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Unread 06-27-2013, 02:19 PM   #1
georgecj6
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Better MPG ....................

2008 Commander with 3.8V6 gets only 15 mpg.

What can be done to improve the MPG?

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Unread 06-27-2013, 02:52 PM   #2
Zlartibartfast
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keep those tires inflated!
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Unread 06-27-2013, 02:59 PM   #3
JRLT
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Reset your mileage counter.
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Unread 06-27-2013, 03:44 PM   #4
bhawks28
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you can trying using the search button to realize this topic has been beaten to a bloody pulp
http://www.jeepforum.com/forum/f67/p...liter-1054810/
http://www.jeepforum.com/forum/f67/g...ileage-415729/
http://www.jeepforum.com/forum/f67/h...e-mpg-1331011/
http://www.jeepforum.com/forum/f67/f...3-7-a-1214100/
http://www.jeepforum.com/forum/f67/g...again-1342606/
http://www.jeepforum.com/forum/f67/b...ileage-921020/
http://www.jeepforum.com/forum/f67/p...leage-1513668/

There's plenty more where that came from: https://www.google.com/search?q=site...ve%20mpg%203.7
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Unread 06-27-2013, 04:00 PM   #5
modernblueWK
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Drive downhill in a lighter vehicle?
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Unread 06-27-2013, 06:34 PM   #6
OhFiveHemi
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Trade it in for a Compass!!!

But seriously, yeah just click on of those links
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Unread 06-27-2013, 07:19 PM   #7
JackB1
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You can try anything but properly inflated tires,clean air filter, a light foot on the throttle and keeping highway speeds around 55 are the only things that work although I would be interested to see if non ethanol gas would improve mileage.
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Unread 06-27-2013, 07:39 PM   #8
JRLT
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Ya, Ive been using nothing but non ethanol gas for over a year and Ive seen better gas mileage.
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Unread 06-27-2013, 07:57 PM   #9
Zlartibartfast
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BLETHanol what a joke, but where do you get gas without it? All of our pumps are 10%

(glad my jeep runs on oil.....)

but yeah my brother tells me that 10% corn squeezin' cuts his WJ's 4.7 MPG's noticeably. He said it helps to run the 89 octane instead of 87

addendum - I just looked up specs on xkjeeps - you're actually close to getting the average EPA rated MPG:

ENGINE: 3.7-LITER SOHC POWER TECH® V-6
Availability ....Standard with 4x2 and 4x4 Commander



Power (estimated SAE net) ...210 hp (157 kW) @ 5200 rpm (58.1 hp/L)
Torque (estimated SAE net) ............235 lb.-ft. (319 N•m) @ 4000 rpm

Estimated EPA Fuel Economy
mpg (City/Hwy) .................................................. ..................16/19
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Unread 06-27-2013, 08:01 PM   #10
JeepN4KC
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Quote:
Originally Posted by georgecj6 View Post
2008 Commander with 3.8V6 gets only 15 mpg.

What can be done to improve the MPG?
Weird - I heard the 3.8s get awesome fuel econ




^^^ This - thnx.
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Unread 06-27-2013, 08:16 PM   #11
WieSeL
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Quote:
Originally Posted by georgecj6 View Post
2008 Commander with 3.8V6 gets only 15 mpg.

What can be done to improve the MPG?
3.8? Did you do a engine swap?
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Unread 06-28-2013, 09:31 AM   #12
jaje
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A gallon of e85 blend has ~ 25% less energy density than a gallon of gasoline. The converse is true where a gallon of gasoline has 25% less energy density than diesel. Only put in gasoline if you can as that will give you better mpg than any ethanol blend. People only run ethanol where they need it for detonation problems.
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Unread 06-28-2013, 10:23 AM   #13
JRLT
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Quote:
Originally Posted by Zlartibartfast View Post

but yeah my brother tells me that 10% corn squeezin' cuts his WJ's 4.7 MPG's noticeably. He said it helps to run the 89 octane instead of 87
In South Dakota, Ethanol is the 89 octane and Regular Unleaded is 87 octane.
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Unread 06-28-2013, 10:40 AM   #14
Jeepforthewin
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Unread 06-28-2013, 11:23 AM   #15
Zlartibartfast
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Quote:
Originally Posted by JRLT View Post
In South Dakota, Ethanol is the 89 octane and Regular Unleaded is 87 octane.
Really? they downgrade the midgrade blend? I wonder how much octane rating is lost by blending corn juice...

well anyway I think everyone agrees that better fuel = better efficiency, everything else being equal, for any vehicle

addendum - it appears that adding ethanol can actually raise the octane rating....

http://www.fuel-testers.com/gasoline...hanol_E10.html

http://pubs.acs.org/doi/abs/10.1021/ef101125c

so now I'm confused as to why folks report a decrease in MPG's w/E10
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