MPG and range

[Trippin01]

So I just did a trip from Boise to Tahoe (yes I did a little bit of the Rubicon Trail since I was there) anyway, I got to play with different speeds and MPG. At 80 mph (the posted speed limit in Nevada) I got 10 mpg, but at 65 I got 18 mpg.
Jeep year & trim: 2020 Sport S,
Mileage: 6k
Engine: 3.6 pentastar
Fuel type: 87 octane
Lift: Rough Country 2.5" lift
Tire size and model: 285 75R 17 (34's)
Diff gearing: 4.10
Tuned?:
Other add-ons: Ragtop , so a slight bit taller
Tire PSI: (36)
Speedometer re-calibrated? Not Yet
EVIC or hand calculated?:
Local driving conditions: Fairly flat, not sure of wind direction but I would guess 5-10 mph varying direction.
Average MPG: 16.4

That said, earlier this summer in Yellowstone park I was getting 28mpg @ 45mph no lift and stock tires.

Sponsored

 

[ShadowsPapa]

So I just did a trip from Boise to Tahoe (yes I did a little bit of the Rubicon Trail since I was there) anyway, I got to play with different speeds and MPG. At 80 mph (the posted speed limit in Nevada) I got 10 mpg, but at 65 I got 18 mpg.
Jeep year & trim: 2020 Sport S,
Mileage: 6k
Engine: 3.6 pentastar
Fuel type: 87 octane
Lift: Rough Country 2.5" lift
Tire size and model: 285 75R 17 (34's)
Diff gearing: 4.10
Tuned?:
Other add-ons: Ragtop , so a slight bit taller
Tire PSI: (36)
Speedometer re-calibrated? Not Yet
EVIC or hand calculated?:
Local driving conditions: Fairly flat, not sure of wind direction but I would guess 5-10 mph varying direction.
Average MPG: 16.4

That said, earlier this summer in Yellowstone park I was getting 28mpg @ 45mph no lift and stock tires.

Wind resistance rises exponentially over about 60 mph. So it only figures if you drive over 60-64 gas mileage goes down the toilet. To me that's a duh (life-long mechanic - seen a lot)

My own MPG AVERAGE hit 20 today after about 200 miles driving over the course of the past week - errands, some highway, some town, mostly rural roads at about 45-50 mph.
I was doing an easy 19+ until today.
TOTALLY stock Overland, stock tires, wheels, automatic transmission, 87 octane 10% - the normal in Iowa.

Jeep year & trim: 2020 Overland hard top
Mileage: 200
Engine: 3.6 pentastar
Fuel type: 87 octane 10%
Lift: none-stock
Tire size and model: stock
Diff gearing: 3.76/stock
Tuned?:
Other add-ons: none
Tire PSI: 39 - as it came to me
Driving 1/3 highway/interstate, 1/3 rural highways 1/3 in town

 

[WXman]

Wind resistance rises exponentially over about 60 mph. So it only figures if you drive over 60-64 gas mileage goes down the toilet. To me that's a duh (life-long mechanic - seen a lot)

This is 100% true. But, one thing I'll add that I have noticed about this truck specifically is that if I set the cruise at, say, 55 MPH the transmission will cycle between 7th and 8th more often. So, I actually see better MPGs closer to 65 where the trans. stays in 8th due to the extra RPMs.

 

[ShadowsPapa]

Yes, That's av variable for sure and would vary with gearing and tire size --but all things being equal, the wind thing....

 

[danielspivey]

What PSI is everyone running?

I noticed my MPG really dropped when I decreased my pressure from the stock (41 or whatever) to around 34/35. I decreased pressure to improve steering (which it did greatly) but dropped the MPG by about 2.5 mpg.

This was about the same drop with stock and wildpeak (285/75r17) tires.

I guess the more the tire is filled the better it rolls?

 

[PyrPatriot]

This is 100% true. But, one thing I'll add that I have noticed about this truck specifically is that if I set the cruise at, say, 55 MPH the transmission will cycle between 7th and 8th more often. So, I actually see better MPGs closer to 65 where the trans. stays in 8th due to the extra RPMs.

That is true. I see the best MPGs at 75mph. Engine runs the smoothest and feels like it has the most power. However, mine says it is in 8th gear anywhere above 45mph and not going uphill.

 

[Gecko-JKU]

Still waiting on my Gladiator here, but one thing I haven't seen anyone post on is what altitude they live at. Here in Colorado Springs we are generally over 6500 feet. Horsepower loss is noticeable. I believe MPG ratings are generally done at 55 degrees at sea level so it would be interesting to see if people struggling with gas mileage are at higher altitudes.

 

[PyrPatriot]

Still waiting on my Gladiator here, but one thing I haven't seen anyone post on is what altitude they live at. Here in Colorado Springs we are generally over 6500 feet. Horsepower loss is noticeable. I believe MPG ratings are generally done at 55 degrees at sea level so it would be interesting to see if people struggling with gas mileage are at higher altitudes.

That is a good point. And you can't tell by user location most times. For instance, I live in KY, which ranges from flat/basin type lands to mountains

 

[Trippin01]

while I routinely go to elevations of 8,000', It's usually in a windy (wine-dee) mountain highway setting, most of the time pulling my 4.000 lbs travel trailer. I don't know of very many highways/interstates that have any extended 6500' - 8,000' elevated plateaus to get an accurate mpg rating near me. I know that when I do pull my trailer on steep mtn passes above 6500' I don't notice any substantial power losses, or temperature fluctuations on any of the gauges. I routinely pulled my trailer up to 8,000', on SxS trails, in 4-Low with no significant or noticeable power loss or anything close to overheating. In Idaho, on these types of roads, and under this type of work duty, MPG's would be almost impossible to accurately record, and are pretty much irrelevant in this setting and type of usage. I think it does what I need it to do, and it does it easily and reliably. I'm not concerned about MPG's under these circumstances, but thats just me.

 

[ShadowsPapa]

HP and MPG will be lower on a naturally aspirated engine at higher altitudes. Less air going in, the system will lean out the injection to compensate, lowering the BTU output of each charge.
Cooler air is denser and means it's packing more air into the chamber and can handle more fuel being injected keeping the A/F ratio close to optimal.
It's like in drag racing - you want cooler denser air getting in - it can shave tenths of seconds at least off your times.
A friend of mine ran a dual snorkel air cleaner housing with hoses up to funnel shaped scoops he put in place of the center two headlights of his 4 headlight Ambassador race car. Made a difference making only that single change.
Humid cool air even better, the humidity provides oxygen. Burns better and cleaner. Both of my 4.0 equipped vehicles wake up nicely on a 45-50 degree humid spring or fall day here.

 

[hjdca]

How the HELL are you guys getting such great mileage ?
I have an LE with 35s and THE ABSOLUTE BEST I have gotten so far in mostly city driving is 13.6!!
What the hell is wrong with my truck? I am feathering the throttle and have almost never gone WOT.

13.6 is pathetic. Supposedly the dealer did a "Mopar Calibration" when they installed the new wheels and tires but man, I'm getting murdered over here.

I do almost all City driving with about 10 miles of highway driving in between. And it's mostly in traffic. But I would expect 15-17 for that. Not 13.5.

Is it possible the calibration is not done correctly? How can I make sure?

I would say that all those Gladiators getting great mileage live in flat states. I noticed you live in California like me. Most of my drive is spent climbing up and down mountains to get into the various valleys in California. I have never been able to duplicate sticker mpg in any car I have ever owned.

 

[ShadowsPapa]

When you change tires you change the load on the engine for a given speed and thus the gear ratio. You can't modify a vehicle with bigger and/or fatter tires and expect stock fuel economy. And anyone who calls Iowa "flat" has never driven southern or SE Iowa LOL. Even the OTR drivers struggle at times and the coal trains used to have trouble taking off. In 1976 that "freedom train" or whatever it was called had to call in an extra engine for parts of this state. It not be mountains by any stretch but the grades are tough if you are loaded down. Ask some of the drivers about the area between about Newton and Iowa City or so along I 80.
Northern Iowa is so flat that even field tile doesn't always help drain fields - water simply doesn't run, it sits.
Anyway - check their elevation and if they are running STOCK tires. Again, you can't change the gear ratio or the rolling resistance with tire changes and expect high teens or lower 20s.
I am still hovering at 20+ with a bit over 200 miles on it - and it's not even loosened up yet. BONE STOCK Overland - they are made for MPG.

 

[BuckSawLilandtheGoose]

Jeep year & trim: Rubicon 2020
Mileage: 3543
Engine: 3.6 pentastar
Fuel type: 87 octane
Lift: 2.5 in Rubicon Express
Tire size and model: 35x12.5R17 Hankook Dynapro MT
Diff gearing: 4.10
Tuned?: no
Other add-ons: S&B cold air intake
Tire PSI: (32)
Speedometer recalibrated? no
EVIC or hand calculated?:
Local driving conditions: Flat, sea level, city
Average MPG: 12.2

 

[MarineHawk]

… mine says it is in 8th gear anywhere above 45mph and not going uphill.

I read a lot people saying that they know which gear they're in at any given time when in Drive with the auto trans. How do you know? Where is it in the display? I haven't discovered that yet.

Many thanks in advance for any answers.

 

[PyrPatriot]

I read a lot people saying that they know which gear they're in at any given time when in Drive with the auto trans. How do you know? Where is it in the display? I haven't discovered that yet.

Many thanks in advance for any answers.

Well true Jeep owners just KNOW what gear they are in by feel, as we are one with our vehicles.

Just kidding

In the display settings (the one in front of the steering wheel), when you go into setup/settings scroll through those until you reach the Gear section, there is an option to check Individual Gears. The menu is the one that says you can't enter it while the vehicle is in motion.

Sponsored