Gas Mileage...don't laugh

[MacGuyver]

The 3.8 gets worse mileage than the 3.6.

15 MPG isn't unheard of for the 3.8, especially considering their age at this point.

33" for a 3.8 sahara is pretty much max given that you probably have 3.21 or 3.73 gearing. There is a gearing to power / tires size ratio chart for the 3.8 somewhere on these forums. Pops up in a thread ever other week or so.

 

[Jino]

View attachment 119667

I took my hood bumpers off recently. Got some 1/2" Hillman plugs at Lowe's, popped 'em in.
I'll bet that improved my gas mileage by about .0003 mpg.

Maybe adding these will help

 

[BLACKJKU]

The 3.8 gets worse mileage than the 3.6.

15 MPG isn't unheard of for the 3.8, especially considering their age at this point.

33" for a 3.8 sahara is pretty much max given that you probably have 3.21 or 3.73 gearing. There is a gearing to power / tires size ratio chart for the 3.8 somewhere on these forums. Pops up in a thread ever other week or so.

It's in the How to section near the top.

 

[AUBoggs]

Getting 17.3 with 2.5" lift and 35s on a 2018. I did measure the tires for height and reset the computer. I run the tires at 24psi. Gears are still stock, 3.21.

 

[Jermbob28]

Regear now runs about 2k to 2.4K in CA where I live.

 

[SteveF]

So, how was the calibration done? If you simply entered a 33" tire diameter into JScan or a ProCal, it's not accurate. You should really measure the height of each wheel/tire from the ground to the top of the tire, figure the average and use that. Just plugging in 33, when it's really closer to 32 is going to throw it off.

Do you know if the JKU was re-geared at any time? When you get to cruising speed on the highway are you easily running in 6th gear or are you having to downshift at the slightest incline?

I have a 2015 JKU automatic with 35's. At highway speeds it would downshift from 5th gear at the slightest incline. I had 3.21 gears. Now with 4.56 gears there is no downshifting.