What Most Hurts MPGs: Weight, Diameter or Width

[TheBirdie72]

Maybe this could help you?

ok, I’m done now…

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[ohthatguy]

But an overweight fat guy on a bike is still gonna get worse mileage than a skinny in-shape one. I stand by my earlier point about donuts.

Ha, I wish it was a me thing but I’ve owned numerous 400+ HP cars and wasn’t skinny for any of them but those others were way better on MPGs (despite having the same or more powerful engines). Driver weight isn’t consequential to MPGs in this case. Besides, donuts are awesome.

 

[Industrialwrench]

Owning a Jeep and Caring about MPG IS what hurts the most. It’s not an economy vehicle, even the 4XE really isn’t. I haven’t cared about the amount of gas any of my vehicles takes since I could afford one with a functioning gas gauge. The 392 guys complaining really gets me laughing. Like, what did you think was going got happen? I honestly like seeing how bad of milage I can get in my SRT8 (around 8), and I am proud of wearing through a set of tires in under 6k miles. Shows I’m having fun. For those living on the edge financially with gasoline as a tipping point, buy a motorcycle as a daily and keep the jeep as a toy. Getting 70mpg and doing 3 second 0-60s is totally normal on a bike.

 

[ohthatguy]

Owning a Jeep and Caring about MPG IS what hurts the most. It’s not an economy vehicle, even the 4XE really isn’t. I haven’t cared about the amount of gas any of my vehicles takes since I could afford one with a functioning gas gauge. The 392 guys complaining really gets me laughing. Like, what did you think was going got happen? I honestly like seeing how bad of milage I can get in my SRT8 (around 8), and I am proud of wearing through a set of tires in under 6k miles. Shows I’m having fun. For those living on the edge financially with gasoline as a tipping point, buy a motorcycle as a daily and keep the jeep as a toy. Getting 70mpg and doing 3 second 0-60s is totally normal on a bike.

It’s not living on the edge, financially, thankfully. It’s more an issue of is the vehicle, delivering enough to justify the compromises and costs.

My last vehicle was an SUV with massively wide tires, a TwinTurbo V8 pumping out almost 600 hp in stock trim and it took down premium fuel at a rate of 16.5 miles per gallon. I never really thought about MPGs in that vehicle, because it was delivering so much for the compromises.

I think with the 392, I just have to slap the massive tires on, and enjoy the noise. It does sound better than anything else I’ve driven.

 

[Industrialwrench]

It’s not living on the edge, financially, thankfully. It’s more an issue of is the vehicle, delivering enough to justify the compromises and costs.

My last vehicle was an SUV with massively wide tires, a TwinTurbo V8 pumping out almost 600 hp in stock trim and it took down premium fuel at a rate of 16.5 miles per gallon. I never really thought about MPGs in that vehicle, because it was delivering so much for the compromises.

I think with the 392, I just have to slap the massive tires on, and enjoy the noise. It does sound better than anything else I’ve driven.

In that case I do believe Jeep did it wrong with the 392. Compared to other manufacturers top tier, the Off-road pinnacle “Rubicon 392” should have much more power with stronger axles/shafts and probably 37s from the factory. That and a higher top speed than a Geo Metro…Totally a personal opinion and a little biased because I’m a 2dr driver.

 

[ohthatguy]

In that case I do believe Jeep did it wrong with the 392. Compared to other manufacturers top tier, the Off-road pinnacle “Rubicon 392” should have much more power with stronger axles/shafts and probably 37s from the factory. That and a higher top speed than a Geo Metro…Totally a personal opinion and a little biased because I’m a 2dr driver.

Yeah, that 100ph limiter is like having a cane Corso on a short leash. But I think the speed ratings of a lot of capable tires is so low they worried about getting sued into oblivion if it could exceed the tires’ ratings.

When I use up or sell my experimental sets of tires, I will try 35x15.5 AT tires as it’s probably going to deliver the best performance and aesthetics for what I want the 392 to do.

 

[Industrialwrench]

Yeah, that 100ph limiter is like having a cane Corso on a short leash. But I think the speed ratings of a lot of capable tires is so low they worried about getting sued into oblivion if it could exceed the tires’ ratings.

When I use up or sell my experimental sets of tires, I will try 35x15.5 AT tires as it’s probably going to deliver the best performance and aesthetics for what I want the 392 to do.

You’ve got a solid point with the speed rating, I think the Jeep would look a bit strange with some low profile Z rated rubber.

 

[3TV]

Yeah, every vehicle I’ve owned offered a compromise of utility and fun weighed against its limitations and costs. I probably do glean less from this platform than most.

It isn’t because it’s not fun. This thing makes glorious noises. But there’s an old saying that comparison is the thief of joy. That likely applies in my case because I’ve been lucky enough to enjoy some pretty special vehicles.

Fuel economy has thankfully never been something I had to give much thought to over the years. The fact that it’s on my mind now probably is an indicator that the 392 is delivering too much compromise in various areas vs the enjoyment it delivers..

But given the percentage of the global population that wakes up to a dirt floor, I count myself lucky to have the opportunity to experience it.

Unfortunately, some people that buy a 392 go into the purchase thinking they are buying a performance vehicle. What you are getting with a 392 is a Jeep with a V8 engine. It is still a Jeep though, and still drives like a Jeep. If you are buying it for what a Jeep is built for (off road), and want the extra power and improved drivability from that extra power, then it is great. Best Jeep I've ever owned in fact. But as a "performance vehicle" it gets beat pretty badly.

I haven't owned a whole collection of performance vehicles, but I have owned a few. My latest is the Ram TRX that is parked next to my 392 in the garage right now. The TRX and the 392 were actually within $200 of each other in MSRP. But the TRX with its 700 HP supercharged engine, 14" of super plush suspension travel that is electronically tunable on the fly, and its luxurious quiet interior beats the 392 pretty much at everything. Everything but being a Jeep that is. There is no way I am going to take my TRX (or any other performance vehicle) where I take the 392.

Good luck with your 392. There are always other vehicles if it isn't working out for you.

 

[ohthatguy]

Unfortunately, some people that buy a 392 go into the purchase thinking they are buying a performance vehicle. What you are getting with a 392 is a Jeep with a V8 engine. It is still a Jeep though, and still drives like a Jeep. If you are buying it for what a Jeep is built for (off road), and want the extra power and improved drivability from that extra power, then it is great. Best Jeep I've ever owned in fact. But as a "performance vehicle" it gets beat pretty badly.

I haven't owned a whole collection of performance vehicles, but I have owned a few. My latest is the Ram TRX that is parked next to my 392 in the garage right now. The TRX and the 392 were actually within $200 of each other in MSRP. But the TRX with its 700 HP supercharged engine, 14" of super plush suspension travel that is electronically tunable on the fly, and its luxurious quiet interior beats the 392 pretty much at everything. Everything but being a Jeep that is. There is no way I am going to take my TRX (or any other performance vehicle) where I take the 392.

That’s a great combo to have in the garage and I agree with your take 100%. I need to recalibrate my expectations of the 392 and enjoy it for what it is.

 

[GMONEY]

I had a career in aviation. Whenever I see a vehicle (plane, car, truck, etc,) with high drag, I see big opportunity for reducing drag.

If you take a plane like the 787 Dreamliner, there is very little opportunity for aerodynamic improvements.

I owned an aerobatic biplane that had tremendous (coefficient of) drag in comparison. There were many easy things I did that greatly improved aerodynamics. I increased the top speed of that plane by double digits and reduced cruise fuel consumption significantly.

With a Jeep, it likewise has a lot of low hanging fruit. A lot more than a new modern sedan or sportscar. Also, with a vehicle that gets low fuel economy, driving the same miles per year, an X% gain in fuel economy equates to more $$ per year than for the high efficiency car.

In other words, higher drag vehicles have higher gains in $$ for drag reducing efforts.;

All fair points.

But OP did say he likes to hear the exhaust and as long as he's doing that all the time his mileage isn't going to get much better.

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