Improving the JK fuel efficiency?

[JKJenn]

Disclosure: first Jeep and new to off-road travel, so what might be obvious to many, is not to me

This spring I installed the Gobi Stealth, RR XHD front bumper with a Warn M8000, and a AEV 2.5" Dualsport lift, and changed out my tires to stock Rubicon tires. My vehicle is an automatic. My gas mileage is as expected, poor. Apart from removing any of the above components and regearing (too much money at the moment), any suggestions for improving gas mileage? I will be driving cross country to Colorado and Utah where I will do some overlanding late this summer and would like to try to do my best to get the best mileage I can while making the cross country trek. I believe I am running my current tire pressure around 36 psi.

 

[Rynomar]

I don't really know if a lot you can do, but I have been playing around with using 88 octane gas instead of 86 and although the sample set is pretty small so far, I have put about 1,000 miles on with the higher octane fuel and am consistently getting 1 to 1.5 mpg better than with 86 octane.

Also, I am not sure what kind of mileage you are getting, but I have a 2012 JKUR with the 6 speed, 3.5" lift and 37's. I was regularly getting around 15.5 mpg on 86 octane and am now getting between 16.5 and 17. Considering what I have on it though, I am pretty happy in either case.

Enjoy the trip and let me know if you come up with any other ideas!

 

[Dan Grec]

The best things you can do are:

1) Drive slower. Wind resistance requires more energy than anything else, and it increases with the cube of velocity. Driving at 55 instead of 70 will make a noticeable difference.
2) Accelerate smoothly and slowly, and don't try to hold too much speed up hills.

Other than that, the standard "It's a Jeep" disclaimer applies.

-Dan

 

[JKJenn]

I don't really know if a lot you can do, but I have been playing around with using 88 octane gas instead of 86 and although the sample set is pretty small so far, I have put about 1,000 miles on with the higher octane fuel and am consistently getting 1 to 1.5 mpg better than with 86 octane.

Enjoy the trip and let me know if you come up with any other ideas!

That is worth exploring...keep me up to date on your progress. It will be a couple of months before I go. If it works, it would be worth it for me. I am getting about 12 mpg highway....yuk.

 

[JKJenn]

The best things you can do are:

1) Drive slower. Wind resistance requires more energy than anything else, and it increases with the cube of velocity. Driving at 55 instead of 70 will make a noticeable difference.
2) Accelerate smoothly and slowly, and don't try to hold too much speed up hills.

Other than that, the standard "It's a Jeep" disclaimer applies.

-Dan

Yeah, I am not sure, seriously, that I have the discipline to drive 55 mph from Pittsburgh to Grand junction That would add a few hours to the trip for sure, although it might be worth it.

What should I run the tire pressure at for highway driving? The stock Rubicon tires are slightly bigger than the Sahara tires. Do I follow the tire pressure for the Sahara, anyway?

 

[Rynomar]

Driving slower definitely helps too. If you are up for it, I think it is a pretty good excuse to stick to back roads rather than the interstate, when you can, but I also understand how long that drive is!

As for tire pressure, I would personally just chalk them to determine the best pressure to run them at and stick with it. You will get a little better mileage with them overinflated, but the tires will wear unevenly and wear down much faster. Really not worth it for the minimal gain you would get.

 

[Dan Grec]

Driving slower definitely helps too. If you are up for it, I think it is a pretty good excuse to stick to back roads rather than the interstate

Whenever I'm in the US I intentionally stay off the interstates. I drove from Canada to Mexico and the only interstate I hit was I-5 for the last few kms before Mexico.

There are so many amazing two lane highways that go through all sorts of interesting places.

-Dan

 

[JKJenn]

Whenever I'm in the US I intentionally stay off the interstates. I drove from Canada to Mexico and the only interstate I hit was I-5 for the last few kms before Mexico.

There are so many amazing two lane highways that go through all sorts of interesting places.

-Dan

I would be all for that, but we have limited vacation time. Some year, I will take a trip where I go from Pittsburgh to the Southwest, taking little to no interstates, though.

 

[Ryanmb21]

What MPG are you currently getting?

I called BFG recently to ask them what PSI I should run my new LT265/70/17 Load C All Terrains, they consulted their tables after looking up the weight of my vehicle and recommended 46-50 PSI. This was much higher than the 35 PSI that was recommended on the 4runner forum that I frequented. Perhaps you could increase the PSI?

 

[Longtallsally]

The rack is what is killing you. I'm going to tow a trailer before i put a rack on based on my research. I just finished driving from OH to CA with quite a few hundred miles off road and ended up at a bit over 18mpg. This is a bone stock '12 Rubicon 4 door loaded with 2 people a big dog and a few hundred pounds of gear. Over 70 mph and the mileage drops to below 18- add a cross wind and it will get to 16 real quick. At 65 mph and moderately flat driving I approached 21 mpg every time. I also live on the cruise control when on pavement.

Take back roads and keep it to 55 and you'll do better assuming all the other good advice here has been followed.

 

[Septu]

The big thing is slow down. Went up to Dawson the other weekend. 540 km each way. On the way up I kept the speed at 100kph/60mph and made no attempt to hold it on the hills (the moment it dropped a gear I cancelled the cruise ctl and slowed down). Prior to removing the front panels for the last 100 miles, I averaged ~19.5 MPG (as per the dummy gauge). Seeing how it was pretty windy I was content with that. Pulling the panels shot the mileage way up and I ended up with 18.1MPG hand calculated at the end.

On the way home I did 140-150kph (90mph?) for the first 160 km, and my mileage was 12.9 (hand calculated). The remaining 430km I did 120-140kph (70/80 mph?) and averaged 14.3 MPG.

Now sure I saved perhaps an hour (we were really moving) and did the trip in around 5 hours instead of the 6 hours it took me heading up there... however that hour cost me ~30% more in gas (and gas up there wasn't cheap - 1.58/5.98 per gallon). I'm not complaining, but when I go south this summer (6000 km trip), I'll be sticking the cruise control at 55/60 (depending on the highway), and enjoying the drive. Sure I could do it a bit faster, but when you're talking about a 37 hour drive or 44 hours... does it really matter? Its a long *** drive either way.

 

[Mel.Specs]

What MPG are you currently getting?

I called BFG recently to ask them what PSI I should run my new LT265/70/17 Load C All Terrains, they consulted their tables after looking up the weight of my vehicle and recommended 46-50 PSI. This was much higher than the 35 PSI that was recommended on the 4runner forum that I frequented. Perhaps you could increase the PSI?

It makes sense. The manufacturer recommends a tire pressure based on the weight of the vehicle as it rolls off the line. With the addition of overland accessories (bumpers, winch, racks, rtt, fridge, h2o, fuel, etc.) it increases the vehicle weight dramatically. I have been adjusting my air pressure between the 40-45 PSI range. The results are still pending.

 

[Mel.Specs]

The rack is what is killing you. I'm going to tow a trailer before i put a rack on based on my research. I just finished driving from OH to CA with quite a few hundred miles off road and ended up at a bit over 18mpg. This is a bone stock '12 Rubicon 4 door loaded with 2 people a big dog and a few hundred pounds of gear. Over 70 mph and the mileage drops to below 18- add a cross wind and it will get to 16 real quick. At 65 mph and moderately flat driving I approached 21 mpg every time. I also live on the cruise control when on pavement.

Take back roads and keep it to 55 and you'll do better assuming all the other good advice here has been followed.

The big thing is slow down. Went up to Dawson the other weekend. 540 km each way. On the way up I kept the speed at 100kph/60mph and made no attempt to hold it on the hills (the moment it dropped a gear I cancelled the cruise ctl and slowed down). Prior to removing the front panels for the last 100 miles, I averaged ~19.5 MPG (as per the dummy gauge). Seeing how it was pretty windy I was content with that. Pulling the panels shot the mileage way up and I ended up with 18.1MPG hand calculated at the end.

On the way home I did 140-150kph (90mph?) for the first 160 km, and my mileage was 12.9 (hand calculated). The remaining 430km I did 120-140kph (70/80 mph?) and averaged 14.3 MPG.

Now sure I saved perhaps an hour (we were really moving) and did the trip in around 5 hours instead of the 6 hours it took me heading up there... however that hour cost me ~30% more in gas (and gas up there wasn't cheap - 1.58/5.98 per gallon). I'm not complaining, but when I go south this summer (6000 km trip), I'll be sticking the cruise control at 55/60 (depending on the highway), and enjoying the drive. Sure I could do it a bit faster, but when you're talking about a 37 hour drive or 44 hours... does it really matter? Its a long *** drive either way.

That Pentastar V6 also has an advantage over the 3.8L. I heard or read somewhere the numbers on a Hemi swap are a little better also.

 

[Septu]

That Pentastar V6 also has an advantage over the 3.8L. I heard or read somewhere the numbers on a Hemi swap are a little better also.

True. However I got very similar numbers with my 07 (moded out, but had 3.21 gears) if I kept it to 100/60 (and actually got better numbers on several occasions). But then I was under geared then, while I'm over geared now. But that was more to point out the vast differences speed plays into the mileage.

 

[voodoojk]

Just something to ponder..Did you use a tuner ( like aev pro cal) to adjust the new tire size? ( rubi stk tires are 32") not sure what size you were running but that will make a difference with shift points ( if auto), milage etc. If it is off you will get false milage readings.

Have a safe trip to CO...im on the western slope in glenwood spgs.