re-gearing advice needed

Jeff B

Jeff B

Thanos was right
Joined
Dec 23, 2006
Location
Lincolnton N.C.
99 wrangler 4cyl 5 speed. currently should have 4:10's and it's on 31" rubber

Thing is a gutless. So I am thinking I should re gear. My thought is 4:56. Primary driving will be round town. maybe a few trips to the beach. This is my daughters jeep, with that said I want to improve the fuel mileage also if possible.

What say the great nc4x4?
 
VW diesel swap? 4.56's are only gonna get you 10% more gearing/power. But if you go any numerically higher, the rpms will kill your fuel mileage. Best bet is smaller tires. Otherwise you will have to compromise efficiency. And honestly, I don't think 4.56's are enough of a change to warrant the cost.
 
jeepinmatt said:
VW diesel swap? 4.56's are only gonna get you 10% more gearing/power. But if you go any numerically higher, the rpms will kill your fuel mileage. Best bet is smaller tires. Otherwise you will have to compromise efficiency. And honestly, I don't think 4.56's are enough of a change to warrant the cost.
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I found a cheap gear set for 300 shipped.

Do see your point
 
What about engine mods? Anything can be done to a 2.5slow?

Edit*

Found this.

Jeep 2.5 AMC 4cyl non adjustable Roller Rockers

so 12hp on the engine and 10% on the gears. the engine is rated at IIRc 125hp at 5200rpm

am I thinking correct that between the gears and the roller rockers I would see about 20% more power for all together 625$ ?
 
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The price of gears isn't the issue, it's usually the cost of install that kills it.
 
I had a 95 Wrangler with the 2.5 stock with 4.10 gears way back in the day. I didn't realize that thing was such a nutless wonder until I put 33s under it, and holy balls....that thing was slow. 5th gear was now useless on the highway. But even with the stock tires I had on it (IIRC some 235/75 R15), a slight grade on the highway had me downshifting to 4th. I ended up fixing my power shortage with a 350 swap.

I know that may not be your aim, but a gear swap will gain you a little power back with the 31s. Beyond that, you can try any of the typical engine mods (exhaust/intake/tune etc.). If you really want to go hog wild, you can start looking at other power adders, but those will add cost quickly.
 
Scooter402 said:
I had a 95 Wrangler with the 2.5 stock with 4.10 gears way back in the day. I didn't realize that thing was such a nutless wonder until I put 33s under it, and holy balls....that thing was slow. 5th gear was now useless on the highway. But even with the stock tires I had on it (IIRC some 235/75 R15), a slight grade on the highway had me downshifting to 4th. I ended up fixing my power shortage with a 350 swap.

I know that may not be your aim, but a gear swap will gain you a little power back with the 31s. Beyond that, you can try any of the typical engine mods (exhaust/intake/tune etc.). If you really want to go hog wild, you can start looking at other power adders, but those will add cost quickly.
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Found this.

Jeep 2.5 AMC 4cyl non adjustable Roller Rockers

so 12hp on the engine and 10% on the gears. the engine is rated at IIRc 125hp at 5200rpm

am I thinking correct that between the gears and the roller rockers I would see about 20% more power for all together 625$ ?
 
Jeff B said:
Found this.

Jeep 2.5 AMC 4cyl non adjustable Roller Rockers

so 12hp on the engine and 10% on the gears. the engine is rated at IIRc 125hp at 5200rpm

am I thinking correct that between the gears and the roller rockers I would see about 20% more power for all together 625$ ?
Click to expand...

That sounds like a reasonable estimate, looks like that to be the case by my calculator as well. Good call, I never thought about adding roller rockers. I did a cam swap on mine for what felt (seat of the pants dyno) only like minimal gains...that was when I decided to do an engine swap.

Stuntman Autoworks said:
Turbo
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Jeff B said:
Would be cool. But I don't think that would be easy bolt on.
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Yep, that would be cool...but not an easy bolt on at all. All new exhaust, re-plumbing the entire intake system, flashing the ECM (if it even allows that...), bigger injectors. It's a snowball effect with that route. But would add to some coolness, if the OP wants to drop some big coin in it. Potentially could cost as much as a 6 or 8 cylinder swap.
 
I'm going 4:88 in mine. I have a friend that has installed a set or 2 so I'm good too!
 
Well hell, if you're installing them then go for it.
 
Jody Treadway said:
I'd 4.88 it.
That way you'll have plenty of gear regardless. Also when you/she finds a deal on 33s, bumpers, winch ,etc, you'll be ready.

Buy once, cry once
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Damn. This was my first thought.

To add, 4.88 will keep her slow too. First jeep and all. Guess I should throw this 8.8 in too. (Thanks @GotWood )Gear cost being the same.
 
Jeff B said:
Damn. This was my first thought.

To add, 4.88 will keep her slow too. First jeep and all. Guess I should throw this 8.8 in too. (Thanks @GotWood )Gear cost being the same.
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Went from cheap regear or lifter swap to gears and whole axle swap setting up for 33s and lockers for the future in 5 hrs lol.
 
Stuntman Autoworks said:
Went from cheap regear or lifter swap to gears and whole axle swap setting up for 33s and lockers for the future in 5 hrs lol.
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The cost of the gears for the 8.8 verses the d35 is little. 8.8 is already in the stand waiting and set up for a TJ. Was gonna swap in into my cherokee. But would be less work to bolt into the wrangler for my kid..
 
I used to have a 2.5l. If you drive it like a 4cyl, it's fine. Just rod the shit out of it. It makes more power than a 258, but it does it all at 5000rpm.

4.88s are probably the right answer, but I wouldn't regear if it were me....
 
I've had two 4 bangers with 4.88 gears. I ran 33 on both. When you do the math it is essentially the same as stock. Can probably keep the same speedo drive.
 
she is going to stay on 31" rubber. if she wants to build it then she needs to fund it. This is more to get her back and forth to school and a job.
 
Jody Treadway said:
Of course you wouldn't. You'd have to reply with some smart @ss remark and then throw in a "straw man" remark at somebody.

:D
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If lazy motherfuckers will lay off with the straw man bullshit, I will stop pointing out their lack of cogency.
 
I am going to start with the roller rockers. See how that feels.

Then the regear. Thanks for all the input guys.

@shawn and @Jody Treadway do your wives know about y'alls affair?:lol:
 
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