The worst engine choice. The 392.

[JeepViking13]

If it's set up right, a lifted JL doesn't feel at all sketchy on the freeway at 85mph+ or in the desert at 100+. Or 2019 drove 5200 miles on a cross country roadtrip in May, with 3.5" of lift, 38's, and 5.38 gears with the cruise set between 80 and 90. The only issue we had was even the 2.0t gets real thirsty at those speeds. I'd even bet the 392 doesn't get any worse mileage at that point. If you're just wheeling at an off road park, odds are you might put in 100 miles in a weekend, no the 392 isn't that thirsty. The Rubicon trail is 18 miles, you could run it off the 392 for 1 mpg, and most report more like 12-15. The range isn't an issue. I used to wheel a wagoneer on 37's, that averaged 7-9 mpg. Even then gas was rarely an issue. There just aren't many trails that you need 100 miles of range let alone the 200+ that the 392 still achieves. Guys in stock geared saharas and sports get about the same mileage when they go to 35's. Range is rarely an issue. The 4 gallon difference in a JL means a lifted 392 likely has more range than a lifted JL regardless of engine choice.

Gearing is definitely important when it comes to the 2.0T and other similar engines. Right now my new Xtreme Recon with the 35s and 4.56 gears is averaging 20.8 mpg and it's not even broke in yet. That's driving local with no highway miles and up and down mountains. Just to get back and forth to my house is up and down a steep mountain. That's pretty decent gas mileage for a heavy Jeep on 35s and not fully broke in. So far impressed with the 2.0Ts power and efficiency.

For comparison I had a Challenger Scat Pack with the same 6.4 Hemi as the Wrangler. The Scat Pack was lighter with smaller tires and I averaged 14.6 mpg driving up and down my mountain and around town. I would imagine the 392 Jeep would get worse at my house. Or best case scenario the same. Also can't forget the extra heavy weight of the 392 on the front end. As far as range goes I felt like I was filling up my Scat Pack all the time.

Sponsored

 

[Brew211]

Sure an almost 500hp v8 isn’t going to help much off-roading going over technical obstacles,

Over 450 pound-feet of torque with 4.56 gearing would definitely help rock crawling over technical obstacles.

 

[Willing&Able]

Curious what the delta in gas mileage is for the 392 vs the 3.6 on the highway under heavier loads? I have the 3.6 w 37", 4.88, 6MT, and extra weight (winch, armor, lighting, etc.) and I would dip to < 10 mpg on the highway going up slight inclines w a 400# trailer in tow (two kayaks). Guessing the 392 w AT would strain far less and get better mpg....

 

[Brew211]

Curious what the delta in gas mileage is for the 392 vs the 3.6 on the highway under heavier loads? I have the 3.6 w 37", 4.88, 6MT, and extra weight (winch, armor, lighting, etc.) and I would dip to < 10 mpg on the highway going up slight inclines w a 400# trailer in tow (two kayaks). Guessing the 392 w AT would strain far less and get better mpg....

Same setup 6MT, 37’s, bumpers, skids, with 5.13 gearing, average 13 mpg no matter how I drive.

 

[70sKid]

The 392 is by far the worst engine to choose to be in your Wrangler.

Think about it. What’s a rubicon built for? Off-road.

You don’t go fast off-road except maybe in dunes, but, even then you don’t ever go over 99 mph…

You can’t stay at an off-road park for the whole weekend without worrying about refueling halfway through your second day.

If you’re actually overlanding you’re going to have to worry about fuel much more than the weekend warrior offroader.

You have to use 91 or above fuel to power this monster.

Besides Jeep limiting your options for interior color, small exterior color palette choices, and required options on the 392. The con that makes this the worst choice to wheel on the weekend, overland for the week, and even daily drive (especially in today’s fuel price state) is the fuel mileage. The 392 has a drinking problem.

Also I know some like to go fast. However, when you lift a Jeep and throw 37-40in tires on it, 1, you’re going to be slower and 2 it feels a lot more sketchy to be going 80mph in any wrangler with that build regardless of engine!

I’m sure there is some extravagant reason that the 392 is the best wrangler to buy for some crazy build with endless fuel cans and being pulled on a trailer or something, but, most people won’t do that.

So basically what I’m saying is the 392 really limits your your range too much.

With all that said. I still love the 392 just for the soul reason that it’s so cool.

Our 392 Has been a total blast that has exceeded all expectations. The single biggest complaint I can think of is the fact that it won’t be replaceable after 2023/24. This is one of those moment in time opportunities that you either execute on or just think about.

 

[Bzinsky]

Over 450 pound-feet of torque with 4.56 gearing would definitely help rock crawling over technical obstacles.

What hell you need 450ft lbs with 4.56 gears.

Total torque multiplication between trans, rear end, and lo range, is enough that could probably crawl over that obstacle with a 20hp briggs and stratton for a motor

 

[Zandcwhite]

Gearing is definitely important when it comes to the 2.0T and other similar engines. Right now my new Xtreme Recon with the 35s and 4.56 gears is averaging 20.8 mpg and it's not even broke in yet. That's driving local with no highway miles and up and down mountains. Just to get back and forth to my house is up and down a steep mountain. That's pretty decent gas mileage for a heavy Jeep on 35s and not fully broke in. So far impressed with the 2.0Ts power and efficiency.

For comparison I had a Challenger Scat Pack with the same 6.4 Hemi as the Wrangler. The Scat Pack was lighter with smaller tires and I averaged 14.6 mpg driving up and down my mountain and around town. I would imagine the 392 Jeep would get worse at my house. Or best case scenario the same. Also can't forget the extra heavy weight of the 392 on the front end. As far as range goes I felt like I was filling up my Scat Pack all the time.

Stock for stock, especially under light to moderate loads, of course the 2.0t is going to get significantly better mileage. Add extra drag, extra weight, and start pushing it western freeway speeds and you are pushing 20+psi of boost for hours cruising along the freeway. At that point you get 11-13 mpg and that didn't really change at all with the regear. 4.10's or 5.38's just changed which gear the trans was in, load is load. Conversely the 5.7 in my ram, which happens to weigh only 100lbs more than our JLUR, returns 13-15 mpg in the same conditions. I don't own a 392 JL, but I'm willing to bet a similarly built one will get similar mileage on the freeway and rock crawling, as once you get into heavy loads it takes fuel to do the work. Stock we got 17-19mpg, but that was 800lbs lighter, less rolling resistance, 6.5" lower, and far less drag. Wheeling built Jeeps all over the country is going to result in poor fuel mileage period. Even the ecodiesel guys I know with similar builds are lucky to average 15mpg with similar driving styles and speeds. The difference is they can get mid to high 20's on country highways at lower speeds, I can get 17 in those conditions, and the 392 will likely still be around 14. In that scenario obviously the ranges are wildly different, but gas stations are everywhere.

 

[Willing&Able]

Same setup 6MT, 37’s, bumpers, skids, with 5.13 gearing, average 13 mpg no matter how I drive.

I'd love to pick your brain. On highways, I assume you don't use 6th gear? When I'm in the ~75 mph range I cruise in 5th gear (6th useless), if I hit the slightest grade incline of the road I will bleed speed - rapidly if I'm in a hilly area. I'll often have to drop to 4th and with the gas pedal to the floor will increase speed by 1 mph every few seconds. I have no passing power in 5th and have to drop to 4th as well.

At that speed 4th is over 3k RPM's and with my AWE trail exhaust the noise almost makes it difficult to talk. Considering replacing that, but may just go AT in a 392....

I'm on 4.88's so not as short of gears, but wouldn't think that is the culprit. I also have a family of 5 with three small teenagers in the back.

 

[JSFoster75]

I think someone in a high position recently said, "If you can't afford gas, buy a Tesla"... Of course, they are so out of touch with reality that they didn't stop to think that you can buy a LOT of gas for the cost of a Tesla payment... I just drove 2,300 +/- miles in my JLUR 2.0 at 17mpg (loaded down with people & luggage) and only spent $630 in fuel. While that sounds like a lot, that's about double what most Americans drive in a month, and most cars get a lot better than 17mpg...

If you can afford the gas, buy whatever car you want...and enjoy it.

 

[GladiSD]

I have 37s on my 392 and couldn’t care less about mileage. If you don’t have a commute and it’s your toy, the thought doesn’t even cross your mind. I have four cars and they all get s*%t mileage. I tend to think that most 392 owners don’t give consideration to mileage when buying these things, they DO give consideration to (s)mileage.

 

[Old Jeeper]

I have seen just about every engine you can stuff under the hood of a Jeep from 426 Hemi all out to a Cummins diesel.

That said: YOUR Jeep, YOUR wallet, YOUR way.

A lot is the ? of what are you going to do with it?

IMO if you are a SERIOUS Rock guy, the engine of choice is the fabled I 6 of the TJ. That is the best combo for the rocks.

Its not the engine, its the gears...ever had dinner it a rotating restaurant atop a tower in Seattle or Dallas or any of the others. The motor that spins that restaurant is ¾ hp.

 

[X99104]

Curious what the delta in gas mileage is for the 392 vs the 3.6 on the highway under heavier loads? I have the 3.6 w 37", 4.88, 6MT, and extra weight (winch, armor, lighting, etc.) and I would dip to < 10 mpg on the highway going up slight inclines w a 400# trailer in tow (two kayaks). Guessing the 392 w AT would strain far less and get better mpg....

19 Rubi with 3.6 MT 4.10 gears, 2.5 " lift running 37" Nittos, Warn Elite front and rear bumpers with M8000, about 500 lbs of work related tools/gear = 17 mpg for 50k miles

22 392XR auto 4.56 gears with same winch on steel bumper package with the same work stuff = 16 mpg for 11k miles

I run a lot of Highway miles between 70 and 79, I can't give a good opinion for off-road since work is keeping me busy. @Roki , I will be in your neck of the woods next month, hint, hint.

Other than the cost of running premium I would say they cost me about the same to run. Difference is that I have had to learn not to put the pedal all the way to the floor cause the 392 will launch itself and make the fuel economy reading drop to 1. I can't beat the sound of the 392 with open exhaust going down the highway

 

[Willing&Able]

19 Rubi with 3.6 MT 4.10 gears, 2.5 " lift running 37" Nittos, Warn Elite front and rear bumpers with M8000, about 500 lbs of work related tools/gear = 17 mpg for 50k miles

22 392XR auto 4.56 gears with same winch on steel bumper package with the same work stuff = 16 mpg for 11k miles

I run a lot of Highway miles between 70 and 79, I can't give a good opinion for off-road since work is keeping me busy. @Roki , I will be in your neck of the woods next month, hint, hint.

Other than the cost of running premium I would say they cost me about the same to run. Difference is that I have had to learn not to put the pedal all the way to the floor cause the 392 will launch itself and make the fuel economy reading drop to 1. I can't beat the sound of the 392 with open exhaust going down the highway

Very similar setup on my 19 JLUR as yours but I can't get close to 17 mpg. Usually see around 13 and if I'm on the highway going up inclines it drops to 8. I'm running 4.88. I almost feel like there is more frictional drag in my setup that saps power - could it be RCV axles or Adam's HD driveshafts????

 

[X99104]

Very similar setup on my 19 JLUR as yours but I can't get close to 17 mpg. Usually see around 13 and if I'm on the highway going up inclines it drops to 8. I'm running 4.88. I almost feel like there is more frictional drag in my setup that saps power - could it be RCV axles or Adam's HD driveshafts????

I did keep the R's above 2500 since that is where it pulled hills best. Seemed counter intuitive but found it worked well. Also I used the full ramp to come up to speed on the hiway cause if you push it it will empty the tank. I barely saw 5th and 6th gear with the 4.10 so I expect you would rarely see 6th with the 4.88. Try it for a tank and see if things improve.

The 392 has RCV type axles so I wouldn't think you have any excess drag there.

Best of luck,
Andy

 

[Ten4Jeep]

The 392 is by far the worst engine to choose to be in your Wrangler.

Think about it. What’s a rubicon built for? Off-road.

You don’t go fast off-road except maybe in dunes, but, even then you don’t ever go over 99 mph…

You can’t stay at an off-road park for the whole weekend without worrying about refueling halfway through your second day.

If you’re actually overlanding you’re going to have to worry about fuel much more than the weekend warrior offroader.

You have to use 91 or above fuel to power this monster.

Besides Jeep limiting your options for interior color, small exterior color palette choices, and required options on the 392. The con that makes this the worst choice to wheel on the weekend, overland for the week, and even daily drive (especially in today’s fuel price state) is the fuel mileage. The 392 has a drinking problem.

Also I know some like to go fast. However, when you lift a Jeep and throw 37-40in tires on it, 1, you’re going to be slower and 2 it feels a lot more sketchy to be going 80mph in any wrangler with that build regardless of engine!

I’m sure there is some extravagant reason that the 392 is the best wrangler to buy for some crazy build with endless fuel cans and being pulled on a trailer or something, but, most people won’t do that.

So basically what I’m saying is the 392 really limits your your range too much.

With all that said. I still love the 392 just for the soul reason that it’s so cool.

I disagree wholeheartedly! The 392 might be the worst engine choice for YOU, however it is the BEST and ONLY engine choice for us

My wife and I rode motorcycles all over the united states from 2000 to 2016. It was our hobby and preferred choice of vacation together. We did eventually grow tired of having severe weather patterns disrupt our vacations, so we sold the motorcycles and bought several sport cars for our getaways, including in this order; 2014 Camaro SS Manual 6-SPD, 2018 Camaro ZL1 10-SPD, and then a 2016 Z51 Corvette 7-SPD. The ZL1 was certainly the fastest but the corvette was by far the most fun with it's raw sounds and the way you felt connected to the road and also the environment around you. However, not too practical for some of the places we like to visit and also kind of awkward climbing in an out of.

The Jeep 392 provides the raw fun we are looking for and certainly does not insulate its passengers from the environment! It is also way more practical than a Vette and certainly easier to climb in an out of

We consider the Jeep 392 as more of a thrill seekers choice and provides an ultimate experience that absolutely cannot be found in ANY of the other Jeep Wrangler models.

Sponsored