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Old 02-24-2012, 12:41 PM   #61
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Smart move.

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Old 02-24-2012, 02:17 PM   #62
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Either way was a smart move. He bought a Jeep. Thats all that matters!

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Old 02-24-2012, 02:43 PM   #63
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Old 02-24-2012, 07:16 PM   #64
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Thanks for all the help i bought a 4.0L i dont care about how much gas it takes and stuff the only that matters at the end of the day is its a Jeep
Awesome, welcome to the madness/family
I hope it serves you well.
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Old 02-24-2012, 10:46 PM   #65
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I almost forgot to add......Good decision. Even with all the bickering about 2.5 and 4.0......I have never seen anyone swap a 2.5 to replace a 4.0
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Old 02-25-2012, 03:05 AM   #66
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Haha when other pick up trucks or get stuck while out mudding and i dont ill say "its a jeep thing" love my jeep thanks for all of your guys help
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Old 02-25-2012, 03:06 AM   #67
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Or something*
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Old 02-25-2012, 08:27 AM   #68
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I've never seen anyone swap out a V8 for a 4.0L either.
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Old 02-25-2012, 10:03 PM   #69
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I've never seen anyone swap out a V8 for a 4.0L either.
Yeah.....no v-8's in the Yj's from the factory. Most stock 350's only have a few more HP than a 4.0 believe it or not. The 350's are just so easy to get more HP from bolt on parts.

I was thinking about the topic of this thread today as I drove my very weak 2.5 on the interstate for a 60 mile round trip twice to look at and then purchase a welder and air compressor. I have to call BS on the towing a 29' trailer going 70+ and crap about passing other vehicles like it is no problem. If a 2.5 YJ can do that I would love to see it, and just can't believe that at all.
And a "Marginal" difference between the two? get real 120 hp vs 190hp and 135ft lbs vs 210ft lbs of torque. I own both and both are tuned properly, and I always use 87 octane from the same station.
This mess about not driving it hard by revving the 2.5 to 4,000+ rpm's .....Yes they may make more power at higher rpm's as most motors do, but they are not designed to be driven like that. Look where the shift light comes on. Yeah, I know some say ignore the shift light, but it was put there in the "design" of the vehicle.
One of my best friends is a factory trained Jeep mechanic, and has been working on them for over 15 years. Now he has his own shop specializing in Jeeps. He laughed when I sent him a few of these threads, and pretty much echo'd what have been saying here. He said drive your 4.0's for hauling and highway driving, and keep the Yj for around town and off road and you are fine. Which is what I do most of the time.

The reason I am so into this topic, is I knew better when i was looking for a YJ but was very misled on this issue by people bragging so heavily about the 2.5 engine.
Don't get me wrong, they are fine for most people, but while I was driving down the road today giving my 2.5 as much as it could take to keep it at 65 mph I kept laughing and saying "marginal difference" .
That got me to thinking...............

I then got back to my house and got my 88 XJ with over 250,000 miles on it with 33's which is what I have on my YJ. Put the trailer on it and hit the road to get my stuff I bought. There is nothing "marginal" about the difference. I used more gas on the 2.5 than on my 4.0 and the 4.0 was pulling a trailer empty there and full on the way back. The YJ was with no trailer and with the wind it would barely stay at 65.The other thing i would like to add is that while on the highway I can just mash the gas to the floor and the 4.0 picks up speed quickly and can pass as needed safely. The 2.5 if you mash the gas to the floor even, it slowly increases speed but you have to be patient to notice. There is so much difference it isn't even funny on the highway.

Both were full when I started the trip, and the YJ took 8.25 gallons and the XJ took 7.5 gallons to fill back up.
It was windy today, but I still think it was a fair comparison. I put the same load behind the YJ and it was all I could do to get to 65mph, and it took over a mile to do so (1 6/10 to be exact) shifting at 3,000 rpm's like the 4.0. I then shifted like recommended here by the 2.5 lovers, at 4,500 rpm's and it did much better to 3rd gear, then in 4th it just flattened out and slowly got to 65 about 1/2 mile shorter I also tried a short trip on my other 4.0 with an auto tranny to pull the same load and it was about the same.
This was an experiment I had to try, and I actually thought the 2.5 was better on gas when I got it, but it is only better if I stay under 50 mph and drive it easy.
Still I will say before all the poo gets flying......I am no expert, and I am only trying to keep the next guy/gal from getting misled by false claims. I have had a YJ with a 4.0, and I know this makes me no expert, I know more about the subject than those that have not had both to compare. Maybe the air is different in NC or something like that.
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Old 02-25-2012, 10:57 PM   #70
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If you want gas milage, don't go Jeep. If you want to play do it with the 4.0. I have been both on and off road with both 2.5 and 4.0. If I ever have to buy another Jeep I won't even look at a 2.5.
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Old 02-25-2012, 11:57 PM   #71
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Most stock 350's only have a few more HP than a 4.0 believe it or not. The 350's are just so easy to get more HP from bolt on parts.
I agree with most of your post, but it's not horsepower that makes a v-8 swap so tempting its the torque. Most stock v-8's, while a lot of the only make a few more horsepower than the 4.0L, make about 100 ft. lbs. more torque than the 4.0L. Case in point is the 5.9L Magnum that I'm putting in mine. It's only rated for 35 more horsepower than the 4.0L (245hp), but it makes 330 ft. lbs. of torque. That's almost 2.5 times more torque than the 2.5L and more than 1.5 times more than the 4.0L. As far as fuel mileage concerns. This motor came out of my van which got 13 mpg in town and 18-19 on the highway. My 2.5L only gets 15 mpg anywhere. I've got to believe that being down 2500 lbs. from the van that this motor easily has the potential to at least equal the gas mileage of the four crapper. Even if it doesn't who cares. The power to fry all fours is the only motivation I need.

Wanna take bets as to which axle I can grenade first? No worries as I've got a hp dana 44 front and a dana 60 rear under the bench. Once I've blown the first axle I'll yank em both and s.o.a. the new ones.
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Old 02-26-2012, 12:29 AM   #72
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I agree with most of your post, but it's not horsepower that makes a v-8 swap so tempting its the torque. Most stock v-8's, while a lot of the only make a few more horsepower than the 4.0L, make about 100 ft. lbs. more torque than the 4.0L. Case in point is the 5.9L Magnum that I'm putting in mine. It's only rated for 35 more horsepower than the 4.0L (245hp), but it makes 330 ft. lbs. of torque. That's almost 2.5 times more torque than the 2.5L and more than 1.5 times more than the 4.0L. As far as fuel mileage concerns. This motor came out of my van which got 13 mpg in town and 18-19 on the highway. My 2.5L only gets 15 mpg anywhere. I've got to believe that being down 2500 lbs. from the van that this motor easily has the potential to at least equal the gas mileage of the four crapper. Even if it doesn't who cares. The power to fry all fours is the only motivation I need.

Wanna take bets as to which axle I can grenade first? No worries as I've got a hp dana 44 front and a dana 60 rear under the bench. Once I've blown the first axle I'll yank em both and s.o.a. the new ones.
Sounds like a plan
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Old 02-26-2012, 12:33 AM   #73
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I have to call BS on the towing a 29' trailer going 70+ and crap about passing other vehicles like it is no problem.
A 29' trailer? Never heard of a 2.5L owner towing that, but I have heard of a couple towing boats around town. Geared correctly, and with a driver that actually knows how to drive a 2.5L engine in its powerband, you would be surprised. They can tow modest loads as well, managing the 55mph trailer speed limit here in CA on the highway. Modest, not a big load. I've seen a 2.5L or 2 crusing down the freeways with small trailers (unless the humorous LOW OUTPUT 2.5L decal was just to fool you into thinking otherwise).

I've said it before, and i'll state it again:

The 2.5L, while not being a form of powerhouse like a 4.0 or V8, is sufficient for the Jeep Wrangler. Geared correctly, it will cruise at 65mph on the highway. If you want, push it a bit harder and it'll do 75mph. You are not going to hurt the engine by running it at 3500rpm all day, it was designed to run in that RPM range. I pass people all the time on my way to work if I'm in a rush.

Shift light is a bunch of BS, same thing as the Track Bars. My shift light doesn't even work.

And would I consider another 2.5L Jeep? Absolutely, even as a DD. However I wouldn't mind having a nice 4.0 for a DD, to retire mine from the roads for a while so I can begin the teardown and rebuild. Plus I'd like something that can tow a decent sized trailer with a handful of toys.
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Old 02-26-2012, 08:33 AM   #74
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2.5 towing

You can call BS or crap to the towing, doesn't change history. I towed that 29' self contained trailer for many many years and 1,000s of miles with a pretty wide range of vehicles. The 86 Ford extended cab with 302v8 and automatic was the most anemic one. It handled it from a sway standpoint the best, but was the worst for acceleration.

I towed it quite a bit with my 88 Jeep Grand Wagoneer (that was the small one with dual headlights) with the I6 and automatic. It was about comparable to the Wrangler, but that was due to the automatic. Would have done better with a manual and being able to get into the right rpm range when needed. I remember having trouble maintaining traffic flow going through Kansas City, MO due to having to accelerate and decelerate when going from Mpls, MN to Branson, MO.

The 94 S10 Blazer with the V6 was about the same as the 88 Jeep. Maddening when the computer would de-power the engine every time the temperature got to high operating temp, just when you NEEDED the power.

I never said anything about passing with ease in the sense of acceleration. If I said anything about passing without issue, it was related to passing semi's and not having any side sway issues. Yes, I did pass quite a few semi's on the trip from Sturgis to Minneapolis (acutally Eden Prairie) but that was on the interestate where it wasn't a matter of accelerating to pass but rather one of just maintaining speed and happening to be going faster than the other vehicle. Actually, I don't remember any simi's passing me on that particular trip. Certainly did on many other trips and didn't have any sway issues either.

The entire trip, portal to portal, Stugis, SD to Eden Prairie, MN took just 10.75 hours. Actually the torque:weight ratio of the 2.5cyl to that of a fully loaded semi isn't all that much difference, both about 55:1. And you see semi's running 75 & 80 all the time. You don't see fully loaded semi's pulling out and accelerating rapidly either. And you don't see semi's maintaining cruising speed on significant inclines either.

When I worked for the government we towed the snow cats (12,000 lb each on 5,000 lb trailers) with our 77 Jeep Wagoneers with the 360V8 and T-18 4spd transmissions. That was about a 50:1 torque:weight ratio and it was about comparable to towing the 29' trailer with the Wrangler.

As far as wheel base:tow length, the Wrangler:semi is again about the same. The Reese equalizer hitch with the cam action sway control gives as good, or better sway control than the 5th wheel semi hookup. I can attest to that having driven many many thousands of miles with that hitch setup and have never had any kind of sway issues with any of the rigs. Any lesser hitch set up is a totally different situation.
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Old 02-26-2012, 11:16 AM   #75
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Semi's have 16 or more gears to deal with a load also. You may have pulled a trailer like that with the 2.5, and yours may be some kinda special, but the 90 model I have and the 3 friends I wheel with have 92 94 95 Yj's and they all are weak compared to the 4.0 whether it be auto or manual.
My son goes out into the woods with us on his stock XJ with a 4.0 and wheels, and I pulled him out of a hole he was stuck in, and he put the 4.0 in reverse and I dragged me in that same hole. He has all terrains, and I have Dunlop M/T's of the same size. He was showing off and the next time he got stuck I left him there. My point is the 4.0 is much more powerful than the 2.5 every time.
I guess I need to let it go, but that "marginal" statement is what gets me fired up. There is nothing marginal between the two.
The 2.5 was built off of the 4.2 minus the middle 2 cylinders. They bumped up the stroke and compression to give it more power. The 4.0 has a different head, cams, etc. output-wise it is in a different class all together.
Even still, I wouldn't tow anything like that with any of my vehicles even with a stabilizer. The Jeeps are not set up to stop that kind of weight. I am not an expert by any means, but my father owned his own logistics business for 32 years until retirement. I know a little about trucks
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Old 02-26-2012, 11:51 AM   #76
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definition of marginal

I fully agree that under certain conditions the 4.0 has significantly more power/torque than the 2.5. The torque curves alone point that out. However, my position of being marginally better is that it is only in certain specific instances where that is of significance. Under normal driving conditions the extra power of the 4.0 is not of significance because neither are being pushed to their limits. Yes, it is a little more comfortable to be driving at 1500 rpm and have the torque to accelerate moderately without shifting down, but that again is a moderate advantage.

In most cases, the 2.5 can compensate by being raised to a higher rpm, still within the design parameters.

If I can drive the 2.5 at interstate speeds and maintain those speeds under all but a very few, isolated instances, as compared to the total trip, and the 4.0 overcomes those few, then it is of marginal advantage. If 95+% of the time the 2.5 is adequate, then it is marginally inadequate.

However, it certainly can be shown that the 4.0 is inadequate in just as many instances and a V8 is "marginally" better. Does that mean that the V8 does not have significantly more torque? No, it just means that the difference between what the 4.0 was lacking and what it needed was "marginal" and the application of the V8 would only be marginally better.

Now, if you have an application where 100% of the torque is needed, then you go like a buddy did and put in a 396 Crate racing engine, built T400, locked in transfer case, 5.76 gears with lockers at both ends. Now that would be significantly more powerful and more than marginally inadequate for highway travel.

i believe it comes down to the application of the word marginal and not the actual capability of the engines under specific conditions.
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Old 02-27-2012, 07:53 AM   #77
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Totally agree d5string! Well said and straight to the pointe of the topic. It's not a diesel motor and you can't compare. And alot of people put the 6 and 8 cyl in. That's why you get the deals on the 4 and 6 cyl people are selling on here. Because they are going with the 8. I posted something about 4 to 6 on my wall and a guy explained to me what needed to be done so people do that. There are some really smart ass know it all type people on here that don't know what they are talking about
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Old 02-27-2012, 09:32 AM   #78
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It's seems to me that alot of people get fired up about the 2.5. I dont get it.
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Old 02-27-2012, 09:40 AM   #79
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A 2.5 is marginal at best. Its not even in the same category as a 4.0 except mileage.
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Old 02-27-2012, 09:49 AM   #80
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My 2006 2.4 is a dog. I had a 94 2.5 that wasn't much better. No power. I'll never do that again. They don't even put them in jeeps anymore do they? Cause they are junk
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Old 02-27-2012, 01:23 PM   #81
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They don't put 4.0's in Jeeps anymore either. Guess they are junk too?
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Old 02-27-2012, 01:28 PM   #82
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No, they just didn't break down enough for them to make money on repairs.
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Old 02-27-2012, 05:27 PM   #83
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Gosh is this ever going to die? This is becoming like the honda forum. They all think if you put coffee can on the end of the exhaust it magically becomes the fastest thing in town. if you want to compare you need to be running the same gears and the same tires in both. I'm running 37s with 4.88, any of you 2.5/2.4 guys wanna run them??? Marginal??? Joke! More like exponential! I can speak from experience, I HAD the 2.5.
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Old 02-28-2012, 12:56 AM   #84
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37's on any engine with that gearing is going to be hard on it. At least a gas burner. A diesel that would be ideal

^^2.5L's don't "break down" either. 4.0's are just as reliable as 2.5L's.
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Old 02-28-2012, 11:46 AM   #85
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They do like to blow the rods out of um though
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Old 02-28-2012, 11:49 AM   #86
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^ thats what ive heard
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Old 02-28-2012, 11:59 AM   #87
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I have had 4 in the last 15 months with #2 rod either hanging out of the block, or a hole

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Old 02-29-2012, 09:51 AM   #88
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Gosh is this ever going to die?
Nope. You got a few die hard old men that love to go slow and tell us that the 2.5L is the greatest thing since sliced bread


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Old 02-29-2012, 02:13 PM   #89
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We're tired of 6 cylinder folk telling us that our engines are great boat anchors. We DD our 2.5L's, some more than others, I think we know our engines just a wee bit better

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I have had 4 in the last 15 months with #2 rod either hanging out of the block, or a hole

How were they taken care of? Both by you and the PO? you can't say the 2.5L is junk because it blew a rod out. There's so many variables for why they blew rods that you can't just produce a blanketed statement like that and pass it off as fact. Hell I've seen brand new engines blow up, manufacturer defects DO happen... Especially with all of these "American" cars now becoming Canadian and Mexican cars.
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Old 02-29-2012, 02:53 PM   #90
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All I can tell you is this: I am in the jeep business and out of 52 YJ's now in the last 3 years I have had two with bad 4.0's, one had been run low on oil and was locked up, and the other has a wrist pin rattle. Every single 2.5 I have had that isnt running has a rod out of the side or a hole. I am not making a blanket statement, these are facts because I pulled every one out myself and threw the blocks away.

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