I just had 5.13's put on my jk auto...35" nitto trail graps on 20" xd monsters.. it seems like my shift points are off and effecting the efficiency of the engine. I thought it would improve my not's but according to my dash I was getting 11mpg and worse at speeds of 65 to 70mph..
Now I'm happy with the power and the way it drives just want to know what could be done to fix this...

 

You need a programmer to fix your dash, it is still thinking it pushing 32's with stock gears. I would recommend doing hand calc's on your MPG until then.

 

Is that all that I can do? Anyone with same situation?

 

I have a AEV procal. I had an auto with 5.13s and nitto mud grappler 35x12.50r18s on 18x9 alum wheels. Even after shift points were corrected I never got over 14mpg and usually averaged 12mpg. Those tires are super heavy, and the lower pressure you have to run in them to make the high load range of them ride decent makes the situation worse too. I loved the mud grapplers offroad and the way they looked but that was my first and last set. They were just too heavy, rough riding, and gas guzzling for me.

btw the procal is only like $120 or so.

 

A Superchips Flashpaq will solve all of your problems. I also have 5:13s w/ 35s and the Flashpaq has my shift points dialed in.

 

Anyone?

EVERYONE with bigger tires and lower gears has the same issue. Live with it, or reprogram. The dealer can adjust the computer, up to 33's I think, at the big dealer upcharge. But you will be better off buying your own programmer, that you can use as often as you want, that has a lot of other great features...

 

Same here. Have the Superchip and all better....actually better than stock !

 

Sorry for that dumb comment I made... but I was just wondering if n e 1 had the shift point issue and when I fix it with flashpaq if it will help my mpg and overall functionality.

 

Your computer still thinks you are on small tires with stock gears - and has set the shift points accordingly.

Using a procal/flashpaq/whatever, you are re-programming your computer, telling it that you now have 35" tires and 5.13 gears, and your shift points/mpg readout/functionality/etc will now be improved because they are based on the correct information.


-you're riding your mountain bike up a steep hill. You can't figure out why it is so hard to pedal, since you 'know' you're in first gear. You mention it to the jogger running alongside you, he looks down and see's you are in 15th gear, not first. He tells you, you slap your forehead, and you re-program your brain with the new information. Shift down to first, and going up the hill is a breeze. Keep it in 15th, and you kill your legs trying to pedal...