Rob 12B1P

If theyd of had a V8 jk available thats what I would have bought. I think most people would go that route. The problem is theyd have to completely redesign the Jeep to handle the weight and power.

Freewill

My JK and my F150 2WD SWB are almost exactly the same weight - 4600 pounds with a driver and hardtop/canopy.

The 5.4 F150 automatic can run pretty much any hill except the steepest mountain pass in 4th gear, and get about 18.5 MPG.

The 3.8 JK automatic will downshift if the Jeep even sees a hill in the distance, and get about 18.5 MPG.

I'd buy a V8 JK in a heartbeat. In fact I'm so sick of the constant downshifts that I may be a Hemi candidate.

goaterguy

Have you test driven a JK with the Pentastar?

GJeep

The 3.6L Pentastar JK has more power & less MPG than either the F150 or the 3.8 JK.

My impression is that there would be a much larger market niche for the Diesel JK than for the Hemi.
From the Chrysler point of view, the move to diesel already exists and didn't require major changes, while dropping in a Hemi means changes of the power train and suspension.

For me, the 3.6L is a good balance between slow offroading and city/highway. It does not lack power.
With the JKU and load, on wet asphalt or sandy trail, the wheels are easy to spin.
The lighter 2-door would spin the wheels even sooner.

I wouldn't burn more fuel for extra Hemi power that I don't need.
If I wanted Corvette performance, I'd have gotten a Corvette, and not a 4" lifted cube

lanslide

How does the Wrangler's Pentastar 3.6L compare in performance to the Diesel engine equipped ones? I know Diesels have more low end torque and get better mileage but...which one is more fun to drive "on road"? Which one accelerates faster?

My 12JK spins wheels if you hit it too hard as it is - I can't imagine more power in a stock 2 door JK.

GJeep

On roads, the Pentastar is more vivid.
On long, steep up slopes, the diesel would keep the speed better.

Here you can see the specs of all the models, and create a comparison table
(The diesel is at the end) --

2012 Jeep Wrangler JK 4x4 specifications, performance data

It includes an acceleration comparison chart.

0-100 km/h (62.5 mph) :
Pentastar 3.6L = 8.1 sec
Diesel = 9.9 sec

panthermark

I have no need for a V-8 Wrangler....it would not improve the tow capability....and would decrease fuel economy all at an added cost.

Freewill

But the 5.4 F150 and 3.8 JK weigh the same, have more or less the same lousy aerodynamics, and get the same mileage. I've always thought mileage was about weight and air flow more than engine size - unless you lead-foot the bigger engine. For me, a bigger engine turning lower RPM is always a good thing.

I agree the diesel would be great. Plenty of torque, low RPMs, good efficiency - but I could get the same thing from a gas V8. My driving habits would get me the same mileage, and I'd like the Jeep a lot better. In fact, I'd probably like the torquey old 4.0 inline six better than the minivan engine.

The 3.6 has more power, but its still a chipmunk engine pulling a draft-horse sized vehicle around. Maybe the 3.6 with an 8-speed gearbox would be a good combination. The close-ratio shifts would not be as annoying. (Also true of the 5-speed but 8 would be better.)

napamat87

Ford should build jeep, I've owned quite a few fords , some with the 300ci I6 and one with a v6 none of those trucks I ever had to do.anything to , except for routine maintenence. I went Chrysler because I wanted a jeep and the jeep has spent more time in the shop than on the highway.jeep needs to step up the quality!

GJeep

The slanted windshield, the much smoother sides and the bed behind, give the F150 a clear edge in air flow over the Jeep which has an almost flat and upright windshield, sticking-out fenders, and large & square cut-off at the back.

(Just see how much more bugs the Jeep windshield collects vs the F150.
That's air flow vs the lack of it.)

Another difference is that the Jeep engine has an extra load - it constantly rotates the front axle and driveshaft.
Therefore, if the Jeep has similar MPG - in spite of its lesser aerodynamics and the extra load - it's engine is more economic.
In other words - If you put the 5.4 V8 in a Jeep, MPG would be worse than the 3.6 Pentastar.

Also, at slow offroad speeds and more pressure on the pedal, the the 5.4 F150 would have gulped even more fuel.
The MPG of a diesel doesn't change much according to how much you press the pedal, while for a gas V8 it makes a big difference, so a diesel would be more economic for offroading.
I wouldn't call 285 bhp a "chipmunk engine"...