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Unread 07-05-2010, 09:41 PM   #16
ncb
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Unless you know exactly how many gallons it took to top off the tank after the trip your math is inaccurate.

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Unread 07-05-2010, 09:58 PM   #17
ak67sd
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you need to go through a few tanks to get a better average, and fill the tank and reset the trip odometer... you will have 100+ miles left with the fuel light on!

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Unread 07-05-2010, 10:29 PM   #18
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OP--no such thing as an 06 UL Sahara unless you're talking about the limited edition Sahara Rubicon.
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Unread 07-05-2010, 11:17 PM   #19
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Unread 07-06-2010, 12:13 AM   #20
planman
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Automatic JKs suck due to the 0.69, ubber-tall overdrive gear.

They come way undergeared stock.

To run the same rpms at 70 mph as a 6 speed, automatic Rubicons would need 4.88 gears with stock tires.

Because automatics are way undergeared stock, they downshift frequently in windy or hilly situations.

When the transmission downshifts, it "flashes the converter." This essentially runs the rpm levels higher than would otherwise be reached with the overdrive turned off, and it does this at almost wide open throttle.

So, in order to get the same gas mileage with an automatic as you did with your Sahara 6 speed, you would have to regear to a low enough gear to avoid downshifting, or slow down enough so the tranny does not downshift.

Wind resistance from speed, hills, cross-wind, and stock axle gearing with an automatic are not a conducive combination for good mpg.

FYI, my wife's automatic Rubi 4dr on 37s gets over 20 mpg at 65 mph with 5.38 gears and a Superchips Flashpaq programmer.

My 2dr Rubi 6 speed when on 37s got over 20 mpg at 65 mph with 5.13 gears and a Superchips Flashpaq programmer.
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Unread 07-06-2010, 02:15 AM   #21
Warlord2
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Quote:
My 2dr Rubi 6 speed when on 37s got over 20 mpg at 65 mph with 5.13 gears and a Superchips Flashpaq programmer.
Holy crap, thats 5mpg more then what I get with 35's and 5.13's doing an average 60-65 hand calculated with a gps. Did the Superchip Flashpaq make any difference? I didnt think a manual would even need one. I know I should coast at a lower rpm on the hwy once I get 37's but I never thought it would make THAT much of a difference...

ps: how is your mpg on the 40's?
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Unread 07-06-2010, 02:21 AM   #22
MilitaryJK4455
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I just got back from a trip to GA. I was running 60 at about 1900 RPMs in 5th gear with 3.73's and 35's and I was averaging 19mpg. Tested it on 2 tanks... Got 19 on one and about 18 on the other.
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Unread 07-06-2010, 07:52 AM   #23
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Quote:
Originally Posted by Warlord2 View Post
Holy crap, thats 5mpg more then what I get with 35's and 5.13's doing an average 60-65 hand calculated with a gps. Did the Superchip Flashpaq make any difference? I didnt think a manual would even need one. I know I should coast at a lower rpm on the hwy once I get 37's but I never thought it would make THAT much of a difference...

ps: how is your mpg on the 40's?
Not so great with the 40s. It dropped 2-3 mpg. I still get about 12-13 mpg in town, but at 65 mph it dropped to 16-18 mpg--depending on crosswind and hills.

JP Magazine rated tuner/programmers and determined the Flashpaq was good for a 7% increase in mpg. So that would be 1 mpg.

If you run your tires at about 32 psi on the highway, you might gain another 1-2 mpg.

I do have a Cherry Bomb glasspack exhaust. Maybe that is good for 0.5-1 mpg.

I gps verified distance and speed, and I hand calculated mpg. The in-dash computer is actually very close.
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Unread 07-06-2010, 08:46 AM   #24
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Originally Posted by Imped View Post
OP--no such thing as an 06 UL Sahara unless you're talking about the limited edition Sahara Rubicon.
Where did he say 06?
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Unread 07-06-2010, 08:53 AM   #25
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I get 21 mpg at 80 mph with my 2 door JK X.

It's lifted, is Flashpaq tuned, air dam removed, 3.73 gears, auto tranny, and 32'' tires.

Iv found it helps to find a SUV to drive behind. Not tailgate, but just enough to help with the wind resistance.
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Unread 07-06-2010, 09:30 AM   #26
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Quote:
Originally Posted by planman View Post
FYI, my wife's automatic Rubi 4dr on 37s gets over 20 mpg at 65 mph with 5.38 gears and a Superchips Flashpaq programmer.
You give me hope...........................
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Unread 07-06-2010, 01:31 PM   #27
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The in dash showed 14 mpg and on the way back not using cruise control I was able to get 15.3mpg. I did the math wrong initially but still should be getting better mileage with a stock Rubi.
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Unread 07-06-2010, 01:50 PM   #28
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Originally Posted by quag1509 View Post
The in dash showed 14 mpg and on the way back not using cruise control I was able to get 15.3mpg. I did the math wrong initially but still should be getting better mileage with a stock Rubi.
Easily. My Rubi Unlimited is an Auto, but the in dash MPG calculator showed 19.8 at the end of my trip.. and that included a fair amount of stop-and-go holiday traffic on the return!

My Rubicon is bone stock as well.
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Unread 07-06-2010, 01:58 PM   #29
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Sounds like something is wrong. I just did over a 3,000 mile trip with a '10 Rubicon Unlimited - Automatic and I averaged around 17 mpg for the whole trip. I was getting 16 up North going up and down all of the hills and 18 was I got down south where it was flat. The cruise was set on 74 to 78 depending on traffic flow. By the way South Carolina had the best gas prices - $2.39 a gallon.
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Unread 07-06-2010, 02:51 PM   #30
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Originally Posted by waterboarder View Post
That's about what I get - 12, 13MPH.

You don't drive very fast do you?
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