RedJK2

I'm trying to understand why a higher RPM is being correlated with lower mileage. Does that equate to greater fuel consumption? It was my understanding that more throttle means more gas into the engine. Therefore downshifting, when appropriate, should improve mileage.

Blakspire

I rock 35" Toyos, second set. Best damn M/T on the market.

jfbullseye

I have 35s with 4.88 gears, 6 speed man. and Im rockin around 20mpg . It allso depends on how you drive .

rexicon

Do people even read the op's thread

Stoneaxe

That's interesting. I run 35's and have 5:13 gears. Cruise set at 75 mph I get about 17 mpg, less if there's a head-wind.

I read a gas mileage post on here awhile back that seemed to make alot of sense. It spoke about throttle and the torque curve for the engine. Mean the engine produced the most power and ran the most efficiently at around 2400-2600 rpm. With 35's and 5:13's this is where the engine rides at about 70 mph.

I'm doing a poor job of explaining it.

nortski3

I'm running 33s and like them. I have the superchips and average 16 to 17mpg.
What is your purpose for the tires. Some guys go with 35s just for the looks and 33's would have gotten them down 90% of the trails they run anyways. The wrangler is plenty capable on 33's

Moab: both jeeps on 33's

http://www.youtube.com/watch?v=20DIFl8iuNw&sns=em

nthinuf

As was mentioned just above, this engine seems to be the most efficient in the mid-2k range. The OP has an auto, so you have to take into account that running too low of rpm on the freeway will cause a lot of shifting in and out of OD, which totally kills mpg's. It may seem a bit counter-intuitive, but running higher rpm's keeps auto's in OD longer, which actually improves the mpg. That said, the issue I see with the OPs setup is that he has stock gearing and tires, and is running with OD Off, so his rpm's are up near 3k. OD on should keep him at his stated 65mph driving speeds without much issue, and will raise the mpg's.

For those that go to taller tires, re-gearing to get the freeway rpm's into that mid-2k range is a good thing.

Anaya

I have 35" w/5:13 gears and a auto 2450 @70 MPH runs good and gets around 14 to 16 MPG depending on wind,road and how heavy your foot is.

D_engel

With 3.73s you may reach a point where your rpm's are turning too low at 65. The engine wont be operate in its max range of efficiency so you may lose some mpg

Love Monkey

I have 35's and 3.73 and am automatic. I just filled up right after the switch and then this morning.
Running stock I was about 18mpg. This tank on 35's I was 15mpg.

BUT I have not yet recalibrated my odometer for the tire size so the mpg is actually better AND I was driving with O/D on which means my RPM's were not running as efficiently. (I am learning!!) So, realistically, my mpg is BETTER than 15!

I do a combination of highway driving on the weekends and surface streets during the week.