I have a 08 2D Sahara with 3.73's stock 18" wheels/tires and my wife has a 07 Unlimited X with 4.10 gears, factory 17" wheels/tires. Both are Autos, but hers gets about 2mpg's better than mine under the same conditions. I drove mine for a week and then hers for a week - my sahara gets about 16.5 and hers almost 19. These are around town conditions. I really thought that the 3.73 gears would get better mileage - especially being the lighter weight 2D and 1/2 inch taller tires. Mine has 900 miles - hers over 10K.

Any thoughts???

 

Yours certainly doesn't have many miles on it. Mine woke up and started getting a tad better mileage around 2200 miles. Why, I have no clue. I have seen others say the same thing.

 

Try it gain when you get a few thousand miles on your Jeep.

Are you hand calculating or going by the computer?

 

I was surprised that my 08 2dr. stock auto rubicon with 1000 miles got 23 mpg on a trip today from Charlotte NC to Columbus Ga (About 350 miles). This was with cruise set at 65. First vehicle I have owned that got better than the estimates stated on the window sticker. I get abut 17.5 to 18 around town. Does this mean it will be better with a few thousand miles and Mobil 1 (which I switch)?

 

I don't get it either. I have an 08 Sahara unlimited auto w/ 3.73 gears, and about 3000 miles on her. I'm only getting about 14 - 15 mpg around town and i live in the flattest city in ontario. Is there something wrong???? Might the jeep be calibrated for a different setup??? I want to put a BB and 35's on this summer but i'm afraid to get less then 10 mpg. BTW, I'm not flooring it from stop light to stop light. Very conservative driving. Any insight is greatful.

 

If you can stick to 65mph (hah!), you'll probably get even better MPG without cruise control. I've found w/most CC systems, they gas it too much going up hills and don't let off soon enough going down.

 

You got that right. Cruise controls are way more aggressive than the way I drive, too. My wife's Escape will actually stomp on it goin up a hill. Damndest thing I ever saw.

 

WOW your wifes JK is getting some good MPG IMO. My wifes 07 JK unlimited, auto with the 4.10's, stock 245/75/16 and stock alloys, broken in with 10K averages about 13.6 around town. Of coarse she only drives about 8 miles to work, and lets it warm up for about 10 minutes before driving, so she is most likely wasting alot of gas. We get around 19-21 on highway trips of about 4 hours driving one way.
Since you have the 3.73's you're probably into the pedal more to get the thing moving.

 

we park in a climate controlled garage so we don't have to let them warm up - my wife is a stay at home mom, so her trips are mostly very short as well averaging 5-10 miles. the only reason she hs put 10000 miles on it over the past 10 months is due to taking it to Fl twice and SC once. I cannot remember the milage it got then.

one thing your post made me think about...I wonder if with the 4.10 gears, the unlimited is hitting overdrive (or at least getting into one higher gear than the sahara) around town? if so, the sahara would be turning higher rpms than the unlimited...as well as what you said about taking more to get it going....

on that note, does anyone have a set of 4.10s they want to unload? dana 44 rear with traclok (if that matters)...I gues I should post that in the wanted section...

 

Swap wheels and tires with your wife, then get it recalibrated for the new setup. It will increase both of them.

Your jeep is not yet broken in so mileage and perfomance will improve.