Best speed for MPGs

[OldGuyNewJeep]

I'll bet it's been discussed and that many factors play into this, but on flat road, at about what speed does the 3.6JL maximize its fuel economy--at least one from the factory?

Speaking of factors: I wonder if the benefits of 8th gear, for example, might be counterbalanced by ones of the Wrangler's less than aerodynamic shape.

Of course, the question's academic. Thanks.

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[jaldeborgh]

In town driving, yes this should be true.
Highway MPG should definitely be better in a manual though. The parasitic HP loss is wayyy lower in a manual. Seems like EPA just glosses over this, much like gearing differences. I guess they either don't test both transmission options, or gearing options?

If manuals offered better mileage every car model would offer one. The pressure to improve fuel economy to meet government standards would drive this behavior. It’s also the primary reason many automatic transmissions offer ECO, Sport and sometimes Race modes.

 

[2019RUBI]

I can't speak to the Wrangler just yet as it hasn't arrived but my old Tacoma would average around 30mpg at 45 mph with the cruise set. The current Camry DD gets about 48mpg at the same 45 mph.

Problme is this is on perfectly flat roads in the middle of no-where wisconsin with the cruise set. Any who wants to drive at 45mph

 

[roaniecowpony]

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[roaniecowpony]

The aerodynamic model the Jeep was designed from.

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[8flat]

If manuals offered better mileage every car model would offer one. The pressure to improve fuel economy to meet government standards would drive this behavior. It’s also the primary reason many automatic transmissions offer ECO, Sport and sometimes Race modes.

Manuals don't offer better mileage in city driving, which is where most people are using their cars.
I clearly said HIGHWAY mileage is better with manual. But even that isn't a large delta because the new autos are so good (more gears, lock up torque converters, etc)

 

[brazos]

I did a test run today.
A 13.5 mile, relatively flat highway run. No wind.
At 55, I got 27.2.
At 60, I got 23.8.
Turbo, 8 speed auto.

 

[roaniecowpony]

If mileage was the goal in a Jeep, you'd put skinny, minimalistic tread, tires on it and pump them up to about 80 psi, put a big rounded nose fairing on the front that nearly touches the ground, fender skirts, and a boat tail on it. It'd be hard to hit the trails in that rig. Buy a Prius if you want high MPGs.

 

[multicam]

The aerodynamic model the Jeep was designed from.

Haha! The barn actually has better aerodynamics than the Jeep. Look at the angle of the barn’s windshield... and the lack of a squared-off rear window on the barn would help air slipstream over it better than the Jeep. Plus the barn rides much, much closer to the ground.

 

[brazos]

I didn’t buy a Jeep FOR the gas mileage, but that doesn’t mean I don’t care about it.
I don’t get the “If you want good gas mileage, buy a Prius” line.
I don’t want a Prius. I want a Jeep.
And I want the best gas mileage I can get in my Jeep, without sacrificing performance.

 

[CalsJLUR]

It should be how many smiles you get per gallon!

But, to continue the theme of the thread. I find the my JLUR with the 3.6 and 8spd, get the best fuel milage between 55 and 60 mile per hour highway. But the difference between 60 and 65 is .5 miles per gallon and 70 and 75 is only 1.5 miles per gallon.

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