Improving loss of mpg's

MedixJK

MedixJK

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So being new to this jeep thing, im gonna throw this out there because my jku is my DD. 2012 jkus w 3.21. I went from my jeep saying i was getting 18ish mpg avg, to now 12-13 mpg avg. I did a 2.5" coil lift and put 295/70r17 mxts on factory wheels with spacers. I havent recalibrated anything yet but looking at a superchips unit to get back a lil mileage. Will that help? Any other ideas? Im currently tracking the milage manually but havent refueled yet.
 
cozdude

cozdude

Guy with a Red 2-Door
mattbeach said:
So being new to this jeep thing, im gonna throw this out there because my jku is my DD. 2012 jkus w 3.21. I went from my jeep saying i was getting 18ish mpg avg, to now 12-13 mpg avg. I did a 2.5" coil lift and put 295/70r17 mxts on factory wheels with spacers. I havent recalibrated anything yet but looking at a superchips unit to get back a lil mileage. Will that help? Any other ideas? Im currently tracking the milage manually but havent refueled yet.
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yes it will. if you havent recalibrated then the computer isnt going to reconize the new tire size so the average mpg that shows isnt going to be right. also your shift points will be off so that will contribute to the mpg lose as well. i would look at the superchips flashcal or aev procal to correct everything with the computer
 
wayoflife

wayoflife

Administrator
Staff member
As mentioned, you NEED to properly calibrate your speedometer. It will not only give you a more accurate reading, it will also restore your shift points.
 
MedixJK

MedixJK

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wayoflife said:
As mentioned, you NEED to properly calibrate your speedometer. It will not only give you a more accurate reading, it will also restore your shift points.
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Thanks for pointing me in the right direction. You guys have all been great help. I can tell that it wants to shift at all the wrong times, or not shift at all. Definately gonna check those units out.
 
wayoflife

wayoflife

Administrator
Staff member
AEV ProCal or Superchips Flashcal will get the job done and for cheap. You just need to make sure you measure your tires correctly and not just go off of what is stated on the sidewall. Specifically, you need to measure from the ground up to the corner where your sidewall becomes the tread or, measure from the center of your wheel to the ground and x2.
 
sierra141

sierra141

New member
I would go with AEV, I have the exact specs as yours, but I did my research before buying a tuner and ended up with AEV, the reviews are better than superchips.
 
cozdude

cozdude

Guy with a Red 2-Door
sierra141 said:
I would go with AEV, I have the exact specs as yours, but I did my research before buying a tuner and ended up with AEV, the reviews are better than superchips.
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The upside to the superchips flashcal over the AEV is the fact you have a screen to see exactly what you are doing and read codes. The other benefit to it is that you can upgrade it to a flashpaq for an extra $150 later down the line instead of buying a whole new unit
 
terrabit

terrabit

New member
wayoflife said:
As mentioned, you NEED to properly calibrate your speedometer. It will not only give you a more accurate reading, it will also restore your shift points.
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I don't believe calibrating the speedo for larger tires will do anything like restoring shift points. At least not for 2012+. It didn't do anything for mine.
 
TheDuff

TheDuff

New member
terrabit said:
I don't believe calibrating the speedo for larger tires will do anything like restoring shift points. At least not for 2012+. It didn't do anything for mine.
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Shift points are rpm AND speed based. So how could properly correcting your speedo for larger tires not restore shift points? Where you expecting some sort of power gain?
 
Rebel JK

Rebel JK

New member
I like my traildash a lot. Its really nice to be able to get the additional readings like tranny temp, plus a lot more including back up camera input. The only drawback for me is it takes a few minutes to reprogram between power modes.
 
terrabit

terrabit

New member
TheDuff said:
Shift points are rpm AND speed based. So how could properly correcting your speedo for larger tires not restore shift points? Where you expecting some sort of power gain?
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No, I was not. The physics involved do not permit a power gain by way of recalculating tire size. In this case the tire is effectively a lever. Increasing tire size is effective moving the fulcrum in relation to the lever such as to decrease mechanical advantage.

And actually, rpm and throttle position are the primary drivers of shift points. Speed has very little, if anything, to do with it. Sometimes it's better to just listen rather than insulting someone because you disagree.

Also, the NAG1 transmission runs off of a separate ECU. It is not accessible from the OBDI-II port - nor has it been successfully hacked by any of the usual suspects.

By all means, correct me if I'm wrong. But please back it up with facts.
 
MTG

MTG

Caught the Bug
terrabit said:
It's not rocket science.
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Whoa tough guy! Sometimes it does not take is all. But it seems like you have all the answers so I'm sure your good. Nobody is questioning your internet manhood. BTW--give Prime8 my regards. ;)
 
TheDuff

TheDuff

New member
terrabit said:
No, I was not. The physics involved do not permit a power gain by way of recalculating tire size. In this case the tire is effectively a lever. Increasing tire size is effective moving the fulcrum in relation to the lever such as to decrease mechanical advantage.

And actually, rpm and throttle position are the primary drivers of shift points. Speed has very little, if anything, to do with it. Sometimes it's better to just listen rather than insulting someone because you disagree.

Also, the NAG1 transmission runs off of a separate ECU. It is not accessible from the OBDI-II port - nor has it been successfully hacked by any of the usual suspects.

By all means, correct me if I'm wrong. But please back it up with facts.
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Didn't know you where a engineer, my bad. I wasn't out to insult you, sorry you took it that way. But in regards to my input about speed, it's been my experience that there are set minimum speed requirements for obtaining full torque converter lock up. Maybe you are right, it's just throttle position and rpm, maybe it's different for 2012+? I have an 2009 and prior to calibrating my speedo I had issues maintain torque converter lock up on steeper grades. Needless to say, after calibration maintaining the proper gear and TC lock up was a non issue and my Trans temp is much happier. Sorry if I came off as insulting.
 
terrabit

terrabit

New member
TheDuff said:
Didn't know you where a engineer, my bad. I wasn't out to insult you, sorry you took it that way. But in regards to my input about speed, it's been my experience that there are set minimum speed requirements for obtaining full torque converter lock up. Maybe you are right, it's just throttle position and rpm, maybe it's different for 2012+? I have an 2009 and prior to calibrating my speedo I had issues maintain torque converter lock up on steeper grades. Needless to say, after calibration maintaining the proper gear and TC lock up was a non issue and my Trans temp is much happier. Sorry if I came off as insulting.
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I'm not an engineer but I have studied physics in both the academic environment as well as on my own, more so as it relates to helicopters and other flying things. Also rebuilt my first engine at roughly age 10 and have rebuilt many others since then. This doesn't make me an authority on anything but I know what I know. For instance, I know that TC lockup can only occur once the disparity between crankshaft and driveshaft, through whatever system of gears and hydraulic clutches, is effectively reduced to zero. A TC is essentially just a clutch that facilitates this process. They aren't what I'd describe as adjustable.

I can be a dick sometimes ... sometimes without even trying. I apologize, I might have been trying. I might also be a bit jaded. I'll work on that. I don't know Prime8 but my guess is this person might on occasion be just as arrogant, opinionated and condescending as me. I pity da foo!

Gearing is probably the most effective way to regain lost mpg. Minimizing weight and drag would be other areas of opportunity.
 
terrabit

terrabit

New member
MTG said:
Whoa tough guy! Sometimes it does not take is all. But it seems like you have all the answers so I'm sure your good. Nobody is questioning your internet manhood. BTW--give Prime8 my regards. ;)
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It's interesting that you would use the terms "tough guy" and "manhood" to deride me. But that speaks more about you than anyone else.
 
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