Gas Milage?

Just wondering? My 08 JK is completly stock except for my tires I have 285/70/17 BFG KM2's and my gas milage went from about 18-20 to like 12-16 does that seem right? Is there anything I can do that wont cost me an arm and a leg to improve it? Any suggestions would be appreciated.

You can always go back to stock tires, but that is really not an option. Do like the rest of us - dig a little deeper in the pocket when gassing up.

16 mpg seems about right for a 4 door. What size did your jeep come with? 255/75s or smaller?

Your overall tire size didn't really increase all that much. I'm guessing you started with a 255/70R18 on gladiator wheels since you have a Sahara. That means your stock tires were theoretically 32x10. Now your new tires are theoretically 33x11.25. That is a bit more rolling weight, but the change in tire size is only like 3%, so it shouldn't be that far off. The speedometer will be off and consequently so will your mileage. if you have the GPS, use it to compare 10 miles of driving against what your odometer says. Your odometer should be off by 3-5%.

About the only cheapest thing you can do to correct the problem is get yourself a Superchip Flashpaq or similar. They allow you to do all sorts of things, including recalibrate your speedometer for larger tire sizes. The Superchip runs around $340, but they might have a $25 rebate going on.

I know..... What an ass!.... I don't know of anybody that bought a jeep for fuel economy. Now with that said, they are, what they are POS!!!! when it comes to engine performance of ANY kind. When it comes to getting fuel economy back out of a rigged out jeep, there is nothing you can do. I've spent close to $1200 just to back to 16-17 mpg and even then that's not totally accurate. It's still around 14-15 real world. Is it worth it just to gain 2-3 mpg? HELL NO! does it make it tolerable? eh...yea. There is no easy "fix". The ones that say, "I'm getting 20 mpg on my jeep" are full of shit! There is no after market product that can get you that high in these pigs.

How many miles? Have you tried a tune-up?

On mine, we lost mileage around 42k, replaced plugs and got it back to 15-18. (that's with 35s and 5.13 gears)

and a super charger

Sounds about right...Guess I was just more curious than anything. I love my Jeep regardless.

Chris wrote:

and a super charger

that was put on later.

24K purchased jeep (35s & 3.73s) (nov. 09)
25K - k&n & superchips
36K - 5.13 gears
42K - spark plugs needed to be changed
51K - supercharger

jeep now has 67K and rolling. When I bought it it already had 35s, so I never got to experience the stock mileage on a jeep. I LOVE my flying brick, mileage could be better, but it's a give and take relationship.

A $1000 1995 Honda CRX commuter car would be the cheapest way to get good milage.

Jeeps have the aerodynamics of a brick and the oversize tires don't help.

Look at the bright side.....it could always be worse. 20 years ago I had a built up '77 CJ5 with a hot rodded 304 V8 that got 6 or 7 mpg on a good day. It did not help that it had a 19? gallon tank that was smashed and dent to a point it held maybe 12-13 gallons.

HerJK-X wrote:

I LOVE my flying brick, mileage could be better, but it's a give and take relationship.

Yeah...

...you give the gas station all your money...
...and your Jeep takes all the gas and converts it into carbon-dioxide, water vapor, and some other incidental items.

It's a win-win scenario.

I get about 12 on my 4dr
auto, 37"s, 5.13s and an assload of extra weight

FWIW, I'm running a 4" lift with 315/70R17's with a Superchip tow program. I get 16-18 with about 60/40 hwy/city driving.

Also, I just drove to the bay-side of Houston and back this past weekend. Going out I had an ESE wind and averaged a rather distasteful 16.1 MPG . coming back I got 19.5 MPG with a SW wind for about half the run. I was rather hoping to see above 20. Wishful thinking I guess.

I plan on running a 91 octane set in my Superchip with my next tank or two. I suspect I won't see much difference other than the amount of money I give to the gas company. I will then try a 93 octane set for a tank or two. The gasoline gods will be smiling then for sure!

Let me know how it goes HOOK. Alos I was wondering, with that superchip how is your horse power?

The horsepower gain is nice. Not a HUGE difference but nice.

Cool Thanks. Anyone selling one thats not vin locked for cheap?????

Call Phil at trail duty, fellow jeeper, he hooked me up with my flashpaq about a month ago for 290$ with no shipping. Best deal I've heard of. Also, the horse power gains are probably non-existant. What it changes is the throtle response. Instead of having to mash the gas to get going, just simply tapping it will get you moving. Also it will recalibrate your spedo and those two things in themselves are worth it. The other stuff is just nice.

Also, keep in mind that Hook-em is running A-T's where Lonestar Rubi is running M-T's, Toyo's at that. The A-T's are not only lighter, but they will offer less rolling resestance (The "hum" produced by most off road tires) than the M-T's and thus the added gas milage.

If you are looking for a fix, buy a honda. The above deal sounds good.

Im good no honda for me!!!! Thanks for the info, I will def. look into a super chip flash pack.

Check this thread out. https://myjeepforum.forumakers.com/t4597-selling-my-junk-p#62256. It might be the cheapest and fastest way to solve your problem. You're looking for the AEV Procal module.

JEEP

Just Empty Every Pocket !!!!!!!!!!!!