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Gas mileage discussion... gas isn't expensive enough yet.
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=51&t=2197		 Page 1 of 1
Author:  Tightwadsjeeper [ Mon Sep 26, 2005 10:41 am ]
Post subject:  Gas mileage discussion... gas isn't expensive enough yet.
Ok.... went to visit a friend out of town this weekend (Tampa to Gainesville and back). Did all the usual stuff pre-trip (checking tire pressures, oil, etc.) and hit the road just before 9am.

The Interstate (I-75) was IMO a *little* less busy with traffic than it usually is on the weekend, but judging from the way everyone was driving they're sure not worried about the cost of the fuel they're burning. I put the cruise on 60 mph and since the weather was very nice I put all the windows down and opened the sunroof for the ride. During my two hour ride up there I passed 5 cars. Three of them were in a little convoy doing about 59 mph, and the other two were broken down on the side of the road. I lost count of all the large trucks and SUV's that passed me doing 70+ mph. On the ride back I passed 6 cars. Three of which were broken down... the other three were doing between 55 and 58 mph (obviously trying to conserve on gas like me). IMO obviously, for the people who can afford to travel the interstate at least, gas isn't expensive enough yet to make them change their driving habits. I got passed by at least 3 H2's on the way up that were all going well over 70 mph IMO.

Gas mileage details: 2005 Jeep Liberty 4x4 with 3.7L engine, stock Goodyear ST tires at 35 psi. All but about 40 miles of driving was highway mileage @ 60 mph with the windows down and AC turned off, with the balance being mostly stop and go in town driving, in Gainesville, with the AC on full blast.

318.3 miles total trip mileage on 13.244 gallons of gas = 24.033 mpg :)

Think people will start to change their driving habits when gas hits $4 per gallon? :roll:

Luis
Author:  auggy [ Mon Sep 26, 2005 10:44 am ]
Post subject: 
I guess it depends on your resources. Also, I doubt you saved THAT much more gas than the people who were doing 70 ( as long as they werent stopping and starting a lot with quick accelerations ) ...

I dunno though
Author:  Tightwadsjeeper [ Mon Sep 26, 2005 11:12 am ]
Post subject: 
I guess what I'm getting at is that although I hear most everybody whining about the high price of gas ($3 per gal or so) I don't see many people making any attempt to change their driving habits.... obviously it's not all THAT expensive yet.

Luis
Author:  Se7enLC [ Mon Sep 26, 2005 11:21 am ]
Post subject: 
auggy wrote:
I guess it depends on your resources. Also, I doubt you saved THAT much more gas than the people who were doing 70 ( as long as they werent stopping and starting a lot with quick accelerations ) ...

I dunno though


If the EVIC is accurate, there's a huge difference. I found that when I sit in 6th gear and behave at 65mph, I get 23mpg, pretty regularly. When I speed up to 70 or 75 to keep up with traffic, it drops down to 19mpg or lower.

I'm toying with tire pressure now, too - I just brought my tires up to around 40psi, and it seems to already be affecting my gas mileage pretty positively. I'll know for sure when I fill up and check the tripmeter, but the evic had an average of over 20 even in town.
Author:  kj lad [ Mon Sep 26, 2005 11:37 am ]
Post subject: 
I don't see people changing their cars either! In the UK you don't see many V8's (or V6's for that matter) because of the price of fuel. But I wouldn't wish our fuel prices on you that's for sure.

Ian
Author:  VTNomad [ Mon Sep 26, 2005 12:07 pm ]
Post subject:  Windows vs. AC
Driving with the windows down at 60 mph probably hurt your mileage more than A/C would have. But just driving around town the windows would be the better option.
Author:  Eddo [ Mon Sep 26, 2005 12:49 pm ]
Post subject: 
Gas is more than expensive enough for me. Maybe if I made 6 figures I wouldn't mind that much.

Essentially the larger income you have the less affect gas prices have on you. Hence, why the guy driving the H2 doesn't care that he is getting 12mpg at almost $3/gallon. He also can affored a 50k+ SUV what is a couple extra hundred bucks a month.
Author:  GregB [ Mon Sep 26, 2005 12:59 pm ]
Post subject: 
I drive my car instead of my KJ 35 miles to work. I've found that by going 60mph on the a highway I get 31-32mpg. When I take the interstate at 70 mph I only get 29mpg. :x Best I've been able to get out of the 02' KJ is 21mpg, but usually get much less, like 15-17 in town. For some reason 02' EPA ratings on mpg are less then newer KJ's.
Author:  Tightwadsjeeper [ Mon Sep 26, 2005 1:45 pm ]
Post subject:  Re: Windows vs. AC
VTNomad wrote:
Driving with the windows down at 60 mph probably hurt your mileage more than A/C would have. But just driving around town the windows would be the better option.


That's a myth. At "LOW highway speeds" (perform a search for topics where this has been discussed at length... there are actually independant tests that have been run to disprove this)... you'll actually get better mileage with the windows down and AC off ... obviously, it may not apply when you start talking about speeds of 80+ mph where the wind effect is MUCH greater.... but at the speed I was going, it should have been slightly better (keep in mind that we're only talking about a difference of something like .25 mpg).

Believe me.... had the temp been in the usual mid 90's we see here, I'd have been running the AC regardless of any difference in mileage.

Luis
Author:  Guyute1210 [ Mon Sep 26, 2005 4:05 pm ]
Post subject:  Re: Windows vs. AC
Tightwadsjeeper wrote:
VTNomad wrote:
Driving with the windows down at 60 mph probably hurt your mileage more than A/C would have. But just driving around town the windows would be the better option.


That's a myth. At "LOW highway speeds" (perform a search for topics where this has been discussed at length... there are actually independant tests that have been run to disprove this)... you'll actually get better mileage with the windows down and AC off ... obviously, it may not apply when you start talking about speeds of 80+ mph where the wind effect is MUCH greater.... but at the speed I was going, it should have been slightly better (keep in mind that we're only talking about a difference of something like .25 mpg).

Believe me.... had the temp been in the usual mid 90's we see here, I'd have been running the AC regardless of any difference in mileage.

Luis

I believe you are wrong, Myth Busters TV show did an episode on this one, and through town, windows down/ AC off is best for driving in town, and at Highway speeds (>55MPH) AC on and windows up were best b/c of wind resistance with the open windows.
Author:  Tightwadsjeeper [ Mon Sep 26, 2005 4:54 pm ]
Post subject:  Re: Windows vs. AC
Guyute1210 wrote:
Tightwadsjeeper wrote:
VTNomad wrote:
Driving with the windows down at 60 mph probably hurt your mileage more than A/C would have. But just driving around town the windows would be the better option.


That's a myth. At "LOW highway speeds" (perform a search for topics where this has been discussed at length... there are actually independant tests that have been run to disprove this)... you'll actually get better mileage with the windows down and AC off ... obviously, it may not apply when you start talking about speeds of 80+ mph where the wind effect is MUCH greater.... but at the speed I was going, it should have been slightly better (keep in mind that we're only talking about a difference of something like .25 mpg).

Believe me.... had the temp been in the usual mid 90's we see here, I'd have been running the AC regardless of any difference in mileage.

Luis


I believe you are wrong, Myth Busters TV show did an episode on this one, and through town, windows down/ AC off is best for driving in town, and at Highway speeds (>55MPH) AC on and windows up were best b/c of wind resistance with the open windows.


Here's Data from SAE showing otherwise. http://www.sae.org/events/aars/presenta ... 4-hill.pdf
please note the figures are in GPH (Gallons Per Hour) not MPG (Miles Per Gallon)

Here's another article summarizing some of the SAE data.
http://www.treehugger.com/files/2005/06 ... or_d_1.php

And here's an actual test yielding the same results.
http://www.edmunds.com/ownership/drivin ... sonly..4.*

Like I said... the difference at highway speeds IS small enough that there's no reason not to use the AC... but there IS still a small advantage to going with the windows down.... provided it's not an unpleasant experience... you won't see the AC take an advantage until the difference in air drag becomes sufficient to surpass the HP loss to the compressor.

Luis
Author:  Guyute1210 [ Mon Sep 26, 2005 5:13 pm ]
Post subject:  Re: Windows vs. AC
Tightwadsjeeper wrote:
Here's Data from SAE showing otherwise. http://www.sae.org/events/aars/presenta ... 4-hill.pdf
please note the figures are in GPH (Gallons Per Hour) not MPG (Miles Per Gallon)

Here's another article summarizing some of the SAE data.
http://www.treehugger.com/files/2005/06 ... or_d_1.php

And here's an actual test yielding the same results.
http://www.edmunds.com/ownership/drivin ... sonly..4.*

Like I said... the difference at highway speeds IS small enough that there's no reason not to use the AC... but there IS still a small advantage to going with the windows down.... provided it's not an unpleasant experience... you won't see the AC take an advantage until the difference in air drag becomes sufficient to surpass the HP loss to the compressor.

Luis


I stand corrected...thanks Luis!
Author:  Tightwadsjeeper [ Tue Sep 27, 2005 10:48 am ]
Post subject:  Re: Windows vs. AC
Guyute1210 wrote:
I stand corrected...thanks Luis!


You're welcome! Only found that out myself a month ago or so.....

Luis
Author:  kj lad [ Tue Sep 27, 2005 5:20 pm ]
Post subject: 
The windows v AC is a different thread :?:

Ian
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