bbolander

I've had a 2" lift on my 2012 since new and typically got 18-19 mpg on the highway. Recently added bumpers, tire carrier, winch and went from 32" to 34" tires and lost some performance and 2-3 mpg. I corrected my tire size with my Superchips Trail Dash 2.

Last week I set my programming back to stock to take it in for service. After service, I forgot how to change the tire size back, and programmed in the 87 octane tune and then tire size.

My performance is much crisper, strong as ever with the 87 octane tune. And I've picked up a couple of mpg's as well. The tuner helps.

Jay Mike

Hello everyone, after three years of running ALL STOCK, finally having 3" lift with 35" BFG KM2 installed as I write. My question, is adusting your fuel and speedometer a DIY task? Or should I have a professional do this. Currently running 3.73's and planning to upgrade to 4.50's in a few weeks. Should I wait till then? Thank you all ahead of time.

resharp001

Ditto. Geared, tuner, loaded down with weight.....all amounts to poor fuel economy. It's ok, it's offset by the fun memories off the pavement.

resharp001

Adjusting tire size is all you need to do to calibrate your speedo, and it's easily accomplished with the various tuners out there. You will have to have a tuner for when you regear to adjust the computer for the new gears, so may as well play around with it a bit prior to having to program your gears. Get familiar with the interface of your chosen tuner. So yes, it's all DIY. Most of the tuners are very straightforward. The Superchips is a really nice interface. I can't recommend the Bully Dog that I use.

bbolander

You can do it yourself with a programmer. The least expensive Superchips Flashcal and AEV ProCal will do tire size and gear changes. If you want to do engine tuning to get better performance you need the more expensive Superchips Flashpaq or Trail Dash 2 units. There are threads on programmers and tuners. You can do the tire size first, and the gear change later.

jedg

Yep, you need an AEV Procal or a SuperChips FlashCal.

Smudgeontheglass

I installed a 2.5" lift (lifted the front a lot more than that due to sagged springs) and it didn't really affect my fuel economy. Once I put on a set of 35" Trail Grapplers without regearing from 4:10, my economy tanked. I went from 10-13L/100km on the highway to 16-19L/100km. With a light bar installed I get better fuel economy during normal city driving at 60-80km/h.

The biggest detriment to fuel economy is wider tires. Lifting up does reduce your underbody aerodynamics a bit, but tire width not only wrecks your aerodynamic profile, but it also increases your rolling resistance and unsprung weight.

agentjohnson

I will disagree. I ran 33's after swapping the factory 32's for a whole year. shift points sucked, highway mileage was terrible, etc. I just tuned a few weeks ago, adjusted for tire size, and my shift points are much better, throttle response is perfect and mileage is 16 in the city 20 on the highway.

Monte417

Same jeep same mileage for me exactly

Valkyrie0002

My 09 was getting 20 - 22 mpg hwy until the 1.5" lift, bumper, sliders and skids. Same 32" tires and same flashed 87 tune. All those beefy steel parts added about 400lbs of weight. Now I'm lucky if I hit 20mpg hwy even briefly.