Re-gear opinions 2020 JL Wrangler Pentastar 6spd manual

Toycrusher

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The torque line isn't what matters, it's the HP curve and it goes up all the way to redline. Despite your obvious belief, horsepower provides the acceleration and speed holding, not torque.

A conversation about what I can and can't afford isn't relevant, and would have an unfavorable outcome for you. I will say my M5 and my wife's Range Rover have similar RPM in their top gear and also run stock gearsets. And even though they both are far more powerful than my JL, they downshift to accelerate at highway speeds.
Yup, that's why the horsepower rating exists. A turbo 4-banger making 400 hp is capable of moving a load just as well as a 400 hp Diesel in a Superduty, if you geared the thing low enough to accelerate up to speed. However, it's not the right application, as going cross-country at 8000 rpm is probably not a recipe for reliability. Both engines are just as powerful, they just have different operating characteristics.

Torque may be relatively flat on the 3.6 from 2000-6500 rpm, but try timing the rate of acceleration. See how long it takes to run from 2000 to 3000 rpm, 3000-4000, and 5500-6500 rpm. You will find that the horsepower the engine is making at high rpm cuts the rate of acceleration significantly. 2nd gear is probably 1-1.5 seconds from 2000 to 3000 rpm but 5500-6500 is less than half a second.

That's the beauty of selectable gears, the gear you choose for a give mph determines the horsepower at your disposal





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Oletimer

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The torque line isn't what matters, it's the HP curve and it goes up all the way to redline. Despite your obvious belief, horsepower provides the acceleration and speed holding, not torque.

A conversation about what I can and can't afford isn't relevant, and would have an unfavorable outcome for you. I will say my M5 and my wife's Range Rover have similar RPM in their top gear and also run stock gearsets. And even though they both are far more powerful than my JL, they downshift to accelerate at highway speeds.
I wasnt speaking to you directly about not being able to afford it, if it was typed that way, my apology.
And i understand your thoughts on horsepower. But I've done gear swaps on over 20 4x4s , all lifted.
In real life it makes a world of difference. And there are many on this forum with more money than both of us. Lets don't embarrass ourselves.
 

Oletimer

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Yup, that's why the horsepower rating exists. A turbo 4-banger making 400 hp is capable of moving a load just as well as a 400 hp Diesel in a Superduty, if you geared the thing low enough to accelerate up to speed. However, it's not the right application, as going cross-country at 8000 rpm is probably not a recipe for reliability. Both engines are just as powerful, they just have different operating characteristics.

Torque may be relatively flat on the 3.6 from 2000-6500 rpm, but try timing the rate of acceleration. See how long it takes to run from 2000 to 3000 rpm, 3000-4000, and 5500-6500 rpm. You will find that the horsepower the engine is making at high rpm cuts the rate of acceleration significantly. 2nd gear is probably 1-1.5 seconds from 2000 to 3000 rpm but 5500-6500 is less than half a second.

That's the beauty of selectable gears, the gear you choose for a give mph determines the horsepower at your disposal
Not exactly i have peterbuilts that have 2000 pds of torque and only 550 horsepower. Its the torque that enables them to run down the road loaded at mph turning 1800 rpm.
And i order them with lower gears to give them better acceleration.
Torque matters, just like the old cj in my profile, it never lacked for power. It had great low end torque.
 

Toycrusher

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Not exactly i have peterbuilts that have 2000 pds of torque and only 550 horsepower. Its the torque that enables them to run down the road loaded at mph turning 1800 rpm.
And i order them with lower gears to give them better acceleration.
Torque matters, just like the old cj in my profile, it never lacked for power. It had great low end torque.
Torque characteristics of an engine have everything to do with the application. Your Peterbuilt only needs 1800 rpm to make 550 hp, which is ideal for practical gearing and longevity. However, a 550hp pro-stock motorcycle V-Twin could also move that load, if the truck was geared for 15,000 rpm at highway speed instead of 1800 rpm. It's a dumb comparison, and the V-Twin wouldn't last 10 min, but it simply illustrates the fact that horsepower is the method used to compare the work-capability of engines that may have very different characteristics.

And again, your Peterbuilt, even with 2000 lb/ft of torque, would be a dog if you always short shifted at 800 rpm instead of running it up through the full rpm range available to you.
 

Boutch76

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Gearing needs to fall in an appropriate range for drive-ability. The 3.45 ratio on non-Rubicon models was an insult. Stock should have been 3.73 or 4.10 for all Wranglers. However, when you struggled going uphill, you were in Hi-range? In my Rubi, 4-Lo and 1st is geared so low I can climb a wall at Idle straight up until I roll over backwards
I went offroading once with 4 people in the jeep and it stalled going uphill. In 4-lo. The service road I was on had several washed out section and this once place where you had a crevave 3 feet deep by 5 feet in length followed by a very incline hill. I had to rev it in 1st with the pedal brake on and then release. Or I could have asked everyone to get out.
 

Toycrusher

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I went offroading once with 4 people in the jeep and it stalled going uphill. In 4-lo. The service road I was on had several washed out section and this once place where you had a crevave 3 feet deep by 5 feet in length followed by a very incline hill. I had to rev it in 1st with the pedal brake on and then release. Or I could have asked everyone to get out.
I suppose with the 3.45 gears and 2.73 T-case it was asking a bit of the Jeep. The Rubicon with the 4:1 T-case is far more forgiving.

However, a tip for you in those situations, if you need to start on an incline, and you only have two feet for three pedals... try using your handbrake. I'll lock up the handbrake just enough to hold my truck (when pulling boats up and out of steep boat ramps) or Jeep in position. I'll shift into first, give a little gas and load up the clutch, then release the handbrake. You look like a smooth pro, few will realize how you do it.
 

ToxicBanana

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For me in the Rubicon Manual. <1000feet above sea level
Stock 33" 4.1 was fine with 6th on flat or light hills.
Now 35" 4.1 is a dog in 5th and 6th, 6th is unusable, 5th is just barely as usable as 6th stock. 4.88 or 5.13 seem the next step for me.
 

Rockywoolf

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With a 6 speed manual on 37s with 5.13 gears at 70 mph I am using 2500 rpms in 6th gear. 5.13s are my preferred gearing on the 6 cyl engine
 

ChattVol

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5.13 installed on my JLUR rolling 37s on my manual 3.6. Perfect gearing. Just need to adjust cpu. Only way to go. I also replaced front axle shafts eliminating s
@Rockywoolf @Oletimer @rustyshakelford @intentsrig. I'm getting closer to pulling the trigger on 5.13 or 4.88 for my 6 speed with 37s/beadlocks. I appreciate your feedback that 5.13s are great offroad, driving around town and cruising 2 lane roads at 55mph in 6th gear getting 17mpg. Will you provide feedback on how they perform on the hwy cruising at 75mph at 2600 ish rpm? It seems peak efficiency with 5.13s is around 55mph...how much do your mpg's drop cruising at 75mph? Thanks for your help.
 
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ChattVol

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I think he said he wants to get back his mpg is that possible with that?
I'm no gearing expert... but it's pretty clear looking at the calculators that 4.88s with 33s aren't going to be efficient if he drives on the highway. Seems like a bad fit considering the OP's stated needs...4.56 is plenty.
 
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Melny67

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No...4.88s with 33s aren't going to be efficient if he drives on the highway. Bad fit considering the OP's stated needs...4.56 is plenty.
How about with the auto transmission? Is the stock 3.45 ratio with 33 good on highway with light offroading.
 

ChattVol

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How about with the auto transmission? Is the stock 3.45 ratio with 33 good on highway with light offroading.
Alot of it is personal preference and depends on the terrain. I've only ran 3.45 and 4.10 gears with the 6 speed. I'd take it offroad a few times as it is and then reevaluate.
 

Oletimer

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I think he said he wants to get back his mpg is that possible with that?
It's all perspective, I was around 16.5 mpg at 35 psi. Then 16.1 at 28 psi. Now I'm at 15.4 at 22 psi
I spend several hours a day off road. I'm happy. Best fuel mileage of anything I've ever owned .
It's got 10,000 miles in 4 months, but if I only drove it weekends I would have 5.38s.
Just my perspective.
 

Oletimer

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@Rockywoolf @Oletimer @rustyshakelford @intentsrig. I'm getting closer to pulling the trigger on 5.13 or 4.88 for my 6 speed with 37s/beadlocks. I appreciate your feedback that 5.13s are great offroad, driving around town and cruising 2 lane roads at 55mph in 6th gear getting 17mpg. Will you provide feedback on how they perform on the hwy cruising at 75mph at 2600 ish rpm? It seems peak efficiency with 5.13s is around 55mph...how much do your mpg's drop cruising at 75mph? Thanks for your help.
4.88s with 35s .. It will go up tall bridges , climb most hills in North Carolina interstate travel without downshift. I can run 50 in Florida traffic in high gear.
I just still wish for a lower reverse.
I don't ever run over 65 mph , mileage drops quite a lot over 70.
I'm at 2600 at 70 mph
 

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