392 gas mileage

[Punkindug]

Just drove my daughters stuff up to move in college today for senior year. Up thru the adirondack mountains in upstate NY. My previous JLUR w/ 3.6L averaged 18.1 on the sage exact trip. 1st trip with the 392 and got a whopping 20.9! How can that be??? Not even 1/4 of a tank 110 miles. WTF? Not near as much downshifting as the V6 so I figured the torque on the V8 helped? Up the mountains and down. Averaged 55mph, very humid for upstate NY today and 88 degrees. Running 91 octane non-ethanol. Rte 28 and 30 if anyone knows where that is.

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[SSWIM]

Amazing is all I can say. I have never came close. Easy drive, 55-65MPH nets me around 16-17 MPG.

Sam

 

[Monster1926]

MDS is nice fuel mileage wise but it also destroys cams.

 

[XJfanatic]

Thinking some of that probably comes from coasting down hill. My 2.0T gets 21 normally on flat ground with the heavy ridge grapplers. In the hills it is closer to 23 due to all the time just coasting.

 

[aldo98229]

See, honey? We need a big honking V8! It will save us money...!

 

[graytrucks]

The 392 is quite good on the highway, as are most V8s (when maintaining steady speeds). I get high teens/low 20s in most highway situations. I’ve always gotten better highway MPG with more powerful engines. Local driving or high speed acceleration to pass is a different story…

 

[supermike]

200 miles between fill up, wish we got a 35 gal tank.

 

[GATORB8]

I always thought it was weird, but I do a Charlotte - Knoxville run across the Blueridge/Smokies about once a month and always get better mileage in my Ram than I do on flat interstate. I think the V8 torque makes the climbs more efficient and then coasting down grade pulls the average up a lot.

 

[65Hemi]

Just drove my daughters stuff up to move in college today for senior year. Up thru the adirondack mountains in upstate NY. My previous JLUR w/ 3.6L averaged 18.1 on the sage exact trip. 1st trip with the 392 and got a whopping 20.9! How can that be??? Not even 1/4 of a tank 110 miles. WTF? Not near as much downshifting as the V6 so I figured the torque on the V8 helped? Up the mountains and down. Averaged 55mph, very humid for upstate NY today and 88 degrees. Running 91 octane non-ethanol. Rte 28 and 30 if anyone knows where that is.

Your odometer probably needs re-calibrating.

 

[Bzinsky]

The 392 is quite good on the highway, as are most V8s (when maintaining steady speeds). I get high teens/low 20s in most highway situations. I’ve always gotten better highway MPG with more powerful engines. Local driving or high speed acceleration to pass is a different story…

This so much.

I have a sierra with an L86 in my driveway. I get 10mpg in suburbia! But i set it on cruise control at 55mph with all the fluids warmed up, on flat ground, in the summer, I’m getting close to 30mpg.

It’s really not the steady state cruising that ruins v8 fuel mileage, it’s when you change the speed.

That’s why I could never own a 392 as I’m surrounded by 20 miles of stop signs and traffic lights. If I lived in a rural area where it’s all 50-65mph roads, it’s a non issue.

 

[RubiSc0tt]

Shoutout to OP with the 392 in Albany! I'm in Saratoga.
The extra hp/torque from the Hemi going through the ADK's probably helped. I have the v6/ manual trans/ 4.10, and we drove from Saratoga to Maine via I90/I495/I95 and man o man, coming through the Berkshires with a loaded down Jeep with the v6 and stock gearing was BRUTAL. I had to downshift to 3rd a few times just to keep up with traffic. It happened so many times my son (5) would ask "hey dad, what if you had the Jeep with the BIG ENGINE?!"
My wife loved that.

 

[TheBirdie72]

Is the title of this post an oxymoron?

 

[2nd 392]

Is the title of this post an oxymoron?

I get about 10.5 to 11.5 in town, off road plus dependent and avoiding MDS. Oh well- gas is cheaper than cam replacement, and enjoyment costing ~ 1 mpg is an acceptable trade off. So absolutely an oxymoron.

 

[JeepGeezer]

Will someone please tell me what MDS is?

 

[caraholic]

Curious do you have a non XR? I was trying to get good mileage on my last 600 mile highway trip and only managed 14.4. I do have an XR.

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