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Discussion Starter #1
I'm thinking about buying a yj, I had one years ago with a 4 cyl. 5 speed and had (I think) 32" or 33" tires on it. If I remember right though, I had to constantly downshift into 4th gear on the interstate grades to be able to hold 70 mph.

is this simply a gearing issue, or just an anemic engine issue? I see a lot of 4 cyl for sale that are lifted with over sized tires and I'm wondering if that would be an issue.
 

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It's both an anemic engine and gearing issue. With 32/33" and a 5sp trans I highly recommend a 5.13 gear ratio, this will help the lack of power from the 2.5 but won't cure it.
 

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sell the jeep buy one with a 4.0 and do a gear swap
 

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Discussion Starter #4
sell the jeep buy one with a 4.0 and do a gear swap
I don't currently own one yet, I used to though. I took my wife a ride in my moms old YJ with the top and doors off and my plan worked, she gave me her blessing to get one with this coming tax return. currently I'm just trying to do my research and learn a thing or two about them. both my brothers have CJ7s mom has a yj and an LS1 JK unlimited. I'm the oddball lol
 

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Discussion Starter #5
also. Please excuse my ignorance, but I have these same questions about the YJ that I had for the TJ guys...

Can you have both oversized tires and still get 15+ mpg average from a 6 cyl. YJ? I'm assuming I'd have to do a gear swap to achieve this.
how are the hard tops on these, do they seal up well for winter driving?
if I leave the top off at work and it pours the rain down, (aside from just getting interior wet,) will it hurt it? (dash components, ignition, etc.)

with the 6 cyl, geared correctly for tire size, will it have enough power to get out of its own way on an uphill grade on the interstate? our speed limit here in Ohio's Appalachian foothills is 70 mph on I77, however sometimes you need more than that to merge, avoid other cars, etc. Not looking for a hot rod but not a snail either lol

my old 04 4.0 explorer got 14 average, my newer explorer (2013 3.5 non-turbo) gets 19. so I'm not too spoiled by great mpg lol. I know my wife want's me to get an auto so she can drive it too, but honestly I'm not sure I'd want to teach her to drive a manual in a wrangler. If I recall, aren't the syncros easy to bend and mess up in a manual?
 

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I had a 4.0l with 33's and 4.10/11's and an auto. did highway speeds just fine. Not a rocket but certainly not a turtle. go 4.56 if you want more power but the rpms start to get high as I recall. Hard tops keep the elements out just fine if installed correctly. I would say if you plan to take it off road consider replacing the weak dana 35. If its just going to be for around town or a gravel road, stock rear is fine.
 

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All I can tell you is my Jeep would definitely not be satisfactory on any interstate (see my signature below). However, for just slow rolling around the backroads and mild off roading, it's just fine. And, I would never use it for a daily driver unless I lived 3-5 miles from work.
 

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We have 2 YJs with the 2.5l and stock 4.11 gears, both teenage boy daily drivers.
One has 30s and the other 235s so not oversize by much. Here in CO, they are able to maintain the speed limit most of the time; 75 on the interstates. Of course, everyone else is driving 10+ faster. On long uphill pulls they are about 5mph slower than the speed limit and live in the right lane. All else being equal, the 4.0 gives you more margin but the 2.5 works just fine in my opinion. I have a TJ with a 4.0, 3.73s, and 31s and i easily outperform the boys on the highway hills. In town, we are all equal.
 

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I mean......
 

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We have 2 YJs with the 2.5l and stock 4.11 gears, both teenage boy daily drivers.
One has 30s and the other 235s so not oversize by much. Here in CO, they are able to maintain the speed limit most of the time; 75 on the interstates. Of course, everyone else is driving 10+ faster. On long uphill pulls they are about 5mph slower than the speed limit and live in the right lane. All else being equal, the 4.0 gives you more margin but the 2.5 works just fine in my opinion. I have a TJ with a 4.0, 3.73s, and 31s and i easily outperform the boys on the highway hills. In town, we are all equal.
Owning a 2.5l YJ is a life long-lived in the slow lane lol.
 

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Gottagofast, that is FUNNY. 2.5 is a special kind of patience.
 
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Discussion Starter #13
if I found a 4cyl but was in really good shape, how hard would it be to swap engines down the road, would I need to stick with an older vehicle for a donor, or are there easy wire kits to be able to put an engine from a newer engine/trans?
 

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if I found a 4cyl but was in really good shape, how hard would it be to swap engines down the road, would I need to stick with an older vehicle for a donor, or are there easy wire kits to be able to put an engine from a newer engine/trans?
"How hard" depends on what you consider hard.... it's a huge project that will likely take 6 months for most people but could be done in a week by a pro...

Price would likely be $5000 on average but could range from $1000 for someone really creative and well connected up to $20,000 or so....

If all you want is a 6 cyl jeep then stop looking at 4 cyl jeeps.
 

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If all you want is a 6 cyl jeep then stop looking at 4 cyl jeeps.
X2 cheeper to just get the 6 up front.

Find a 2.5 and a 4.0 locally that haven't been modified too much and drive each over the same roads. Include someplace where you need to accelerate (hwy on ramp) and a longish hills. Now you can compare and make your decision.

2.5 note:
Not sure if it's a common problem in both engines but im batting a 1000 on 2.5s with a broken motor mount. Easy to see, easy to fix, and inexpensive but can lead to a broken manifold bolt/leak. Test drive a 2.5 with a cold engine and you can hear if there is a manifold leak before it warms up. Kind of a popping sound from the driver side of the engine. Flaking frame rust anywhere was an immediate walk away for me.

Guys on this forum are fantastic and full of good information.

Good luck.
 

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if I found a 4cyl but was in really good shape, how hard would it be to swap engines down the road, would I need to stick with an older vehicle for a donor, or are there easy wire kits to be able to put an engine from a newer engine/trans?

It's a stupid waste of time and money to swap a 4.0 into a 2.5 jeep.

My theory is the 2.5 jeeps only existed for people planning a V8 swap. Why else would anybody buy one?
 

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It's a stupid waste of time and money to swap a 4.0 into a 2.5 jeep.

My theory is the 2.5 jeeps only existed for people planning a V8 swap. Why else would anybody buy one?
I don't know, but under your theory there are a lot of un-started projects running around LoL

I own a 2.5 in a '94 YJ it's alright for what I do with it which is trail ride and around town. Do I wish it had more power for on-road, sure. Trail rides, where we do I can go anywhere a 4.0, 3.6, 3.8 will, if you know how to drive it.

Will I dump the money into it to do a V8 swap absolutely not. Too many other things come into play doing that swap, which I won't get into now. That's why I own a TJ with a 4.0 also.
 

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Discussion Starter #18
Sorry I didn't clarify... I meant a v8 instead of a 4 or 6. if a 96 bronco averages 12-14mpg is heavier (4,587 lbs curb weight) but slightly more aerodynamic than a brick of a YJ that is 3,241 lb (according to wiki.) would the swap be worth it?
 

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Low HP and LOTS of gear reduction in Jeeps/Willys has worked for 80yrs.
 

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