scouter4life

X2, running 285's with tons of extra weight (see signature) and I just refilled and was at 19 mpg's. This is a daily driver with mix of stop and go and freeway. During the summer I'll usually get over 20 mpg's. It's all about the skinny pedal, these are not speed machines, no reason to shoot off the line.

wolfmanii

I can not believe it. I did some long trip on I75, cruising at 70mph, at the MPG
can barely reach 15mpg. Your JK must be a miracle!

Flip94ta

I've done a lot of long trips on I-75 too. No matter what vehicle I can set the cruise at 70 and get the newer (2008) EPA highway number. Now a head wind or driving faster than 70 will sink it. I drove with my younger brother recently. I'd call him compeletly typical. GAS-BRAKE-GAS. What about coasting?? I'm doing less than 60 every my vehicle enters the off ramp, yet the person behind me still has their cruise on 75 yet we will both be stopping at that big red light ahead. If you can ever spend some time in a car that gives instant mpgs like many GM or BMW's it will make you a lot thriftier on the gas pedal.

tpm152

A JK getting 20 mpg isn't a huge deal. I have the stock 32 inch tires with 3.21 gear ratio and the 6-speed and periodically get hand calculated 22+ mpg on the highway (even on winter gas). I have an unlimited so my gas tank is about 21.5 gallons but if I do mostly highway driving I usually get over 400 miles per tank, even on winter gas.

Flip94ta

Hey tpm,

I'm thinking of ordering my JKU with 3.21's and the six speed. How often do you have to shift out of 6th on the highway? I usually cruise at 70 and I'm hoping it would hold the top gear. I'm waiting on the pentastar but I'm thinking they will be close in power at 2000 rpms.

scouter4life

Cruising at 70MPG's? That's your problem, try it at 60 and your MPG's will be way better. It's been discussed at great length and over 60 the JK's lack of aerodynamics kicks in exponentially. I too have experienced that, On my daily commute I don't exceed 60 and drive the speed limit on all streets. Slow acceleration, not topping 60 (unless speed limit is 70+) and doing the speed limit you will get great mpg's.

As for what I get, I just filled up earlier today. I reset the mileage at every fill up and calculate the mpg's. The fill up earlier today was right at 16 gallons and I had done 310 miles, math works out to 19.375 miles per gallon. That's with doors and windows on and winter blend gas. Doors off and windows off with summer blend I get 1-2 mpg's better.

tpm152

It holds speed great on the highway. In local highway commuting I never have to downshift from 6th at all and in fact I typically have it in 6th gear at any speed over 35 mph to help save gas around town as well (keeping the RPMs at ~1100 - 1200 and giving an average of 17 mpg in town). The only time I can think of a time when I had to downshift to maintain speed was this past summer when my family went to my brothers graduation from Ohio State in Columbus. I started driving from State College, PA with a full tank of gas and drove to Pittsburgh where I picked up my parents, their dog, and their luggage. From Pittsburgh to Columbus we had 4 people, a golden retriever, all our luggage, and a huge cooler full of ice, beer, and food (through some steep mountain highway passes in northern WV). It was an 85 degree day so we had the air conditioning going full-blast the entire time. I only had to downshift to 5th gear two or three times to maintain 75 mph up the steepest mountain highway passes in WV. The other beauty of it was I did not fill up with gas until after some local driving around Columbus with over 400 miles on the clock. I can remember that I got 21.5 mpg hand calculated average on that trip (not bad for fully loaded with the AC running full-blast!)

I will say it will depend more on you than the JK in a way whether you like 3.21 gears. Many people on this forum want JKs get get up and go fast. For them they need the higher gear ratio to get better acceleration. I personally bought my JK to get good fuel economy at the same time as driving slow with the top down, music up, and the option of going 1 mph off-road (where once 4-low is engaged you are good to go as far as you would ever want to take a stock JKU) which is why the 3.21s work for me.

coorsfan

Keep in mind that if you go with 3.21 you will notice it when you go to wheel off road. That's why the Rubi come stock with 4.10 and some models have a 4.10 option.

Flip94ta

Thanks for the good info. Are you running 30 or 32 inch tires? I would love some 3.55's like my XJ had. I'm only getting 18 mpg's babying my Rainier right now so I am hoping on getting 21ish out of the pentastar.

tpm152

I have the stock 32 inch tires (255/75R17 size to be exact).