Eco diesel or 3.6 gas??

[Hootbro]

First, I want to say that I'm not disagreeing with you, the FAD is definitely another point of failure, and not a benefit on an individual level.

Out of curiosity, I made some assumptions and ran some rough numbers. Here we go;

Let's say the average JL/JT lifespan is 100k miles, and it averages 15.0 mpg without FAD. During this average lifespan, these jeeps will use 6,667 gallons of fuel.

Same assumptions, but with the addition of FAD, these JL/JT's get 15.1 mpg. During this average lifespan, these jeeps will use 6,622 gallons of fuel. So the FAD at 0.1 mpg saves each Jeep about 45 gallons of fuel over it's lifetime.

For the 2021 model year, Jeep produced about 300k JL/JT's. So for the 2021 model year, the addition of FAD saves 13,500,000 gallons of fuel.

If the gallon of fuel averages $3.00 over this period, that is $40,500,000 spent on something besides wasted fuel.

This isn't to argue for or against FAD, I just think the numbers are interesting!

I think your reply sums it up pretty well. CAFE standards are not just averaging MPG across models of a given brand, but there is also a formula that factors in and gives credit for how many of particular model is sold.

So those tenths of a mile gain here or there add up and the automakers get credit regardless if those features are disabled, removed or not used at the end user level.

What we consider annoying or inconsequential, the auto makers have to squeeze everything they can at manufacture as built or be fined for failing to meet ever increasing CAFE requirements.

Sponsored

 

[KW80]

My diesel JT is driven on flat terrain with a light foot.
The gas JL was in hilly AZ with a light foot.
Both KO2s at about 40#, factory gearing.

My results are not that unusual once you start looking around to what others are posting.

I think however I may have to test drive a diesel from a local dealership just to see for myself. I drove mine off the lot w 5 miles on the odometer and had the tires swapped to 37s before 70 miles, but I do recall for that little bit I was averaging 22 on mostly hwy miles with the factory falkens.

I caught a blip on a YouTube video where it said the FAD was for fuel mileage savings. I wonder if the bugaboo is in that?
There seems to be two different groups of diesel JT owners: those that can modify their Jeeps any which way and still get over 25 MPG, and those who struggle to get 20.
I'm not yet convinced that the other group isn't prevaricating to make themselves feel better about their choice.



My last vehicle was an '06 f150 that I drove off the lot new and put 281,000 mi on the notorious Triton 5.4 with no engine work and it still runs great. I drive my vehicles like I want them to last forever while getting the best mileage they possibly can, in flat Florida. The way I drive is not the issue and I'm not the only one getting substandard fuel mileage from my EcoDiesel JT.
I have been hand calculating every tank of gas, as a matter of habit since I bought my last truck new, and consistent with other reports, hand calculations are typically less than what the Jeep shows by about 1½ MPGs.

I hand calculate as well and routinely get 450 miles per tank, so my experience with fuel economy is pretty much as advertised on a mostly stock Sport S with 285/70 BFG KO2s. Only when wind is extreme do I dip significantly down below 25mpg on the highway. If you briefly drove in stock configuration and put on 37s almost immediately, not sure how it is fair to say that your EcoD JT doesn’t get near the stated MPG, you hardly drove with the stock setup.

 

[Pescatoral Pursuit]

I hand calculate as well and routinely get 450 miles per tank, so my experience with fuel economy is pretty much as advertised on a mostly stock Sport S with 285/70 BFG KO2s. Only when wind is extreme do I dip significantly down below 25mpg on the highway. If you briefly drove in stock configuration and put on 37s almost immediately, not sure how it is fair to say that your EcoD JT doesn’t get near the stated MPG, you hardly drove with the stock setup.

I recently reinstalled my OE wheels and tires for a couple gas tanks and mileage still fell way short.

 

[alpineovernappa]

First time Jeep owner. I HAD to have a diesel. After driving it for 8 months I can tell you:
It doesn't get near the manufacturer's stated mpg.
Most of the time it felt as if it was running in a "detuned" state where full power could not be realized.

I rented a similarly modified 3.6 Wrangler for over a week recently and it matched the MPG numbers my diesel gladdy gets: just under 20.
Acceleration is not as bad as its underserved reputation.

I can't speak to towing capabilities with either.

If you want consistent max power and better than 10-15 MPGs get the diesel and get it tuned.
If you want a respectable driving/ mpg Jeep, get the gas and invest your savings.

I'll echo what others have said- there is a problem with your ED. My sport S ecodiesel in stock form consistently got 30-31mpg for the first 12,000 miles with a rooftop tent and ~500lbs of gear in it. I put a full rubicon suspension and takeoff wheel/tires and with all that, inclusive of the gear and above-cab hardshell RTT I still have never seen an average below 23. To get down to the low 20s mpg I had to do 90mph across west texas. I only have 18k on mine, but I've literally never had a tank average below 23mpg.

 

[KW80]

I recently reinstalled my OE wheels and tires for a couple gas tanks and mileage still fell way short.

I guess that’s the definition of YMMV. On reasonably flat terrain (hills not mountains), without crazy wind (not getting pushed all over the road), and speeds 75mph or below (above 75 the brick aerodynamic penalty multiplies) I chug along at 26-28 mpg all day. Anecdotally I have seen more people with stock (or near stock) EcoD JTs share a similar story to mine than what you are experiencing. Maybe a poll is in order to gather a sample from forum members. Certainly people can still embellish, but it is at least more scientific than recalling from memory comments on multiple different threads.

 

[Akgladiator]

ok here is my take on diesel vs gas on gladiator:
For gas gladiator, stock power is decent if you have at least 4.10 or plan to upgrade higher than that. Once you done, you may feel power is still insufficient, so you may slap a supercharger on it and that will cost another $5k to $8k. However that will put your jeep out of warranty.

For diesel gladiator, you have the extra torque to go with. Yes you have to pay extra $4k for it but the diesel engine is cover by factory warranty.

Diesel definitely has its higher maintenance cost. If you are planning to do force induction on your jeep, i definitely go with diesel option.

 

[Randonexplosion]

Unfortunately my fuel mileage seems to be sub-par averaging a little over 21 (mostly city driving). I just had to refill my DEF tank for the first time at about 2300 miles.

Off topic: how often are you guys getting the exhaust regen message? Mine has been occuring more freuently and it seems to be about every couple hundred miles now. Maybe I need to get a hold of the dealer about the reflash even though it is a 2022 with a build date of 1-22.

 

[Gruffid]

I’ve never seen an exhaust regen message. Mine’s an early 2021 build (picked up just before thanksgiving in 2020)

 

[staying_tuned]

I’ve never seen an exhaust regen message. Mine’s an early 2021 build (picked up just before thanksgiving in 2020)

At 26k miles on my 21’ and same here, haven’t seen a regen message yet but minimum drive is 30 mins at or above 55mph.

@Randonexplosion Typically on delivery the DEF tank is only half full. May explain the low mile need to refill, that or the mostly city driving you mention. Were you at 100% at delivery?

 

[Randonexplosion]

At 26k miles on my 21’ and same here, haven’t seen a regen message yet but minimum drive is 30 mins at or above 55mph.

@Randonexplosion Typically on delivery the DEF tank is only half full. May explain the low mile need to refill, that or the mostly city driving you mention. Were you at 100% at delivery?

Mine was only 3/4 full. A 2.5 gallon jug only got it back to the same after the warning. Is the tank 5 gallons total?

 

[staying_tuned]

Mine was only 3/4 full. A 2.5 gallon jug only got it back to the same after the warning. Is the tank 5 gallons total?

Yep, 5G.

 

[Labswine]

Okay, 2020 Overland (Built May/June 2019, took delivery in July 2019) with 19,5xx miles on it now, and stone stock.

Two recent trips of significant distance, W. Chester PA to northern Michigan and back, calculated fill to fill, average 25+ mpg (the 75 mph stretch in northern MI caused the dash read out to go from low 26s to low 22s and did affect the trip average, calculated fill to fill).

Most recent trip was W. Chester, PA to Raleigh, NC and back. Averaged 26.3 mpg. Both calculated and dash readout.

I did notice that once I crossed the 17K mile barrier, my economy went up significantly as I was averaging mid 23s on the highway and now it's more like low to mid 26s.

Now to my point...diesel vs. gas...you are going to spent about $4K more for the diesel plus the fact that currently (at least here in PA) diesel is $1.20-$1.30/gallon more than gasoline. With the highway fuel economy I am currently getting (plus I average in the low 19s bopping around) and the extra costs associated with the diesel in 1) just getting it and B) the cost of fuel, in my mind just the 3.6L gasser is more than adequate. I do read occasionally that those who are lifted and have the jymungus tires will see the fuel economy advantage with the diesel so there's that but you're still going to pay another $20 or so per fill up than those of us with gassers.

Just my $0.02 ($0.03 Canadian).

 

[Koolcarguy]

Gas for sure, diesel isn’t worth it for the cost of maintenance and repairs, also diesel cost more per gallon.

I guess it depends if you need or want the power? And depends how you drive? My wife gets 30 31 in her stock Rubi Jl and only got 16 18 in her gas jl? The payoff for me is can run 37's and still cruise the hiway at 85 no issues ? Can pull my 3200lbs trailer over I 70 in Colorado doing the speed limit was down to 45 or 50 in the gas model

 

[Koolcarguy]

Does it get cold where you live? The DEF systems frequently fail in cold weather and can be a major recurring problem.

I live in Wyoming had 20+ days -0 and with the wind chill -25 never plugged in my diesel Gladiator parked outside never had 1 issue 25k miles in

 

[Koolcarguy]

Okay, 2020 Overland (Built May/June 2019, took delivery in July 2019) with 19,5xx miles on it now, and stone stock.

Two recent trips of significant distance, W. Chester PA to northern Michigan and back, calculated fill to fill, average 25+ mpg (the 75 mph stretch in northern MI caused the dash read out to go from low 26s to low 22s and did affect the trip average, calculated fill to fill).

Most recent trip was W. Chester, PA to Raleigh, NC and back. Averaged 26.3 mpg. Both calculated and dash readout.

I did notice that once I crossed the 17K mile barrier, my economy went up significantly as I was averaging mid 23s on the highway and now it's more like low to mid 26s.

Now to my point...diesel vs. gas...you are going to spent about $4K more for the diesel plus the fact that currently (at least here in PA) diesel is $1.20-$1.30/gallon more than gasoline. With the highway fuel economy I am currently getting (plus I average in the low 19s bopping around) and the extra costs associated with the diesel in 1) just getting it and B) the cost of fuel, in my mind just the 3.6L gasser is more than adequate. I do read occasionally that those who are lifted and have the jymungus tires will see the fuel economy advantage with the diesel so there's that but you're still going to pay another $20 or so per fill up than those of us with gassers.

Just my $0.02 ($0.03 Canadian).

Good point except if your going to lift and big wheels and tires no regear there 4k and the power is night and day difference glad to here your getting 19 in a gasser I've owned 5 new 3.6 gassers never got over 17 stock driving like a little old lady.so the extra 10++ mpg pays off for me

Sponsored