Works best for stop/go type travels. I've found a 5-10s decel will cool the air down for about a minute. It's free and better than nothing
__________________

My bike runs on dihydrogen monoxide.
I like to use these acronyms
  Reply With Quote
Old 04-30-2008, 06:52 PM   #6 (permalink)
Legend in my own mind
 
trikkonceptz's Avatar
 
Join Date: Apr 2008
Location: Homestead, Fl.
Posts: 927

Evil Pumpkin - '08 Scion xD RS 1.0 #1633
90 day: 35.45 mpg (US)

Silent Silver Killer - '10 Honda Insight EX
90 day: 51.5 mpg (US)
Thanks: 2
Thanked 13 Times in 12 Posts
I started doing this also and quickly realized something .... it would be awesome if we could run a/c without the fan. In vent mode as mentioned the a/c remains cold for a while before it become hot, yet you can't activate the a/c without the fan.

They should invent an a/c mode that work with the fresh air vent so when cruising you shouldn't have to use the fan ...
__________________
Thx NoCO2; "The biggest FE mod you can make is to adjust the nut behind the wheel"

I am a precisional instrument of speed and aeromatics
If your knees bent in the opposite direction......what would a chair look like???





  Reply With Quote
Old 04-30-2008, 08:44 PM   #7 (permalink)
I'd rather be biking
 
boxchain's Avatar
 
Join Date: Feb 2008
Location: New Orleans, LA, US Minor Outlying Islands
Posts: 127

Lexie - '98 Honda Civic LX
90 day: 39.46 mpg (US)

Beater Hauler - '92 Isuzu Pickup

Rentaclipse - '08 Mitsubishi Eclipse ?
90 day: 28.28 mpg (US)

Fahrt - '83 BMW R80 ST
Thanks: 0
Thanked 4 Times in 4 Posts
Quote:
Originally Posted by trikkonceptz View Post
They should invent an a/c mode that work with the fresh air vent so when cruising you shouldn't have to use the fan ...
You don't want that, it's the same as running AC in your house with the windows open, you'll just pull in more hot humid air, making the AC work less effectively.
__________________

My bike runs on dihydrogen monoxide.
I like to use these acronyms
  Reply With Quote
Old 04-30-2008, 10:47 PM   #8 (permalink)
Giant Moving Eco-Wall
 
DifferentPointofView's Avatar
 
Join Date: Dec 2007
Location: The Dale, IL (or A-Dale)
Posts: 1,120

The Jeep! - '95 Jeep Grand Cherokee ZJ Laredo
90 day: 23.75 mpg (US)

The Caliber - '07 Dodge Caliber R/T
90 day: 30.6 mpg (US)

The 'Scort - '98 Ford Escort LX
Thanks: 0
Thanked 7 Times in 6 Posts
Quote:
You can switch the AC on during in gear accelerations, taking advantage of DFCO. See:
I've found that when I do that, it isn't good, the volts drop down, and when they do I have less pickup and use more gas. the Jeep also shakes from lack of sparking power. I get the best mpg's when I'm running almost 15 volts. and at night my dash lights are brighter
__________________


Yea.. I drive a Jeep and I'm on a fuel economy site, but you just wouldn't understand... "It's a Jeep thing!" *Jeep Wave*

Did I Use Too Many Abbreviations? Here's The Abbreviations List
  Reply With Quote
Old 05-01-2008, 12:59 AM   #9 (permalink)
I'd rather be biking
 
boxchain's Avatar
 
Join Date: Feb 2008
Location: New Orleans, LA, US Minor Outlying Islands
Posts: 127

Lexie - '98 Honda Civic LX
90 day: 39.46 mpg (US)

Beater Hauler - '92 Isuzu Pickup

Rentaclipse - '08 Mitsubishi Eclipse ?
90 day: 28.28 mpg (US)

Fahrt - '83 BMW R80 ST
Thanks: 0
Thanked 4 Times in 4 Posts
Guh, I meant decelerations.
__________________

My bike runs on dihydrogen monoxide.
I like to use these acronyms
  Reply With Quote
Old 05-01-2008, 08:39 PM   #10 (permalink)
EcoMudder
 
Harpo's Avatar
 
Join Date: Mar 2008
Location: Gainesville, FL
Posts: 79

Harpo's Honda - '05 Honda Civic VP
90 day: 42.64 mpg (US)
Thanks: 0
Thanked 2 Times in 2 Posts
Both work well

I got my windows tinted (FormulaOne Pinnacle 35) and it makes a bunch of diffence on how much you have to touch the compressor button. I still use almost exclusively DFCO AC because with my city driving. The DFCO ops are very common, as timing events for long Neutral coasting is few and far between. I use recirc in traffic just to keep the exhaust gases at bay and retain dehumidied air inside.

After the tint install, I've been using the Drivers window down more as the heat load in the car is far lower. I can fix the FF at 1.00gph, and rolldown /rollup the window, and see no change in mpg running at 50mph, my favorite speed. 70% of my return trip in the afternoon are country roads with shade and scenery. I hit the Sirius Blues Channel, roll the window down and set the FF. I'm home before I'm ready to get there!

I had a best on my return trip home today, at ~75 OAT, and average IATs around 105, window down, 24.9 miles, average 47mph, at 49.5mpg. Summer gas and calming blues, I reckon.

__________________
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Video: Fuel Economy Decrease with Opened Windows Peakster Aerodynamics 21 04-30-2008 01:13 AM
It's not just the A/C tasdrouille General Efficiency Discussion 4 04-18-2008 12:57 AM
When does having your windows down start to effect your mileage? Chris D. Aerodynamics 9 03-11-2008 01:15 AM
Windows down on VW Golf = 2.5% FE reduction MetroMPG Aerodynamics 2 11-28-2007 09:43 AM
Found a coastdown hill! Mini comparo: windows vs skirts vs hatchback MetroMPG Aerodynamics 4 11-28-2007 12:40 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com