392 Hemi V8 Concept Reviews by Roadshow and Motor1

[OnlyOne]

Those of us that have owned a Power Wagon know exactly what kind of fuel mileage the wrangler 392 will get. I didn't care then, and won’t care sitting in the driver seat of the wrangler. If you’re worried about fuel mileage, you really shouldn’t own a gas engine wrangler..... buy the diesel or the electric.

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[word302]

My perspective isn't any better than anyone elses. I've just never had the expectation of any reasonable fuel economy out of a Jeep, especially one with a V8. And that's fine. That's not why you buy one. I'm not convinced the 392 Wrangler won't absolutely annihilate gas and that's one of many reasons why it'll never be anything other than a concept.

I never owned the Hemi JK, but it was a vehicle that accompanied us on a ton of wheeling and camping trips out in the boonies of Colorado. As I mentioned in a previous post, that thing had trouble getting above 12mpg on the highway unless you kept it under 65. It had ProRock 44s, but still ran the NSG370. We had a mutual friend who put a 6.1L in 2-door JK and it was pretty much the same story. Both Jeeps ran 35s.

My 3.6L JLUR is running 37s, but they're BFGs, so they're not really 37". They measure 35.5" and I get roughly 12mpg in the city and maybe 15-16mpg on the highway. The computer will tell me I average 18mpg, but that's fake news.

My 392 Challenger will do 20-22mpg on the highway, but averages 15-16mpg in the city. That's in street mode with MDS active. It gets a little worse in Sport mode. It's the same story with that computer, too. It'll claim I average 19mpg or so in the city, but that's also fake news.

So, combining all that together in a totally unscientific manner, I wouldn't be surprised if the 392 Wrangler dips as low as single digits in the city and fights to maintain 15mpg on the highway. I don't know what else they've done to the JL or the 392 itself. It's clearly not a simple transplant since they've reduced the power and torque, but that's more likely to not destroy other elements of the drivetrain.

I average 16 in my JLUR 3.6/manual with 3.5” lift and heavy 37s/beadlocks. Your previous posts said the Hemi would average single digits and that’s what I think is silly.

 

[rubileon]

I average 16 in my JLUR 3.6/manual with 3.5” lift and heavy 37s/beadlocks.

Mine's a stock 3.6+auto and it gets 16 in mixed driving. When do you get 16? What did you get when it was stock?

 

[Headbarcode]

I average 16 in my JLUR 3.6/manual with 3.5” lift and heavy 37s/beadlocks. Your previous posts said the Hemi would average single digits and that’s what I think is silly.

Yeah, same thought here. I'm on 3.5" lift and 38x13.50's, 50/50 city and highway, and my hand calculations toggle around 18-19 mpg.

Litebrites "Step Child" averages 15 mpg. It's got 40’s on bead locks, 5.5" lift, 6.4 srt hemi, zf 75 series trans, 60/80 axles, and weighs a hair under 7k lbs. And that's without everything they pack in the Jeep. Loaded up with gear, their probably at about 7400ish lbs and reportedly run at 75-80 when munching miles.

 

[word302]

Mine's a stock 3.6+auto and it gets 16 in mixed driving. When do you get 16? What did you get when it was stock?

I average 16. I averaged close to 19 when it was stock. The 4.10 gears with the manual help quite a bit in town. When I install the 5.13s I expect to improve slightly.

 

[TJJL19]

Anybody wonder what the tow rate will be on the 392?

 

[word302]

Anybody wonder what the tow rate will be on the 392?

The same as all the other motors. The limitation has never had anything to do with the power plant.

 

[Spank]

Your previous posts said the Hemi would average single digits and that’s what I think is silly.

I was speculating on a city average, not the combined average. And that's just based on the laughable gas mileage we got on the 5.7 in the JK back in the day. It never saw double digits in the city.

Mine's a stock 3.6+auto and it gets 16 in mixed driving. When do you get 16? What did you get when it was stock?

What's your elevation? That'll make somewhat of a difference, too. I live above 6,000ft., so naturally a vehicle that demands air and has no aerodynamics to speak of is going to hurt that much more.

 

[TJJL19]

The same as all the other motors. The limitation has never had anything to do with the power plant.

What is the limiting increasing , frame or axel? My 2020 AT4 3.0 Diesel has a 9,500 limit,while the big gas engine has a 12,500 limit because of the horse power incress.

 

[entropy]

Anybody wonder what the tow rate will be on the 392?

The towing on the wrangler is not limited by the engines. But now that you mention it, the V8 concept has a reinforced frame and a different suspension so it might be different. But they didn't change it with the diesel right? so I would think they would slap the same bs number on it.

 

[word302]

I was speculating on a city average, not the combined average. And that's just based on the laughable gas mileage we got on the 5.7 in the JK back in the day. It never saw double digits in the city.



What's your elevation? That'll make somewhat of a difference, too. I live above 6,000ft., so naturally a vehicle that demands air and has no aerodynamics to speak of is going to hurt that much more.

Like someone else posted, the lite brite guys are averaging 15 with their Hemi, 40s, and Dynatrac axles so I don’t really know what to tell ya man.

 

[word302]

What is the limiting increasing , frame or axel? My 2020 AT4 3.0 Diesel has a 9,500 limit,while the big gas engine has a 12,500 limit because of the horse power incress.

The short wheelbase and soft suspension is the limiting factor, of course your truck has a higher tow rating, it’s a truck.

 

[TJJL19]

The short wheelbase and soft suspension is the limiting factor, of course your truck has a higher tow rating, it’s a truck.

I know, I have a truck,what I was trying to show, was that the horsepower diffrence, made a towing diffrence, on the AT4

 

[ZeroTrev]

Well for towing at least, I he 2 door, 4 door, and gladiator all share the same engine and transmission don't they? I'd say weight is a pretty big toe factor too.

 

[Headbarcode]

Tow capacity is generated from how the frame and suspension is designed. For the wrangler, the frame was designed for flexing to a certain degree. This helps to absorb some of the pent up energy of the suspension at its extreme working limits. The suspension, as mentioned by word302, is too soft. Even the stiffer than stock aftermarket suspension kits are too soft for towing more than the 2k and 3.5k caps.

Towing requires a more rigid frame. The more so it gets, the higher the load/haul capacities get. That rigidity equals control over that added dead weight. Stiffer tow vehicle suspension also increases control, by limiting its own movements and reactions to the road. Unnecessary movement in the tow vehicle gets transferred to the trailer, which can snowball into an eye widening situation.