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Current Scrambler pics

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GreatCJ8 said:
Looking great! How does it do on the highway w 35s & 4.56?
Edited to add pics 🙂 I hope every Saturday is as fun as yesterday was. Played then worked in the 8
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It does great. Well as great as could be. At 50 it is not happy and low revs. It wants to go faster. Sweet spot is between 55 and 60. Over 60 it starts to rev higher than I want it to. Not to mention I don’t want to take it over 60 too often. To be honest, I try to stay off of the highways with it. And when I do, it is short distances.
 
gr8dain said:
It does great. Well as great as could be. At 50 it is not happy and low revs. It wants to go faster. Sweet spot is between 55 and 60. Over 60 it starts to rev higher than I want it to. Not to mention I don’t want to take it over 60 too often. To be honest, I try to stay off of the highways with it. And when I do, it is short distances.
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Wait, what? You are remembering that the 4.0 in and XJ/TJ/LJ WANTS to be at 2800-3000 RPM at speed, right? There's no damn way it's revving "too high" on you at 60. That's where all the power is and that's where they're set up to be on the highway stock.

I had to convince myself of this after the 4.0 swap because it felt different, but you should be able to roll at 75 all damn day long with that setup.
 
bigwalton said:
Wait, what? You are remembering that the 4.0 in and XJ/TJ/LJ WANTS to be at 2800-3000 RPM at speed, right? There's no damn way it's revving "too high" on you at 60. That's where all the power is and that's where they're set up to be on the highway stock.

I had to convince myself of this after the 4.0 swap because it felt different, but you should be able to roll at 75 all damn day long with that setup.
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You are probably right. I just have a fart can magnaflow 80 straight pipe muffler and it sounds super loud. I do jot have a working tach so I really have no clue what my RPMs are. So I need to get a real muffler on and get a tach. I am also a little wussy and fear I am over revving. When I probably am not.
 
gr8dain said:
You are probably right. I just have a fart can magnaflow 80 straight pipe muffler and it sounds super loud. I do jot have a working tach so I really have no clue what my RPMs are. So I need to get a real muffler on and get a tach. I am also a little wussy and fear I am over revving. When I probably am not.
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I will guarantee you are not.
 
gr8dain said:
You are probably right. I just have a fart can magnaflow 80 straight pipe muffler and it sounds super loud. I do jot have a working tach so I really have no clue what my RPMs are. So I need to get a real muffler on and get a tach. I am also a little wussy and fear I am over revving. When I probably am not.
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Has your speedometer been calibrated for the 35" tires and 4.56 gears?

Per Grimmjeeper.com

AW4
Transfer Case in High
4.56 gears
35" (34.7") M/T's

4.0.JPG
 
I run 33's and 4.10 with stock 4.0/AX15. I run 70-75 at 25/2700 RPM. This is where the 4.0 is happy. My stock 05 Rubicon with 31's and 4.10's loved 3,000 RPM at 78 mph. Sold it with 165k miles on it, never used oil, no engine problems at all.

The 258 will run above 2500 rpm on highway but it is nowhere near as happy. 258 torque curve much lower than 4.0.

You really want a 4.0 above 2500 rpm at 65+ MPH.
 
gr8dain said:
It does great. Well as great as could be. At 50 it is not happy and low revs. It wants to go faster. Sweet spot is between 55 and 60. Over 60 it starts to rev higher than I want it to. Not to mention I don’t want to take it over 60 too often. To be honest, I try to stay off of the highways with it. And when I do, it is short distances.
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Lol. I'm sorry. I have to have a little fun here.

So in reality most 35s actually measure 34. Your aw4 has an overdrive of .75 and redline for the 4.0L from what I remember is about 5,000 rpm. So that being said, you won't have to worry about over revving until you hit 150 mph. 👍 I think we can all agree here you will have other things to worry about other than over revving going that fast in a CJ. 😆

But seriously, as others have said... Let it rev! Those 4.0L engines like to sing! Even if your overdrive gear decided to kill itself and you were stuck in 3rd, you would only be at 3100 rpm at 70 mph. Some engines just love to sing. Last summer I used my Sequoia to tow my scrambler out to Colorado for Nationals. The entire way there it was roughly at 3700 rpm. Once I got to towing in the mountains it was damn near redline for very extended periods of time going up long steel grades. And it was happy. 😎
 
Yes. I changed the speedo gear in my 300. And I have validated using GPS that my speedo is accurate at many speeds.

And wow. Per that chart, I really am not revving at all. I really need to get a tach. If for no reason other than peace of mind.


FLCJ8 said:
Has your speedometer been calibrated for the 35" tires and 4.56 gears?

Per Grimmjeeper.com

AW4
Transfer Case in High
4.56 gears
35" (34.7") M/T's

View attachment 108953
Click to expand...
 
Mine is very happy around 72 on straight aways with plenty of skinny pedal left.. Tracks nice, doesn't wander but needs to be aligned still. I can see, though, how squirrely it can get, fast, if you get behind on "steering prediction" 😅 with a Detroit in the rear 😅. It's not happy yet going up the local mtns. But I believe there's still more tuning and learning to go with the Holley.
 
15B53A77-93BC-4317-9CEE-DD3B600D241F.jpeg5A06535C-B892-4156-92F4-6FAB0C083948.jpeg
Pulled some old concrete curbs that were taken over by cedar roots under a space that I’m repurposing for a carport. Used it as an opportunity to test my welds on the bumper. 4lo and a steady foot, she came clean.

Also walked up the hill after a day of yard cleanup and that evening light was hitting juuust right.
 
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