Running 35s auto and just installed the 513s, while the drivabilty is vastly improved, the mpgs are about the same around town 13ish, I thought I would see improvents here. I have NOT recalced the speedo yet

 

We're getting 16-17 with our 6 speed. I know its not what you asked... but it seems like it keeps improving with the mileage increasing.

When we installed the lift with 3,000 on the JK, we we're getting about 13.

 

Im stock right now and getting 20.4 drops in city but nothing less then 20 i think the one time i beat it i saw 19.9 i seem to get really good mpg with it what is everyone getting with there jk?

 

My stock X 6-speed is getting around 20 (generally 19.5 to 20.8) unless I'm hauling a trailer full of firewood; most of my driving is highway (285) down into and back up out of Denver and then some local driving around Bailey.

 

I don't think you're going to get anything remotely accurate out of the computer until you tell it what you have.

Or are you calculating by hand?

 

The previous poster is right that without recalibrated the speedometer you numbers (all of them) will be way off. But, with that said, from all I have seen 4.88's are the way to go to bring mileage closer to stock with 35's. While the 5.13 users seem to love them for the improved drivability, the general consensus seems to be that they are a little tall for 35's and might not buy you back quite as much mileage as the 4.88's would have.

 

Running 37's with 5.13 gears. I get 15.5 from the 2dr, and it has been really hot here. (makes mileage worse)
If the speedo is wrong and not calibrated for the change it will be VERY complicated to calculate mileage, even by hand.
Unless you use some external device to track real mileage and then gallons used.
I recalibrated mine with the Hypertech programmer, and verifed its accuracy for speed/ distance.

Enjoy the quick response from the tall gears, and you will not get as good of mileage if you drive a lot of highway speed travel, but it wont effect much if you mostly wheel and drive "in town".

Best wishes.

 

Well I noticed about a .5 -1 mPG increase with the 5.13's. But I am not careful at all and dont do much freeway driving. With an auto I would not go less than the 5.13s.

 

I get 19-20 at 60mpg on the hwy with auto and 5.13s. I have to stay under 65 or the mpg drops quickly.

For all around driving, I get 16-17 or so.

 

With 5.13's, 33" tires, auto, getting 15mpg around town, 16-17 on highway. GPS'ed the speedo which is exactly on and divide miles by gallons each time. And....Hypertech with CAI and Magnaflow muffler. Need all this to pull small trailer. About 2mpg less with trailer. Also,
computer always about 1 mpg more than real.