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rickinAZ

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My 2021 JLURD is about two states away and steaming (I wish) towards Phoenix.

My window sticker reads: 21 City, 26 Highway, 23 combined. That's 2 MPG less combined than 2020s with highway taking a bigger hit (3 MPG) than city. Originally the theory was a 4.10 final drive ratio on the 2021s versus 3.73 on the 2020s, but one of the first 2021 diesels delivered has 3.73 ("just less than four axle turns when I completely spin a rear wheel").

So where did the 2 MPG go? I didn't order the diesel for economy, but it is a nice side benefit.
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Compression-Ignition

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Don't lose heart just yet. Wait until you get your ass in the seat and see what's what at that point.

Could be they changed the tune on it or something. Could be that the mpg testing was slightly different.

My wife's 3.0L Wrangler gets about 24-26 mpg hand calculated on 37s at 60-75 mph. Stock 3.73 gears. City is more like 17-20.

Just wait and see is all I'm saying.
 
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JLURD

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Would be nice to know if this is something the folks in Ann Arbor tested, or if they accepted the in-house testing of Jeep. My guess is the anti-diesel bias of the Ann Arbor crew is involved.
 

WXman

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It's probably a more accurate number. Perhaps they retested it, or tested it in a more real-world trim level? Perhaps they saw how Ford is being repeatedly sued for fudging the numbers on their EcoBust family of engines?

In any case, the lower numbers are more accurate based upon what I'm seeing. I haven't once reached window sticker rating. And, the dash display is always 1.0 to 1.5 MPG optimistic as well, which was never the case on my gas FCA vehicles.
 

GearWhore

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I noticed the lower ratings a couple weeks ago when my window sticker published. My guess is likely more accurate testing, more real-world feedback, or something similar.

My 2018 WK2 Trailhawk ecodiesel never could quite make the highway mpg on the sticker no matter how gingerly I drove it. I get that is an average, but my vehicle seemed to be below average in that department. So I gave it bigger, more aggressive tires and skid plates, and just enjoyed the powertrain while waiting for a rumored JLURD. :rock:
 

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rickinAZ

rickinAZ

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A new headscratcher.
Virtually none of us bought these diesels exclusively for the fuel economy, but if I had, I’d feel like the victim of a bail & switch. They so touted the mileage and then very quietly it went down 10%. I can picture a Jeep executive studying his fingernails and saying “ oh...did the rating go down? I really hadn’t noticed”

Come on Jeep, man up. We’ll still love you
 
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JLURD

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It's probably a more accurate number. Perhaps they retested it, or tested it in a more real-world trim level? Perhaps they saw how Ford is being repeatedly sued for fudging the numbers on their EcoBust family of engines?

In any case, the lower numbers are more accurate based upon what I'm seeing. I haven't once reached window sticker rating. And, the dash display is always 1.0 to 1.5 MPG optimistic as well, which was never the case on my gas FCA vehicles.
There are plenty of folks on here reporting numbers right at the ‘20 EPA average or better. The % delta between my ‘18 3.6 and ‘20 3.0 fuel economy is higher than predicted by the EPA numbers, despite substantially worse aero and rolling resistance on my 3.0 setup.
 

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JLUfan

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My bet is they tested a Overland or Sport last year and applied that to all trim levels. They then saw the tire size and gearing? difference and tested a Rubicon specifically and applied the updated mileage for that trim level for 2021. The EPA now lists two fuel economy ratings for the 2021 diesel. One identical to last year, and one with this “updated“ figure.
 

WXman

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There are plenty of folks on here reporting numbers right at the ‘20 EPA average or better. The % delta between my ‘18 3.6 and ‘20 3.0 fuel economy is higher than predicted by the EPA numbers, despite substantially worse aero and rolling resistance on my 3.0 setup.
Unfortunately none of those reports are trustworthy, which is why we have to turn to Fuelly.com to get the truth because those hand calculations take the guesswork out. And what we're seeing so far after nearly 40,000 miles of combined real-world data is a MPG figure around 20.7 MPG. This lines up pretty well with the 21 MPG I'm averaging also.

That's nowhere close to the 24 on the window sticker.
 

SolarWizard

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Unfortunately none of those reports are trustworthy, which is why we have to turn to Fuelly.com to get the truth because those hand calculations take the guesswork out. And what we're seeing so far after nearly 40,000 miles of combined real-world data is a MPG figure around 20.7 MPG. This lines up pretty well with the 21 MPG I'm averaging also.

That's nowhere close to the 24 on the window sticker.
From the diesel section. Includes 20 miles of offroad driving
Jeep Wrangler JL 2021 Rubicon EcoDiesel EPA rated MPG drops (per window sticker) 82BBA477-3A9A-4B89-804B-8FDB91EFEF88
 

Oilburner

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Unfortunately none of those reports are trustworthy, which is why we have to turn to Fuelly.com to get the truth because those hand calculations take the guesswork out. And what we're seeing so far after nearly 40,000 miles of combined real-world data is a MPG figure around 20.7 MPG. This lines up pretty well with the 21 MPG I'm averaging also.

That's nowhere close to the 24 on the window sticker.
Hell I average almost 23 and usually pull a small trailer, up & down 11% grade every time I leave the house. I am just over 10K.
 

AZ-Chris

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I've been averaging about 24 mpg in around-town driving in the Phoenix metro area . . . the photo posted above by SolarWizard is from my recent return trip from Colorado . . . I could have improved those numbers if I hadn't done the Schnebly Hill Road trail in Sedona and not been a lead foot when traversing the uphill grade over the San Francisco Peaks in Flagstaff. DEF consumption is still a bit suspect . . . I'm down another 1/4 tank in the last 1,000 miles.
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