2018 Jeep Wrangler Rubicon Diesel Mule Spied with DEF Tank

The Great Grape Ape

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Yea the fuel economy is nice, but the TQ, increased range, and towing capacity..
Torque is undeniable, and nice, would prefer it delivered with gasoline (just because diesels hate the cold I work & play in), but all of those are possible advantages of diesel in the current expected JL offerings.
Torque though is the only one that will be significant, and it's significance/benefit will depend on what it's attached to and how it's programmed for delivery. Even the Pentastar's torque delivery is hampered by the 1,500 RPM torque converter characteristics, so most improvements get minimized by the JK's drivetrain currently (automatic is crippled , manual is too weak).

Range won't be that impressive unfortunately because it's still pushing a heavier [meaning diesel vs Pentastar as well as diesel added weight possibly more than JL vs JK savings which is expected to be ~200lbs not half a ton] brick into the wind. It will be slightly better, but still pale in comparisson to things like the Cherokee or Subarus, etc. Maybe 100miles more, but likely barely 100KMs more.

If range has ever been an issue, then a 5,10,15 gallon in-line fuel tank add-on would offer far more range at a fraction of the cost. Just like many Overlanders crow the benefits of the Defenders' diesel for overlanding, in stock formation it has less range than a petrol JKU, only by making it a 100+L tank with the optional reserve tank add on does it out-distance the JKU, and again, only just barely (it actually still loses to a JKU CRD again just barely which shows the minimal swing of the 2.8L CRD in a JKU).

Towing capacity is likely to be minimally affected by diesel on the JL, mainly because the limits will be chassis & suspension based not torque based. Now on the JT there is definitely more opportunity for a better tow/payload-capable setup, but even in the RAM, the Ecodiesel and Pentastar are only 1,000 lbs apart (with the same 3.55 axle ratio, 1,800 with the Ecodiesel's 3.92) and that's mainly because like the axle weakness the Pentastar got the weaker 845RE transmission instead of the 8HP70 of the Ecodiesel. Same for same, I doubt the gulf in capabilities would be that big, especially if it get the proper PUG update expected adding EGR etc and boosting torque primarily over existing Pentastar in JK.
I also doubt we'll see above 7,500 lbs on the JT, more likely 6,000lbs to beat the Ridgeline, Tacoma, Canyon numbers, and possilly 7,200 to play with the Armada (based on Titan) and other cottage runabout towing vehicles.

There's no doubting the benefits of diesel in certwin applications, but the comparative amount is a little more variable than people make it out to be.





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AWD

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Ecodiesel is unlikely to get a manual transmission without seriously crippling it for two reasons;
A) Torque output is way above the ratings for current 6-speed 200+ NM too much) and all other 6-speed option in its area (70NM beyond the specs for the Mustang/Camaro/Cadillac NV in Camaro guise [which maxes at 500NM but at the cost of tighter gear spread and lower first gear ratio])
B) Fuel efficiency (and maybe towing) will be the mainfocus of the diesel, despite enthusiasts other reasons; and the 8-speed auto with its large spread with multiple taller overdrive gears (escpecially vs an NV6) has better efficiency and is more predictably efficient in real world, also that 8-speed also improves towing numbers as well both for handling and efficincy under load.
Noticed that the Ram 2500 has a turbo diesel + manual combination. Its G56 6 speed manual can deal with that 900 lb-ft torque output from the Cummins turbo diesel. So I'm guessing that 6 speed doesn't fit in the Wrangler or has wrong gearing for it? Otherwise why not just mate that to the EcoDiesel and call it a day? :)
 

orey22

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Noticed that the Ram 2500 has a turbo diesel + manual combination. Its G56 6 speed manual can deal with that 900 lb-ft torque output from the Cummins turbo diesel. So I'm guessing that 6 speed doesn't fit in the Wrangler or has wrong gearing for it? Otherwise why not just mate that to the EcoDiesel and call it a day? :)
Which gives us a glimmer of hope, somehow, someway, a diesel + manual pairing will make it into the Wrangler. I just can't stomach an automatic, but that's all personal preference.
 

The Great Grape Ape

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Noticed that the Ram 2500 has a turbo diesel + manual combination. Its G56 6 speed manual can deal with that 900 lb-ft torque output from the Cummins turbo diesel. So I'm guessing that 6 speed doesn't fit in the Wrangler or has wrong gearing for it? Otherwise why not just mate that to the EcoDiesel and call it a day? :)
Actually the Cummins is detuned for the manual in the Ram the G56 can only handle about 850+NM/650+lbft, but still more than enough for the Ecodiesl. The 1st gear ratio is fine, it's better than the current NSG370, and the spread is about the same the overdrive is higher (ie closer to 1:1 which is less beneficial), however the Getrag transmission is heavy as F and big too, similarly so is the Tremec 6060 which can also handle 800+ NM, but is also big & heavy. Not a great match for the Wrangler which is why I mention the Tremec 3160 transmission, which is the only one with pretty good torque support and not a giant hunk of metal, but would be challenged by the full torque of the Ecodiesel, though is closer than I remember 20NM over not 70.

Of note, it also just so happens to allow two configurations of the shift pattern the default similar to the spy photos last year, and the alternate 'upside down' pattern which just so happens... to match the current NSG370 pattern in the JK.



http://tremec.com/anexos/File/TREMEC_TR-3160.pdf

That's the current challenge rellying on what's available, and while there are some interesting options out there including 7-speed options, many are transaxle assemblies or not good fits for part time 4wd.

As much as the NSG370 has its faults, it was very small & light, had a good 1st gear, pretty good spread, and OK torque support for the engines of its era.
 

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Torque is undeniable, and nice, would prefer it delivered with gasoline (just because diesels hate the cold I work & play in), but all of those are possible advantages of diesel in the current expected JL offerings.
Torque though is the only one that will be significant, and it's significance/benefit will depend on what it's attached to and how it's programmed for delivery. Even the Pentastar's torque delivery is hampered by the 1,500 RPM torque converter characteristics, so most improvements get minimized by the JK's drivetrain currently (automatic is crippled , manual is too weak).

Range won't be that impressive unfortunately because it's still pushing a heavier [meaning diesel vs Pentastar as well as diesel added weight possibly more than JL vs JK savings which is expected to be ~200lbs not half a ton] brick into the wind. It will be slightly better, but still pale in comparisson to things like the Cherokee or Subarus, etc. Maybe 100miles more, but likely barely 100KMs more.

If range has ever been an issue, then a 5,10,15 gallon in-line fuel tank add-on would offer far more range at a fraction of the cost. Just like many Overlanders crow the benefits of the Defenders' diesel for overlanding, in stock formation it has less range than a petrol JKU, only by making it a 100+L tank with the optional reserve tank add on does it out-distance the JKU, and again, only just barely (it actually still loses to a JKU CRD again just barely which shows the minimal swing of the 2.8L CRD in a JKU).

Towing capacity is likely to be minimally affected by diesel on the JL, mainly because the limits will be chassis & suspension based not torque based. Now on the JT there is definitely more opportunity for a better tow/payload-capable setup, but even in the RAM, the Ecodiesel and Pentastar are only 1,000 lbs apart (with the same 3.55 axle ratio, 1,800 with the Ecodiesel's 3.92) and that's mainly because like the axle weakness the Pentastar got the weaker 845RE transmission instead of the 8HP70 of the Ecodiesel. Same for same, I doubt the gulf in capabilities would be that big, especially if it get the proper PUG update expected adding EGR etc and boosting torque primarily over existing Pentastar in JK.
I also doubt we'll see above 7,500 lbs on the JT, more likely 6,000lbs to beat the Ridgeline, Tacoma, Canyon numbers, and possilly 7,200 to play with the Armada (based on Titan) and other cottage runabout towing vehicles.

There's no doubting the benefits of diesel in certwin applications, but the comparative amount is a little more variable than people make it out to be.
I understand your points but disagree with you on some of them.

If you simply look at the Grand Cherokee, you will see the diesel in that (which if rumors are correct would be the same in the JL) vs the Pentastar, you can see the diesel has a BIG advantage. Better fuel economy, better range (almost 800 miles on a tank), and better towing. The Pentastar motor is garbage IMO. I hate it, and its my #1 dislike on my current JKU. Fuel economy with a lift is crap, its noisy (sounds like its going to fall apart at full throttle), and is annoying on the highway (trying to hold it above 70 mph is work). Its simply underpowered for the job. Yes it does the job, but its just barley adequate.
 

The Great Grape Ape

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I understand your points but disagree with you on some of them.

If you simply look at the Grand Cherokee, you will see the diesel in that (which if rumors are correct would be the same in the JL) vs the Pentastar, you can see the diesel has a BIG advantage. Better fuel economy, better range (almost 800 miles on a tank), and better towing.
Better, yes, but significantly so, not really. And it's not 'nearly' 800, it's 730 according to FCA's optimistic numbers which is significantly lower. If it was 770 I'd give it to you but it won't significantly beat that unless hyper-mileing, which isn't a Wrangler trait so again stretching numbers instead of being more realistic about them.

The MPG aren't realistically comparable to a GC, but let's use the best case scenario (including FCA's optimistic MPG numbers, since the EPA has pulled the GC's EcoDiesel rating) to illustrate my point.

The fuel tank is 24.6 Gallons.
FCA Pentastar MPG 22/24/29
FCA EcoDiesel MPG 24/26/34

So, if you were to be the most optimistic with all highway driving you are talking about 123 miles more, and that's with a tailwind downhill according to the reviews. It's still the best of the bunch but most 'urban' reviewers were seeing 30MPG out of the Eco and 28 out of the Pentastar. The off-road MPG performance is a complete mystery, and even more so again for a solid axle brick, where that delta is likely reduced further still.

However comparing even that optimistic 123 miles to the overland distance of even just a 10 gallon extended fuel tank of 290 miles for about 20% the cost, or better yet the 20Gal/68L doubling that distance for about the same price.
That's my point on the range issue for overlanding. MPG is better, but it will likely be less than 100miles in a JLU (likely closer to 75) and less in a JL due to smaller tank size, especially if the JL(U) keep the 22.5/18.5 Gallons of the JK(U).

Towing is only 1000lbs different on the Grand Cherokee, that's not as significant as it sounds on paper, and again it will be limited by chassis. Better yes, better for towing on the right platform, sure, but on a Wrangler? Not likely to be as big a gulf, and more likely to cost you payload capacity at the cost of towing if all things are equal.

The Pentastar motor is garbage IMO. I hate it, and its my #1 dislike on my current JKU. Fuel economy with a lift is crap, its noisy (sounds like its going to fall apart at full throttle), and is annoying on the highway (trying to hold it above 70 mph is work). Its simply underpowered for the job. Yes it does the job, but its just barley adequate.
Nah, that's a pretty big helping of haterade there, not being objective about it in the least, especially compared to the far weaker options both historically and currently in the segment.
Engine/Exhaust Sound can be shaped with a good exhaust (or soup can. ;) ) so that's a meh, and for that aspect I'd prefer a Hemi rumble to the chug chug of a diesel if we're gonna talk about stuff like sound... And... likely for 'equally significantly' cheaper than the EcoDiesel again.

The MPG and 70 mph issue has less to do with the engine than it does with the mediocre transmissions that the Pentastar is attached to, even the CRD diesel does poorly compared to other applications thanks to that aspect. With the 8-speed in there it'll likely brighten up greatly both for bigger tires and for highway performance thanks to the wider ratio spread, and the much MUCH shorter first and second gear (shorter than the NSG370 even) while having two more efficient overdrive gears. As mentioned above the new manual's characteristics/performance remains a mystery.

Like I said, the Ecodiesel will undoubtedly (almost undoubtably) be better for those three aspects, but the level of that 'better' is usually much less than people give it credit for, especially when strapped inside the constraints of the Wrangler.

I'm fine with the EcoDiesel it's a great engine and definitely should be there, but so should a Hemi for pretty much all the Wrangler-centric arguments (no one buys it for MPG). My issue is people fetishize the EcoDiesel and oversell it's benefits, whereas the reality is far less compelling and just another nice option in the long run, not the one and only ideal option.
 

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Have there ever been any definitive studies of MPG between a JKU/JK with top and doors on, and MPG wit too and doors off ?

Any consensus on fuel savings ?

I'm imagining an EcoDiesel JLU in the summer, topless&doorless, getting well upwards of 800milss per tank.
 

The Great Grape Ape

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Doubtful.
While the doors and roof on a JLU likely amount to about the same ~400lbs savings of a JKU despite the active attempts at reduction in those areas, it's still not very aerodynamically efficient. S,o I doubt it would add 70 miles to the GC's numbers all with 2 gallons less fuel in the JLU.

I would expect a low 600 miles figure (~625) to be the magic numbers if there aren't drastic efficiency changes. And at least half of that number would be due to the transmission switch improvement in conjunction with diesel benefits.
 

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Actually the Cummins is detuned for the manual in the Ram the G56 can only handle about 850+NM/650+lbft, but still more than enough for the Ecodiesl. The 1st gear ratio is fine, it's better than the current NSG370, and the spread is about the same the overdrive is higher (ie closer to 1:1 which is less beneficial), however the Getrag transmission is heavy as F and big too, similarly so is the Tremec 6060 which can also handle 800+ NM, but is also big & heavy. Not a great match for the Wrangler which is why I mention the Tremec 3160 transmission, which is the only one with pretty good torque support and not a giant hunk of metal, but would be challenged by the full torque of the Ecodiesel, though is closer than I remember 20NM over not 70.

Of note, it also just so happens to allow two configurations of the shift pattern the default similar to the spy photos last year, and the alternate 'upside down' pattern which just so happens... to match the current NSG370 pattern in the JK.



http://tremec.com/anexos/File/TREMEC_TR-3160.pdf

That's the current challenge rellying on what's available, and while there are some interesting options out there including 7-speed options, many are transaxle assemblies or not good fits for part time 4wd.

As much as the NSG370 has its faults, it was very small & light, had a good 1st gear, pretty good spread, and OK torque support for the engines of its era.
Hrm yes forgot about weight. And Jeep seems real focused on the weight (reducing it) on the JL.

The Tremec 3160 would seem to work since it's rated up to 425 LB-FT (576 Nm) capacity and the Ecodiesel produces 420 lb-ft in the Ram 1500. But I've only see RWD applications (Camaro, Mustang) for the Tremec 3160, does it actually have 4WD application?
 

Dackel

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Have there ever been any definitive studies of MPG between a JKU/JK with top and doors on, and MPG wit too and doors off ?

Any consensus on fuel savings ?

I'm imagining an EcoDiesel JLU in the summer, topless&doorless, getting well upwards of 800milss per tank.
Aerodynamics has a much greater proportional impact on MPG than weight. In other words the weight you are saving by going topless and doorless is nothing compared to the extra drag created when you remove those parts. The goal of engineers is to get the wind to flow above, around and through the vehicle with as little resistance as possible and when you take the doors/top off it disrupts the airflow and the problem is exponentially worse the faster you're driving.

So the answer to your question is doors and top on is the best for extra mileage, but it will make little difference unless you are constantly on the highway at speeds over 50-60 mph. At that speed on level pavement, the weight of your vehicle will have little effect on mpg but aerodynamics will matter a lot.

If you've ever been in a Jeep with the doors/roof off on the highway this will be very obvious to you since the faces and eardrums of everyone inside will be creating drag LOL, and as the driver you will have to use more gas to maintain the same speed.
 

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My TJ gets much better power AND mileage with the top off...

Just sayin
 

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Hrm yes forgot about weight. And Jeep seems real focused on the weight (reducing it) on the JL.

The Tremec 3160 would seem to work since it's rated up to 425 LB-FT (576 Nm) capacity and the Ecodiesel produces 420 lb-ft in the Ram 1500. But I've only see RWD applications (Camaro, Mustang) for the Tremec 3160, does it actually have 4WD application?
Tremec 3160 only has RWD applications so far on the Camaro, Mustang and Cadillac ATS.
 

The Great Grape Ape

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Tremec 3160 only has RWD applications so far on the Camaro, Mustang and Cadillac ATS.
That's the current applications, but they also mention it's made for SUV and Light truck applications in their other literature about the overall platform, so I wouldn't be so sure it's limited to just RWD only, especially since a Wrangler implementation would likely outsell all of those other 3 combined.

There are many transmission described as RWD, that have ended up in 4WD vehicles like AY6 in the Tacoma and ZF 6-53 in the LR Discovery.

There are other options out there of course, but like the above or the Getrag, 238 or 217 they're either too heavy or don't handle enough torque, and often have poor ratios and spread.

We'll find out when it launches, but there is little point in replacing the NSG 370 with something that doesn't address both those issues.
 

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I'm worried they may pull the plug on the diesel if they dont get this EPA thing straightened. The diesel option used to say late availability on their site if you tried to build a GC....not its not even listed as an option at all. Still says late availability for the Ram though.
 

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