2 MPG drop from Mopar Lift with stock tires?

unsavory

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My JLUR only has about 1500 miles on it, but I swear I was getting 18.1 MPG before installing the Mopar lift. And now it is dropped to 16.3, which is about a 2 MPG decrease from just the lift.

I have not yet upgraded the tires to 35".

I know lifts do affect gas mileage, but I was very surprised to see this big of a drop. Is this normal? I haven't had an alignment done yet, because it otherwise drives great. Tracks perfectly straight, no wondering or other issues.





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wolfdog

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Sounds about right...about 10% for every inch over a 1" lift. So they say, who ever "they" are. Add bigger and more aggressive tires more!

Have fun!

Go Jeep!!!
 
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unsavory

unsavory

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That's amazing. Okay, what is the physics behind this? Why would lifting it lower MPG by that much? I can understand that there would be slightly more wind resistance due to the lifted height exposing more of the underbits, but 10% per inch?

Surely there must be some other factor at play?
 

DaltonGang

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Doesn't surprise me. I dont think we bought these for their gas mileage.
 

Paluss

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I would recommend going through several tanks of gas before you come to your final conclusion, since temperature, wind and other things (winter blend gas?) can have an effect. Raising a vehicle does make it less aerodynamic...
 

JLJoy

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Doesn't surprise me based on my mileage. I have the Rubicon Unlimited with MOPAR lift, 35" Cooper AT3 XLT tires and Fuel Trophy Wheels. Seem to average 15 to 16 on highway running 65 to 70. Typically get about 17 in town. The wind drag kills these things on the highway. Had to hustle out to western Kansas last week to get my son and his wife out of snow drift in blizzard. Leaving Wichita driving into a 25 to 30 mph head wind, I was getting 10 to 11 running 75. Glad we don't buy these for economy purposes.
 

CJ-ING-RJ

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Be happy with what you are getting... I'm in a stock JLUR and I'm averaging 15.2. I've owned several Jeeps and I understand we are driving a brick with big heavy tires but 15mpg in today's age is just plain stupid. Also I do not have a heavy right foot.

Screenshot_20190103-205941_Fuelly App.jpg
 

wolfdog

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One trip meter reading ("B") before I "reset" it by mistake since picking up JLUS... Miles 8940, MPG 20.8 My trip meter MPG is of about 2/10 from doing MPG by math method. Better than my 2012 JKUS by about 2 MPG, same driving but 10mph less speed. I never drove the JKU above 60mph and a bit, My mileage on the JLU for that 8940 was a commute of 60 miles round trip 90% highway and at 70ish mph and a couple 500mile trips mostly highway. If I stick to 60mph with the JL my mileage is 23 or more. So overall it's much better that the '12 JK!

My wife has stolen our JLU for her own use ("oh I love it") and now most around town driving and gas mileage has dropped way down 16/17 at best!

As said above, Wranglers are as streamlined as a brick and it's heavy and most folks don't by a Jeep Wrangler and expect Hybrid mileage! A little better would not hurt but I think the JL has improved Wrangler mileage a bit. Mostly I think it's the 8 speed auto that's making the diff? I can't speak for the 6 speed!

Oh ya to stick to the thread the lift does have almost all to do with drag. Add big tires to look better and ya I suppose off road better if you'll do a lot of that, will rob another 10% or more depending how big bold the tires! If you are going to modify a lot, like heavier steel bumpers winches and etc. better put MPH way back on the back burner, good luck!

Go Jeep!!!
 

TIDALWAVE

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That's amazing. Okay, what is the physics behind this? Why would lifting it lower MPG by that much? I can understand that there would be slightly more wind resistance due to the lifted height exposing more of the underbits, but 10% per inch?

Surely there must be some other factor at play?
More air can flow under the body causing more frictional drag as it whips against the suspension, etc. Look at photos of the underbodies of most supercars...close to totally smooth. I am going to lift my Rubi and install full under body skid plates.
 

WXman

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I did a 2.5" lift AND 34" KO2s and lost 2 MPG hand calculated with Fuelly over a 9,000 mile trend. So I wouldn't expect a lift alone to lose 2.5, but I suppose anything is possible.
 

wolfdog

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More air can flow under the body causing more frictional drag as it whips against the suspension, etc. Look at photos of the underbodies of most supercars...close to totally smooth. I am going to lift my Rubi and install full under body skid plates.
This may help but will the "smoothness overcome the weight of the full skid plates? Aluminum?

Go Jeep!!!
 

powderboarder

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Wow. I just picked up my JLR last week and have an average of 19.2 MPG so far and constantly see the instant MPG hovering at around 30 MPG. Driving daily country roads at about 45-55 MPH.

I am sure it will start going down once I start doing mods, but this thing is amazing so far!
 

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Sounds about right...about 10% for every inch over a 1" lift. So they say, who ever "they" are. Add bigger and more aggressive tires more!

Have fun!

Go Jeep!!!
Really....

I was getting about 22+ on the highway with my all stock JLU Sahara and once I went to a 2.5” boost and 315 KO2’s my MPG dropped to about 18-19
 

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